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Efficacy of face mask in preventing respiratory virus transmission: A systematic review and meta-analysis
Abstract
Background
Conflicting recommendations exist related to whether masks have a protective effect on the spread of respiratory viruses.
Methods
The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement was consulted to report this systematic review. Relevant articles were retrieved from PubMed, Web of Science, ScienceDirect, Cochrane Library, and Chinese National Knowledge Infrastructure (CNKI), VIP (Chinese) database.
Results
A total of 21 studies met our inclusion criteria. Meta-analyses suggest that mask use provided a significant protective effect (OR = 0.35 and 95% CI = 0.24–0.51). Use of masks by healthcare workers (HCWs) and non-healthcare workers (Non-HCWs) can reduce the risk of respiratory virus infection by 80% (OR = 0.20, 95% CI = 0.11–0.37) and 47% (OR = 0.53, 95% CI = 0.36–0.79). The protective effect of wearing masks in Asia (OR = 0.31) appeared to be higher than that of Western countries (OR = 0.45). Masks had a protective effect against influenza viruses (OR = 0.55), SARS (OR = 0.26), and SARS-CoV-2 (OR = 0.04). In the subgroups based on different study designs, protective effects of wearing mask were significant in cluster randomized trials and observational studies.
Conclusions
This study adds additional evidence of the enhanced protective value of masks, we stress that the use masks serve as an adjunctive method regarding the COVID-19 outbreak.
... Strategies to reduce transmission of SARS-CoV-2 include scrupulous handwashing, appropriate mask wearing, eye protection, physical distancing, and avoidance of crowds. [72][73][74] To prevent the transmission of SARS-CoV-2, as it is predominantly transmitted by respiratory droplets, the CDC recommends community use of masks, specifically non-valve multilayer cloth masks, for everyone who is able. 72,73 Multilayer masks, when appropriately worn covering the nose and mouth, can help reduce the emission of virus-laden droplets ("source control") by up to 80%. ...
... [72][73][74] To prevent the transmission of SARS-CoV-2, as it is predominantly transmitted by respiratory droplets, the CDC recommends community use of masks, specifically non-valve multilayer cloth masks, for everyone who is able. 72,73 Multilayer masks, when appropriately worn covering the nose and mouth, can help reduce the emission of virus-laden droplets ("source control") by up to 80%. [72][73][74][75] A meta-analysis found masks had a protective effect against influenza virus (OR 0.55; 95% CI: 0.39-0.76), ...
... 72,73 Multilayer masks, when appropriately worn covering the nose and mouth, can help reduce the emission of virus-laden droplets ("source control") by up to 80%. [72][73][74][75] A meta-analysis found masks had a protective effect against influenza virus (OR 0.55; 95% CI: 0.39-0.76), SARS-CoV (OR 0.26: 95% CI, 0.18-0.37), ...
With the emergence of the SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) virus, the pandemic has resulted in a severe respiratory disease known as COVID-19. Data and literature are limited in the evaluation, treatment, and considerations for pediatric patients including special populations (e.g., neonates, children, immunocompromised patients, and those with sickle cell disease). There exists a need for a comprehensive review of pediatric proven and disproven treatments as therapies continue to emerge. This article evaluates the pharmacologic treatment and prevention therapies used in pediatric patients to date, including emergency use authorizations, as well as rationales for pharmacotherapies not routinely used to treat acute COVID-19 infection. It is important to note this review article is current as of January 25, 2021, given the rapid evolvement of the pandemic.
... The negative pressure reduce the particles escape from the contaminated area by 58%. Documented evidence that this can contain the spread of infectious diseases such as, measles, chickenpox, anthrax, influenza and SARS [7]. ...
... Personal Protective Equipment (PPE) [7] extracted data from 21 studies that regarded effectiveness of face masks, the evidence shows that there is an effect on minimising the overall rate at which the infection is transmitted. Medical and N95 masks produce a significant reduction to the risk of infection. ...
... [4] Meta-analysis studies showed that use of facemasks among healthcare workers and non-healthcare workers can reduce the transmission of infection by 80% and 47% respectively. [5,6] Thereafter it has been stressed to make effective guidelines [7,8] for the proper selection and use of facemasks. Guidelines regarding reuse and sanitization of facemasks have also been issued by Centre for disease control (CDC). ...
... respectively. [5] WHO also promotes the use of facemasks to prevent the spread of infection till a suitable vaccine or drug comes. [4] Therefore masks can act as a signi cant non-pharmaceutical intervention to prevent infection and break the chain of transmission.Since the menace of the respiratory viral infection was not much due to milder diseases and presence of effective anti-viral drugs and vaccines in pre-COVID times, facemasks and their use was not as popular as during present COVID pandemic due to its deadly nature and lack of anti-viral drugs and vaccines against it, therefore use of facemasks and correct knowledge regarding its use has suddenly became a necessity especially among medical professionals. ...
Background- There is a limited literature especially in India on the awareness regarding facemasks among medical professionals. Therefore the aim of the study is to assess the awareness, practices followed and problems faced in using different types of facemasks among medical professionals in a COVID dedicated hospital.
Methodology- An e-survey via was conducted among medical professionals working in a tertiary care (COVID dedicated) hospital of North-India. The survey asked for the general demographic details, knowledge and awareness on facemask use, quality and various problems faced on regular or prolonged use, sanitization / disposal and recommendations to infected and non- infected people in community.
Results- Survey was sent to around 368 medical professionals out of which a total of 150 participants completed the survey giving an overall response rate of 40.8%. The mean score was 9.8 +/- 2.375 out of 21 giving an overall correct rate of 46.67%. 38% and 31.33% participants knew the correct recommendations of facemasks to infected and non-infected people in the community respectively, Only 4.67% knew the correct sanitization procedures, 84% and 69.33% participants reported problems of discomfort on face and sweat issues respectively while 48.7% of the population felt some amount of breathlessness within 1-3 hours with N-95/FFP2 masks.
Discussion- Awareness in this part of the world was low as compared to the western compared to countries (46.67%) which increases significantly with years of experience(p<0.001), however no such correlation of knowledge score with discipline of medical professionals was found. Since, it is the young medical force which is at the forefront to tackle the menace, therefore, institute should provide regular training and knowledge up gradation about the facemasks and adequate and accurate information needs to be disseminated to younger medical professionals via social media to prevent them from the risk of infection.
... By Spring of 2020, the United States (US) became the largest hotbed for COVID-19 cases and has remained since, with a sizeable plurality of the total worldwide cases and grimly boasting the highest cases of related deaths of any country (Johns Hopkins Coronavirus Resource Center, 2020). In the absence of a viable vaccine, governments have implemented traditional public health interventions, such as using masks (Cheng et al., 2020;Eikenberry et al., 2020;Liang et al., 2020;Liu & Zhang, 2020). Despite evidence of the efficacy of masks in reducing viral spread, however, its use in the US greatly varied from county to county (Katz et al., 2020) potentially jeopardizing its benefits (Eikenberry et al., 2020). ...
... By Spring of 2020, the United States (US) became the largest hotbed for COVID-19 cases and has remained since, with a sizeable plurality of the total worldwide cases and grimly boasting the highest cases of related deaths of any country (Johns Hopkins Coronavirus Resource Center, 2020). In the absence of a viable vaccine, governments have implemented traditional public health interventions, such as using masks (Cheng et al., 2020;Eikenberry et al., 2020;Liang et al., 2020;Liu & Zhang, 2020). Despite evidence of the efficacy of masks in reducing viral spread, however, its use in the US greatly varied from county to county (Katz et al., 2020) potentially jeopardizing its benefits (Eikenberry et al., 2020). ...
In the United States, the COVID-19 pandemic became an unconventional vehicle to advance partisan rhetoric and antagonism. Using data available at the individual- (Study 1; N = 4,220), county- (Study 2; n = 3,046), and state-level (n = 49), we found that partisanship and political orientation was a robust and strong correlate of mask use. Political conservatism and Republican partisanship were related to downplaying the severity of COVID-19 and perceiving masks as being ineffective that, in turn, were related to lower mask use. In contrast, we found that counties with majority Democrat partisanship reported greater mask use, controlling for various socioeconomic and demographic factors. Lastly, states with strong cultural collectivism reported greater mask use while those with strong religiosity reported the opposite. States with greater Democrat partisanship and strong cultural collectivism subsequently reported lower COVID-19 deaths, mediated by greater mask use and lower COVID-19 cases, in the five months following the second wave of COVID-19 in the US during the Summer of 2020. Nonetheless, more than the majority for Democrats (91.58%), Republicans (77.52%), and third-party members (82.48%) reported using masks. Implications for findings are discussed.
... Wide-spread use of face-masks has been brought on by the current COVID-19 pandemic. Public health officials have recommended face-masks since studies demonstrated that they reduce SARS-CoV-2 transmission [1,2]. However, this recommendation became controversial and even politicized in some countries, because of concerns about the safety of masks [3,4]. ...
... Healthcare workers are expected to work with full efficiency and therefore deserve PPE that are comfortable, can be worn for extended periods and do not impair cognitive abilities. Symptoms related to an increase in CO2 concentration are believed to start above the NIOSH 8-h threshold of 5000 ppm [2,17]. Our study showed that during donning JustAir® PAPR, CO2 concentration remained much lower as compared to KN95 respirator and valved-respirators use. ...
Background and purpose:
COVID-19 pandemic led to wide-spread use of face-masks, respirators and other personal protective equipment (PPE) by healthcare workers. Various symptoms attributed to the use of PPE are believed to be, at least in part, due to elevated carbon-dioxide (CO2) levels. We evaluated concentrations of CO2 under various PPE.
Methods:
In a prospective observational study on healthy volunteers, CO2 levels were measured during regular breathing while donning 1) no mask, 2) JustAir® powered air purifying respirator (PAPR), 3) KN95 respirator, and 4) valved-respirator. Serial CO2 measurements were taken with a nasal canula at a frequency of 1-Hz for 15-min for each PPE configuration to evaluate whether National Institute for Occupational Safety and Health (NIOSH) limits were breached.
Results:
The study included 11 healthy volunteers, median age 32 years (range 16-54) and 6 (55%) men. Percent mean (SD) changes in CO2 values for no mask, JustAir® PAPR, KN95 respirator and valve respirator were 0.26 (0.12), 0.59 (0.097), 2.6 (0.14) and 2.4 (0.59), respectively. Use of face masks (KN95 and valved-respirator) resulted in significant increases in CO2 concentrations, which exceeded the 8-h NIOSH exposure threshold limit value-weighted average (TLV-TWA). However, the increases in CO2 concentrations did not breach short-term (15-min) limits. Importantly, these levels were considerably lower than the long-term (8-h) NIOSH limits during donning JustAir® PAPR. There was a statistically significant difference between all pairs (p < 0.0001, except KN95 and valved-respirator (p = 0.25). However, whether increase in CO2 levels are clinically significant remains debatable.
Conclusion:
Although, significant increase in CO2 concentrations are noted with routinely used face-masks, the levels still remain within the NIOSH limits for short-term use. Therefore, there should not be a concern in their regular day-to-day use for healthcare providers. The clinical implications of elevated CO2 levels with long-term use of face masks needs further studies. Use of PAPR prevents relative hypercapnoea. However, whether PAPR should be advocated for healthcare workers requiring PPE for extended hours needs to evaluated in further studies.
... Laboratory experiments have found that almost all types of masks can greatly reduce droplet emission and viral shedding by infectious wearers 8,9 , suggesting their effectiveness for source control. Two observational studies 10,11 and recent systematic reviews focusing on SARS-1, MERS and influenza [12][13][14][15] indicate that masks also substantially reduce infection risk to the non-infected wearer, even when their infectious contact is unmasked. Specifically, Chu et al. 12 suggest that the use of a surgical or cotton mask could result in a reduction in infection risk of around 44% (95% CI 11-60%) in a community setting, with stronger associations in a healthcare setting (70% [59-78%]) and using an N95 respirator (96% [70-99.6%]). ...
... The efficacy of masks was defined as the size of the reduction in transmission probability during a contact between a susceptible and an exposed individual when a mask is worn by one or both parties. For protecting the healthy wearer, systematic reviews and meta-analyses in other viruses have found mean effect sizes of around 45% in community settings 12 with a range of approximately 20-80% [12][13][14] . These should be adjusted downwards to account for different mask types, since cloth masks, the kind most commonly used among the UK public 7 , are less effective than the N95 ventilators used by some study participants 12 . ...
As the UK reopened after the first wave of the COVID-19 epidemic, crucial questions emerged around the role for ongoing interventions, including test-trace-isolate (TTI) strategies and mandatory masks. Here we assess the importance of masks in secondary schools by evaluating their impact over September 1–October 23, 2020. We show that, assuming TTI levels from August 2020 and no fundamental changes in the virus’s transmissibility, adoption of masks in secondary schools would have reduced the predicted size of a second wave, but preventing it would have required 68% or 46% of those with symptoms to seek testing (assuming masks’ effective coverage 15% or 30% respectively). With masks in community settings but not secondary schools, the required testing rates increase to 76% and 57%.
... where R 0 can be obtained from (17). Finally, the basic reproduction number of this system, assumed as the average number of infected cases produced by one infected individual during the infectious period assuming a fully susceptible population (S = N) and q = 0 is then ...
... Upon opening, we assumed a reduction in the schools reflecting the measures implemented, such as, the use of face mask (47% effectiveness), the alternated schools schedules (33% less contacts) and overall compliance to mask usage (90%). The effectiveness of the mask usage was based on a meta analysis study which pooled eight studies that measured the reduction in infection risk associated with mask usage by non-health workers [17]. The model was numerically solved via the lsoda function in the deSolve package in the R language and environment for statistical computing, version 4.0.3 ...
In this paper, we present an age-structured SEIR model that uses contact patterns to reflect the physical distance measures implemented in Portugal to control the COVID-19 pandemic. By using these matrices and proper estimates for the parameters in the model, we were able to ascertain the impact of mitigation strategies employed in the past. Results show that the March 2020 lockdown had an impact on disease transmission, bringing the effective reproduction number (R(t)) below 1. We estimate that there was an increase in the transmission after the initial lift of the measures on 6 May 2020 that resulted in a second wave that was curbed by the October and November measures. December 2020 saw an increase in the transmission reaching an R(t) = 1.45 in early January 2021. Simulations indicate that the lockdown imposed on the 15 January 2021 might reduce the intensive care unit (ICU) demand to below 200 cases in early April if it lasts at least 2 months. As it stands, the model was capable of projecting the number of individuals in each infection phase for each age group and moment in time.
... A mask essentially serves as a filter that prevents passage of some portion of viruses from the airway of the transmitter to the airway of exposed contacts. Mask efficacy is therefore mediated by a reduction in exposure viral load which we define as the virus that reaches the airway of the exposed contact after the filtration from masks used by transmitter and/or exposed contact 1,2 . If a potential transmitter as well as an exposed contact are masked, then this filtering process occurs twice potentially amplifying protection. ...
... Mask efficacy is inferior to that of other, less permeable barrier methods to prevent infections such as condoms 1,3,4 . The most commonly used cloth and hospital masks do not provide a perfect facial seal and mask fabric does not block emission or inhalation of all aerosolized viral particles 5,6 . ...
Masks are a vital tool for limiting SARS-CoV-2 spread in the population. Here we utilize a mathematical model to assess the impact of masking on transmission within individual transmission pairs and at the population level. Our model quantitatively links mask efficacy to reductions in viral load and subsequent transmission risk. Our results reinforce that the use of masks by both a potential transmitter and exposed person substantially reduces the probability of successful transmission, even if masks only lower exposure viral load by ~ 50%. Slight increases in mask adherence and/or efficacy above current levels would reduce the effective reproductive number (R e ) substantially below 1, particularly if implemented comprehensively in potential super-spreader environments. Our model predicts that moderately efficacious masks will also lower exposure viral load tenfold among people who get infected despite masking, potentially limiting infection severity. Because peak viral load tends to occur pre-symptomatically, we also identify that antiviral therapy targeting symptomatic individuals is unlikely to impact transmission risk. Instead, antiviral therapy would only lower R e if dosed as post-exposure prophylaxis and if given to ~ 50% of newly infected people within 3 days of an exposure. These results highlight the primacy of masking relative to other biomedical interventions under consideration for limiting the extent of the COVID-19 pandemic prior to widespread implementation of a vaccine. To confirm this prediction, we used a regression model of King County, Washington data and simulated the counterfactual scenario without mask wearing to estimate that in the absence of additional interventions, mask wearing decreased R e from 1.3–1.5 to ~ 1.0 between June and September 2020.
... The protective effect of facemask use against respiratory virus infection was 64% and a 47% risk reduction was observed among non-healthcare workers. Among the studies included, one study observed a 96% reduction of COVID-19 risk among Chinese healthcare workers using facemasks [6]. A recent study also demonstrated face coverings as effective preventive measures in slowing down the viral transmission via droplets by mimicking cough-generated airborne particles in an indoor environment. ...
... This might be because the consciousness of wearing face coverings in public and the supply of face coverings increased as the pandemic progressed. Wearing facemasks is an effective way of preventing viral transmission via coughing droplets [7] and reduces infection of COVID-19 among health care workers [6]. Moreover, stay home order seemed to be more effective at the beginning of the pandemic (Table 4) and, as the virus spread slowed down, states tended to terminate such orders. ...
Long-term PM2.5 exposure might predispose populations to SARS-CoV-2 infection and intervention policies might interrupt SARS-CoV-2 transmission and reduce the risk of COVID-19. We conducted an ecologic study across the United States, using county-level COVID-19 incidence up to 12 September 2020, to represent the first two surges in the U.S., annual average of PM2.5 between 2000 and 2016 and state-level facemask mandates and stay home orders. We fit negative binomial models to assess COVID-19 incidence in association with PM2.5 and policies. Stratified analyses by facemask policy and stay home policy were also performed. Each 1-µg/m3 increase in annual average concentration of PM2.5 exposure was associated with 7.56% (95% CI: 3.76%, 11.49%) increase in COVID-19 risk. Facemask mandates and stay home policies were inversely associated with COVID-19 with adjusted RRs of 0.8466 (95% CI: 0.7598, 0.9432) and 0.9193 (95% CI: 0.8021, 1.0537), respectively. The associations between PM2.5 and COVID-19 were consistent among counties with or without preventive policies. Our study added evidence that long-term PM2.5 exposure increased the risk of COVID-19 during each surge and cumulatively as of 12 September 2020, in the United States. Although both state-level implementation of facemask mandates and stay home orders were effective in preventing the spread of COVID-19, no clear effect modification was observed regarding long-term exposure to PM2.5 on the risk of COVID-19.
... If a susceptible individual wears a mask, α is reduced by 85% (Fig. 1A). Our assumption that wearing masks is more effective to reduce transmission than to prevent getting infected is supported by experimental data 25 . However, if both infectious and susceptible individuals wear masks the probability of transmission is the product of these probabilities (0.0075) and, thus, sufficiently low such that transmission is effectively null. ...
... relation between the percentage of the population wearing masks and the overall number of cases (Fig. 1B). The description of the dynamics of infection generated by this model is consistent with previous clinical studies 9,25 and highlights the benefit of wearing masks (Fig. 1C, Movie 1). If the daily incidence surpasses the treatment capacity, it will overwhelm the healthcare system with detrimental consequences for medical care of infected individuals and increased mortality and morbidity. ...
COVID-19’s high virus transmission rates have caused a pandemic that is exacerbated by the high rates of asymptomatic and presymptomatic infections. These factors suggest that face masks and social distance could be paramount in containing the pandemic. We examined the efficacy of each measure and the combination of both measures using an agent-based model within a closed space that approximated real-life interactions. By explicitly considering different fractions of asymptomatic individuals, as well as a realistic hypothesis of face masks protection during inhaling and exhaling, our simulations demonstrate that a synergistic use of face masks and social distancing is the most effective intervention to curb the infection spread. To control the pandemic, our models suggest that high adherence to social distance is necessary to curb the spread of the disease, and that wearing face masks provides optimal protection even if only a small portion of the population comply with social distance. Finally, the face mask effectiveness in curbing the viral spread is not reduced if a large fraction of population is asymptomatic. Our findings have important implications for policies that dictate the reopening of social gatherings.
... In many studies such as [38,69], face coverings and ejected air flows while breathing, speaking, or coughing are studied. The meta analyses in [70] and [71] find (large) protective effects of face masks for SARS-CoV-2 transmission such as 40% or even a pooled odds ratio of 0.35. In particular, the protective effect of communitywide masks is shown in [72]. ...
Non-pharmaceutical interventions (NPIs) are important to mitigate the spread of infectious diseases as long as no vaccination or outstanding medical treatments are available. We assess the effectiveness of the sets of non-pharmaceutical interventions that were in place during the course of the Coronavirus disease 2019 (Covid-19) pandemic in Germany. Our results are based on hybrid models, combining SIR-type models on local scales with spatial resolution. In order to account for the age-dependence of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), we include realistic prepandemic and recently recorded contact patterns between age groups. The implementation of non-pharmaceutical interventions will occur on changed contact patterns, improved isolation, or reduced infectiousness when, e.g., wearing masks. In order to account for spatial heterogeneity, we use a graph approach and we include high-quality information on commuting activities combined with traveling information from social networks. The remaining uncertainty will be accounted for by a large number of randomized simulation runs. Based on the derived factors for the effectiveness of different non-pharmaceutical interventions over the past months, we provide different forecast scenarios for the upcoming time.
... Several studies support the use of facemasks to provide source control and reduce transmission in the community. [45][46][47][48][49] The risk of transmission after contact with an individual with COVID-19 increases with the closeness and duration of contact and appears highest with prolonged contact in indoor settings. 50 It is possible that many of the FCSW were still hesitant to act on their risk perceptions and preferred taking "a wait and see approach"-perhaps because social distancing can be perceived as difficult and costly. ...
Background:
Sex workers, like others, are facing economic hardships and anxiety about their health and safety due to coronavirus disease-2019 (COVID-19), an infectious disease caused by a novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Universally, most sex work has largely reduced, moved online, or undertaken covertly because of lockdown measures and need for social distancing to break the transmission of SARS-CoV-2. However, the ability of sex workers to protect themselves against COVID-19 depends on their individual and interpersonal behaviors and work environment. In this study, we sought to determine the relationships between COVID-19 knowledge, awareness and prevention practice (KAP) among female commercial sex workers (FCSW) in the Niger Delta region of Nigeria to inform the development of prevention interventions for this vulnerable population.
Methods:
Data used in this study were obtained from a cross-sectional survey of 604 FCSW operating in the Niger Delta region of Nigeria. We used descriptive and inferential statistics to assess their socio-demographic characteristics and COVID-19 KAP adopted against the novel coronavirus. Latent class analysis was used to systematically classify participants' attributes and behaviors into the most likely distinct clusters or risk groups.
Results:
The majority of the FCSW were singles (86.8%) of childbearing ages, 21-35 years (86.2%), with almost three quarters (73.2%) of them having sex with 3-4 clients per day during the COVID-19 pandemic. Overall, almost three quarters of the participants had both good knowledge and awareness about COVID-19 but less than half of them (41.1%) implemented good practice to prevent the spread of the disease. However, a highly significant and positive relationship was recorded between COVID-19 knowledge (r=0.90, p<0.0001) and awareness (r=0.65, p<0.0001), and preventive practice of FCSW, respectively. About 89.1% of the participants were not very familiar with the symptoms of COVID-19 (p<0.0001). Only 10.9% of the FCSW indicated that they wear facemask at all times, while 45.2% of them do not wear facemask during sexual intercourse with their clients (p<0.0001). Based on the FCSW attributes and behaviors, we identified three distinct clusters or risk groups (p<0.0001), namely, low-risk takers (Cluster 1), high-risk takers (Cluster 2) and very high-risk takers (Cluster 3) with latent class prevalence rates (γc) of 41.13% (95% CI: 37.26-45.10), 33.17% (95% CI: 29.53-37.02) and 25.71% (95% CI: 22.38-29.34), respectively.
Conclusion:
Sex work has high transmission potentials for SARS-CoV-2 because of its operational nature, which does not permit social distancing, and thus, renders certain preventive measures practically ineffective. This is a major challenge in the fight against COVID-19 in this high-risk group and calls for the development of operational guidelines and targeted intervention strategies to help reduce the spread of COVID-19 in the Niger Delta region.
... Comparison with the existing literature The results of our review are consistent with several guidelines suggesting that close contact with index cases can result in transmission of SARS-CoV-2 8-10 . Our findings are also consistent with those of a systematic review which concluded that face masks are effective for preventing transmission of respiratory viruses 11 . The results of our review also support those of a previous review which showed that the elderly are at increased risk of infection and mortality with coronavirus 12 . ...
Background: SARS-CoV-2 transmission has been reported to be associated with close contact with infected individuals. However, the mechanistic pathway for transmission in close contact settings is unclear. Our objective was to identify, appraise and summarise the evidence from studies assessing the role of close contact in SARS-CoV-2 transmission.
Methods: This review is part of an Open Evidence Review on Transmission Dynamics of SARS-CoV-2. We conduct ongoing searches using WHO Covid-19 Database, LitCovid, medRxiv, PubMed and Google Scholar; assess study quality based on the QUADAS-2 criteria and report important findings on an ongoing basis.
Results: We included 181 studies: 171 primary studies and 10 systematic reviews. The settings for primary studies were predominantly in home/quarantine facilities (31.6%) and acute care hospitals (15.2%). The overall reporting quality of the studies was low to moderate. There was significant heterogeneity in design and methodology. The frequency of attack rates (PCR testing) was 3.5-75%; attack rates were highest in prison and wedding venues, and in households. The frequency of secondary attack rates was 0.3-100% with rates highest in home/quarantine settings. Three studies showed no transmission if index cases had recurrent infection. Viral culture was performed in three studies of which two found viable virus; culture results were negative where index cases had recurrent infections. Ten studies performed genomic sequencing with phylogenetic analysis – the completeness of genomic similarity ranged from 81-100%. Findings from systematic reviews showed that children were significantly less likely to transmit SARS-CoV-2 and household contact was associated with a significantly increased risk of infection.
Conclusions: The evidence from published studies demonstrates that SARS-CoV-2 can be transmitted via close contact settings. The risk of transmission is greater in household contacts. There was wide variation in methodology. Standardized guidelines for reporting transmission in close contact settings should be developed to improve the quality reporting.
... While efficacy (performance in controlled or ideal conditions) and effectiveness (performance in usual or realworld conditions) are not synonymous [450,509], a large consensus and a growing body of literature have moved forward the uptake of community masking as part of comprehensive NPI bundles or "policy packages" aimed at preventing infections caused by respiratory viruses including SARS-CoV-2 [55,58,261,262,295,464,508,[510][511][512][513][514][515][516]. Importantly, a fact undergirding community mask wearing during the pandemic is the risk of transmission, not only from symptomatic individuals, but also from presymptomatic and asymptomatic individuals (discussed in section 3). ...
Scientists across disciplines, policymakers, and journalists have voiced frustration at the unprecedented polarization and misinformation around coronavirus disease 2019 (COVID-19) pandemic. Several false dichotomies have been used to polarize debates while oversimplifying complex issues. In this comprehensive narrative review, we deconstruct six common COVID-19 false dichotomies, address the evidence on these topics, identify insights relevant to effective pandemic responses, and highlight knowledge gaps and uncertainties. The topics of this review are: 1) Health and lives vs. economy and livelihoods, 2) Indefinite lockdown vs. unlimited reopening, 3) Symptomatic vs. asymptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, 4) Droplet vs. aerosol transmission of SARS-CoV-2, 5) Masks for all vs. no masking, and 6) SARS-CoV-2 reinfection vs. no reinfection. We discuss the importance of multidisciplinary integration (health, social, and physical sciences), multilayered approaches to reducing risk (“Emmentaler cheese model”), harm reduction, smart masking, relaxation of interventions, and context-sensitive policymaking for COVID-19 response plans. We also address the challenges in understanding the broad clinical presentation of COVID-19, SARS-CoV-2 transmission, and SARS-CoV-2 reinfection. These key issues of science and public health policy have been presented as false dichotomies during the pandemic. However, they are hardly binary, simple, or uniform, and therefore should not be framed as polar extremes. We urge a nuanced understanding of the science and caution against black-or-white messaging, all-or-nothing guidance, and one-size-fits-all approaches. There is a need for meaningful public health communication and science-informed policies that recognize shades of gray, uncertainties, local context, and social determinants of health.
... Despite the growing body of scientific evidence of facemasks' efficacy, individuals may not comply or be willing, consciously or subconsciously, to change behaviors and habits of dress (Asadi et al., 2020;Liang et al., 2020;Scheid et al., 2020). To understand facemasking behaviors, preferences, and motivations of emerging adults in the United States, we coordinated with the Survey Research Institute (SRI) at Cornell University to develop a web-based survey. ...
Facemasks have become requisite amid the COVID-19 pandemic. We explore facemasking behaviors, preferences, and attitudes among emerging adults, a “distinct period demographically” within the lifespan. Public opinion polls conducted in May 2020 found that emerging adults were the least compliant when compared to other demographic groups. To understand why, we developed a survey instrument that was administered to a demographically representative quota sample of 1,005 participants. Demographic comparisons revealed that behaviors and attitudes differed significantly by political beliefs, gender, living situation, and race. An exploratory factor analysis revealed six underlying variables: (a) facemask avoidance; (b) concerned adherence (c) vexed faultfinding; (d) statement making; (e) fashion enthusiasm; and (f) hygiene adherence. All factors varied significantly by political affiliation, and in some cases by gender, race, living situation, location, and work/education status. Significant correlations were present between all factors except fashion enthusiasm and vexed faultfinding.
... Masks were assumed to reduce both outward and inward transmission by η i [48], where η i represents the efficacy of the mask for individual i. Meta-analyses that included cotton masks worn by the general population found a reduction in infection risk of about 50% to the adult wearer [49]. Mask efficacy is lower among children than among adults, and lower in younger children (about 15%) than in older children, possibly related to inferior fit or compliance with continuous use [50,51]. ...
School closures may reduce the size of social networks among children, potentially limiting infectious disease transmission. To estimate the impact of K–12 closures and reopening policies on children's social interactions and COVID-19 incidence in California's Bay Area, we collected data on children's social contacts and assessed implications for transmission using an individual-based model. Elementary and Hispanic children had more contacts during closures than high school and non-Hispanic children, respectively. We estimated that spring 2020 closures of elementary schools averted 2167 cases in the Bay Area (95% CI: −985, 5572), fewer than middle (5884; 95% CI: 1478, 11.550), high school (8650; 95% CI: 3054, 15 940) and workplace (15 813; 95% CI: 9963, 22 617) closures. Under assumptions of moderate community transmission, we estimated that reopening for a four-month semester without any precautions will increase symptomatic illness among high school teachers (an additional 40.7% expected to experience symptomatic infection, 95% CI: 1.9, 61.1), middle school teachers (37.2%, 95% CI: 4.6, 58.1) and elementary school teachers (4.1%, 95% CI: −1.7, 12.0). However, we found that reopening policies for elementary schools that combine universal masking with classroom cohorts could result in few within-school transmissions, while high schools may require masking plus a staggered hybrid schedule. Stronger community interventions (e.g. remote work, social distancing) decreased the risk of within-school transmission across all measures studied, with the influence of community transmission minimized as the effectiveness of the within-school measures increased.
... The findings of this study are relevant to the science underlying the use of respiratory mask in preventing transmission of viral particles [88]. The data summarised here and in Table 2 shows that the true measurement of infectious dose in animals and extrapolation to human is not possible. ...
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is pandemic. Prevention and control strategies require an improved understanding of SARS-CoV-2 dynamics. We did a rapid review of the literature on SARS-CoV-2 viral dynamics with a focus on infective dose. We sought comparisons of SARS-CoV-2 with other respiratory viruses including SARS-CoV-1 and Middle East respiratory syndrome coronavirus. We examined laboratory animal and human studies. The literature on infective dose, transmission and routes of exposure was limited specially in humans, and varying endpoints were used for measurement of infection. Despite variability in animal studies, there was some evidence that increased dose at exposure correlated with higher viral load clinically, and severe symptoms. Higher viral load measures did not reflect coronavirus disease 2019 severity. Aerosol transmission seemed to raise the risk of more severe respiratory complications in animals. An accurate quantitative estimate of the infective dose of SARS-CoV-2 in humans is not currently feasible and needs further research. Our review suggests that it is small, perhaps about 100 particles. Further work is also required on the relationship between routes of transmission, infective dose, co-infection and outcomes.
... Recent observational studies and meta-analyses of mask effectiveness have estimated that mask usage reduces the risk of respiratory virus spread by 70% to 80%. 22 Efficacy of home-made masks at preventing spread of influenza showed that surgical masks are three times more effective at blocking micro-organism transmission than homemade masks [23][24][25] although none of these studies include randomized control trials. 26 There is, however, evidence that communities in which masks were in widespread use exhibited significantly reduced community spread. ...
The ongoing COVID-19 pandemic has highlighted the importance of aerosol dispersion in disease transmission in indoor environments. The present study experimentally investigates the dispersion and build-up of an exhaled aerosol modeled with polydisperse microscopic particles (approximately 1 lm mean diameter) by a seated manikin in a relatively large indoor environment. The aims are to offer quantitative insight into the effect of common face masks and ventilation/air purification, and to provide relevant experimental metrics for modeling and risk assessment. Measurements demonstrate that all tested masks provide protection in the immediate vicinity of the host primarily through the redirection and reduction of expiratory momentum. However, leakages are observed to result in notable decreases in mask efficiency relative to the ideal filtration efficiency of the mask material, even in the case of high-efficiency masks, such as the R95 or KN95. Tests conducted in the far field (2 m distance from the subject) capture significant aerosol build-up in the indoor space over a long duration (10 h). A quantitative measure of apparent exhalation filtration efficiency is provided based on experimental data assimilation to a simplified model. The results demonstrate that the apparent exhalation filtration efficiency is significantly lower than the ideal filtration efficiency of the mask material. Nevertheless, high-efficiency masks, such as the KN95, still offer substantially higher apparent filtration efficiencies (60% and 46% for R95 and KN95 masks, respectively) than the more commonly used cloth (10%) and surgical masks (12%), and therefore are still the recommended choice in mitigating airborne disease transmission indoors. The results also suggest that, while higher ventilation capacities are required to fully mitigate aerosol build-up, even relatively low air-change rates (2 h À1) lead to lower aerosol build-up compared to the best performing mask in an unventilated space.
... While this assumption may be optimistic in other global contexts, the lower case counts in NSW mean that contact tracers have far greater capacity for rigorous ongoing follow-up of contacts, and breaches of isolation are escalated with local authorities, as stipulated in national guideline documents. 50 Role of the funding source The funders had no role in the design or execution of this study. ...
Objectives
The early stages of the COVID-19 pandemic illustrated that SARS-CoV-2, the virus that causes the disease, has the potential to spread exponentially. Therefore, as long as a substantial proportion of the population remains susceptible to infection, the potential for new epidemic waves persists even in settings with low numbers of active COVID-19 infections, unless sufficient countermeasures are in place. We aim to quantify vulnerability to resurgences in COVID-19 transmission under variations in the levels of testing, tracing and mask usage.
Setting
The Australian state of New South Wales (NSW), a setting with prolonged low transmission, high mobility, non-universal mask usage and a well-functioning test-and-trace system.
Participants
None (simulation study).
Results
We find that the relative impact of masks is greatest when testing and tracing rates are lower and vice versa. Scenarios with very high testing rates (90% of people with symptoms, plus 90% of people with a known history of contact with a confirmed case) were estimated to lead to a robustly controlled epidemic. However, across comparable levels of mask uptake and contact tracing, the number of infections over this period was projected to be 2–3 times higher if the testing rate was 80% instead of 90%, 8–12 times higher if the testing rate was 65% or 30–50 times higher with a 50% testing rate. In reality, NSW diagnosed 254 locally acquired cases over this period, an outcome that had a moderate probability in the model (10%–18%) assuming low mask uptake (0%–25%), even in the presence of extremely high testing (90%) and near-perfect community contact tracing (75%–100%), and a considerably higher probability if testing or tracing were at lower levels.
Conclusions
Our work suggests that testing, tracing and masks can all be effective means of controlling transmission. A multifaceted strategy that combines all three, alongside continued hygiene and distancing protocols, is likely to be the most robust means of controlling transmission of SARS-CoV-2.
... A recent report suggested that wearing masks reduces the emission of virus-laden aerosols and droplets, 18 and a meta-analysis indicated that the use of masks provides a significant protective effect (odds ratio = 0.35; 95% confidence interval, 0.24-0.51) in preventing respiratory virus transmission. 19 This evidence suggests that the transmission of respiratory viruses in general, not only adenovirus but also others including influenza virus, can all have been affected. As a result, there were astonishingly few cases of seasonal influenza in Australia, Chile, and South Africa between April and July 2020, and this has been attributed to these changed personal hygiene practices. ...
Background:
The coronavirus disease 2019 (COVID-19) pandemic began in December 2019. While it has not yet ended, COVID-19 has already created transitions in health care, one of which is a decrease in medical use for health-related issues other than COVID-19 infection. Korean soldiers are relatively homogeneous in terms of age and physical condition. They show a similar disease distribution pattern every year and are directly affected by changes in government attempts to control COVID-19 with nonpharmaceutical interventions. This study aimed to identify the changes in patterns of outpatient visits and admissions to military hospitals for a range of disease types during a pandemic.
Methods:
Outpatient attendance and admission data from all military hospitals in South Korea from January 2016 to December 2020 were analyzed. Only active enlisted soldiers aged 18-32 years were included. Outpatient visits where there was a diagnosis of pneumonia, acute upper respiratory tract infection, infectious conjunctivitis, infectious enteritis, asthma, allergic rhinitis, allergic conjunctivitis, atopic dermatitis, urticaria, and fractures were analyzed. Admissions for pneumonia, acute enteritis, and fractures were also analyzed. All outpatient visits and admissions in 2020 for each disease were counted on a weekly basis and compared with the average number of visits over the same period of each year from 2016 to 2019. The corrected value was calculated by dividing the ratio of total weekly number of outpatient visits or admissions to the corresponding medical department in 2020 to the average in 2016-2019.
Results:
A total of 5,813,304 cases of outpatient care and 143,022 cases of admission were analyzed. For pneumonia, the observed and corrected numbers of outpatient visits and admissions in 2020 decreased significantly compared with the average of other years (P < 0.001). The results were similar for outpatient visits for acute upper respiratory tract infection and infectious conjunctivitis (P < 0.001), while the corrected number of outpatient visits for infectious enteritis showed a significant increase in 2020 (P = 0.005). The corrected number of outpatient visits for asthma in 2020 did not differ from the average of the previous 4 years but the number of visits for the other allergic diseases increased significantly (P < 0.001). For fractures, the observed and corrected numbers of outpatient visits and admissions in 2020 decreased significantly compared with the average of other years (P < 0.001).
Conclusion:
During the COVID-19 pandemic, outpatient visits to military hospitals for respiratory and conjunctival infections and fractures decreased, whereas visits for allergic diseases did not change or increased only slightly. Admissions for pneumonia decreased significantly in 2020, while those for acute enteritis and fractures also decreased, but showed an increased proportion compared with previous years. These results are important because they illustrate the changing patterns in lifestyle as a result of public encouragement to adopt nonpharmaceutical interventions during the pandemic and their effect on medical needs for both infectious and noninfectious diseases in a select group.
... The National Institute for Occupational Safety and Health defined N95 and N99 standards in the United States and the European Committee for Standardization specified with the EN 143 regulation standards for type 1, 2 and 3 filtering face pieces (FFP1, FFP2 and FFP3). While there is an undoubted role of facial masks as mean to reduce the spread of aerosols and droplets from unaware infected patients, it is unclear whether non-PPE devices can offer some degree of protection to healthy individuals [10,11]. ...
Background:
Since the beginning of the COVID-19 pandemics, masking policies have been advocated. While masks are known to prevent transmission towards other individuals, it is unclear if different types of facial masks can protect the user from inhalation. The present study compares in-vitro different commercial and custom-made facial masks at different distances and breathing patterns.
Methods:
Masks were placed on a head mannequin connected to a lung simulator, using a collecting filter placed after the mannequin airway. Certified, commercial and custom-made masks were tested at three different distances between the emitter and the mannequin: 40 cm, 80 cm and 120 cm. Two patterns of breathing were used, simulating normal and polypneic respiration. A solution of methylene blue was nebulized with a jet nebulizer and different mask-distance-breathing pattern combinations were tested. The primary endpoint was the inhaled fraction, defined as the amount of methylene blue detected with spectrophotometry expressed as percent of the amount detected in a reference condition of zero distance and no mask.
Findings:
We observed a significant effect of distance (p < 0.001), pattern of breathing (p = 0.040) and type of mask (p < 0.001) on inhaled fraction. All masks resulted in lower inhaled fraction compared to breathing without mask (p < 0.001 in all comparisons), ranging from 41.1% ± 0.3% obtained with a cotton mask at 40 cm distance with polypneic pattern to <1% for certified FFP3 and the combination of FFP2 + surgical mask at all distances and both breathing pattern conditions.
Discussion:
Distance, type of device and breathing pattern resulted in highly variable inhaled fraction. While the use of all types of masks resulted relevantly less inhalation compared to distancing alone, only high-grade certified devices (FFP3 and the combination of FFP2 + surgical mask) ensured negligible inhaled fraction in all conditions.
... Then, respondents were asked to consider a hypothetical situation in which, at the entrance of the grocery store, signage states, "To assure your safety and minimize direct contact, starting today, in addition to our routine sanitation, employees will wear facemasks and gloves." The rationale for employing this preventive action is that the use of facemasks has been controversial since the pandemic began [18,19] with recent evidence suggesting that wearing facemasks is effective in reducing the risk of respiratory virus infection [20]. A few days after the survey was distributed, the CDC reversed its guidance on facemasks from not recommending their use for people who were not sick to urging all people to wear any type of facemask, even a makeshift. ...
During the COVID-19 lockdown in the US, many businesses were shut down temporarily. Essential businesses, most prominently grocery stores, remained open to ensure access to food and household essentials. Grocery shopping presents increased potential for COVID-19 infection because customers and store employees are in proximity to each other. This study investigated shoppers' perceptions of COVID-19 infection risks and put them in context by comparing grocery shopping to other activities outside home, and examined whether a proactive preventive action by grocery stores influence shoppers' perceived risk of COVID-19 infection. Our data were obtained via an anonymous online survey distributed between April 2 and 10, 2020 to grocery shoppers in New York State (the most affected by the pandemic at the time of the study) and Washington State (the first affected by the pandemic). We found significant factors associated with high levels of risk perception on grocery shoppers. We identified some effective preventive actions that grocery stores implement to alleviate anxiety and risk perception. We found that people are generally more concerned about in-store grocery shopping relative to other out-of-home activities. Findings suggest that a strict policy requiring grocery store employees to use facemasks and gloves greatly reduced shoppers' perceived risk rating of infection of themselves by 37.5% and store employees by 51.2%. Preventive actions by customers and businesses are critical to reducing the unwitting transmission of COVID-19 as state governments prepare to reopen the economy and relax restrictions on activities outside home.
... as a means of preventing transmission (Chu et al., 2020;Chughtai et al., 2016;Eikenberry et al., 2020;Li et al., 2020;Liang et al., 2020;Macintyre & Chughtai, 2020). However, the effectiveness of the use of masks depends on the general public's behavior in handling face masks. ...
Objectives
Investigation of potential erroneous behavior in the general public's use of face masks during the COVID‐19 pandemic.
Design
We conducted a naturalistic observational study in the period from April to June 2020.
Sample
In two western Austrian provinces, a total of 2080 persons were observed in front of 24 grocery stores.
Measurement
The frequencies and types of erroneous behavior in the use of face masks were collected using a standardized observation form.
Results
A total of 2080 persons were observed. Almost one‐third of all observations (n = 648; 31.2%) showed erroneous behavior before positioning the face masks. Another 935 (45.0%) persons touched the face mask front during the adjustment via mouth and nose, 501 (24.1%) persons touched the face mask front in the period after the adjustment. A total of 116 (5.6%) persons showed erroneous behavior in each sequence of the observation unit. Overall, almost half of all people observed showed at least one erroneous behavior within the observation period.
Conclusions
The behavior of the general public in handling face masks is highly error‐prone. Decision makers must increasingly provide accompanying information and educational measures in order to encourage the population at risk to use face masks correctly.
... Masking policies are a prime example of this delayed response. Even though we have known since the early days of the pandemic that COVID-19 is most likely readily transmitted through aerosol particles and mask-wearing substantially reduces the risk of transmission [38,39], few correctional systems enforced mandatory mask-wearing among correctional staff. By mid-August, 2020, only 30 states required that state correctional staff wear a mask while working [40]. ...
Background:
Our objective was to examine the temporal relationship between COVID-19 infections among prison staff, incarcerated individuals, and the general population in the county where the prison is located among federal prisons in the United States.
Methods:
We employed population-standardized regressions with fixed effects for prisons to predict the number of active cases of COVID-19 among incarcerated persons using data from the Federal Bureau of Prisons (BOP) for the months of March to December in 2020 for 63 prisons.
Results:
There is a significant relationship between the COVID-19 prevalence among staff, and through them, the larger community, and COVID-19 prevalence among incarcerated persons in the US federal prison system. When staff rates are low or at zero, COVID-19 incidence in the larger community continues to have an association with COVID-19 prevalence among incarcerated persons, suggesting possible pre-symptomatic and asymptomatic transmission by staff. Masking policies slightly reduced COVID-19 prevalence among incarcerated persons, though the association between infections among staff, the community, and incarcerated persons remained significant and strong.
Conclusion:
The relationship between COVID-19 infections among staff and incarcerated persons shows that staff is vital to infection control, and correctional administrators should also focus infection containment efforts on staff, in addition to incarcerated persons.
... In some centers, a mortality rate of 30% was reached in admitted patients, 10 with the emergency services overwhelmed and patients occupying corridors, libraries, gyms and even cafeterias. Due to the lack of initial scientific evidence on the route of transmission, 11,12 and to the global problems in the supply of protective material, 13 masks began to be used on a massive scale within the hospital when the infection had already been established and the virus was transmitted through the closed institutions. As the pandemic accelerated in early March, access to personal protective equipment (PPE) for workers was in short supply, was lacking in many centers, or did not meet minimum requirements to ensure user safety. ...
... Authors of a rapid systematic review [50] on the efficacy of face masks suggest that masking wearing could be beneficial in the context of COVID-19 outbreak especially universal community mask use and in the health care settings as well. Findings from a systematic review and meta-analysis [51] showed that mask wearing by health workers and non-health workers and in the general community is and efficient in preventing the infection by SARS-CoV2. Another study [52] showed that wearing masks in public is crucial as a preventive measure to ensure a significant reduction in the daily infected cases. ...
Background
In December 2019, a novel coronavirus (2019-nCoV) was recognized in Wuhan, China. It was characterised by rapid spread causing a pandemic. Multiple public health interventions have been implemented worldwide to decrease the transmission of the 2019 novel coronavirus disease (COVID-19). The objective of this systematic review is to evaluate the implemented public health interventions to control the spread of the outbreak of COVID-19. Methods: We systematically searched PubMed, Science Direct and MedRxiv for relevant articles published in English up to March 16, 2021. We included quasi experimental studies, clinical trials, cohort studies, longitudinal studies, case-control studies and interrupted time series. We included the studies that investigated the effect of the implemented public health measures to prevent and control the outbreak of 2019 novel coronavirus disease (COVID-19).
Results
The database search using the predefined combinations of Mesh terms found 13,497 studies of which 3595 in PubMed, 7393 in Science Direct 2509 preprints in MedRxiv. After removal of the duplicates and the critical reading only 18 articles were included in this systematic review and processed for data extraction.
Conclusions
Public health interventions and non-pharmaceutical measurements were effective in decreasing the transmission of COVID-19. The included studies showed that travel restrictions, borders measures, quarantine of travellers arriving from affected countries, city lockdown, restrictions of mass gathering, isolation and quarantine of confirmed cases and close contacts, social distancing measures, compulsory mask wearing, contact tracing and testing, school closures and personal protective equipment use among health workers were effective in mitigating the spread of COVID-19.
... The World Health Organization (WHO) declared the novel SARS-CoV-2 coronavirus disease 2019 (COVID-19) outbreak a pandemic on the 11 th of March 2020 [1], and face masks swiftly became one of the most visible symbols of the pandemic [2,3]. The emerging consensus is that mask wearing reduces the chances of both catching and spreading the virus and thus protects both the wearer herself and other people around her [4][5][6][7]. ...
Human behavior can have effects on oneself and externalities on others. Mask wearing is such a behavior in the current pandemic. What motivates people to wear face masks in public when mask wearing is voluntary or not enforced? Which benefits should the policy makers rather emphasize in information campaigns-the reduced chances of getting the SARS-CoV-2 virus (benefits for oneself) or the reduced chances of transmitting the virus (benefits for others in the society)? In this paper, we link measured risk preferences and other-regarding preferences to mask wearing habits among 840 surveyed employees of two large Swiss hospitals. We find that the leading mask-wearing motivations change with age: While for older people, mask wearing habits are best explained by their self-regarding risk preferences, younger people are also motivated by other-regarding concerns. Our results are robust to different specifications including linear probability models, probit models and Lasso covariate selection models. Our findings thus allow drawing policy implications for effectively communicating public-health recommendations to frontline workers during the COVID-19 pandemic.
... Masks were assumed to reduce exposure to infection and infectivity among susceptible agents by 50% each. 31,32 Because schools closed in March and moved to remote instruction, there were no kindergarten through grade 12 school interactions until August 24, when schools were allowed to open under a hybrid policy that limited the total number of students to ensure distancing. After August 24, agents were split into 2 equal groups, with one group attending school on even dates and the other on odd dates. ...
Importance
Vaccination against SARS-CoV-2 has the potential to significantly reduce transmission and COVID-19 morbidity and mortality. The relative importance of vaccination strategies and nonpharmaceutical interventions (NPIs) is not well understood.
Objective
To assess the association of simulated COVID-19 vaccine efficacy and coverage scenarios with and without NPIs with infections, hospitalizations, and deaths.
Design, Setting, and Participants
An established agent-based decision analytical model was used to simulate COVID-19 transmission and progression from March 24, 2020, to September 23, 2021. The model simulated COVID-19 spread in North Carolina, a US state of 10.5 million people. A network of 1 017 720 agents was constructed from US Census data to represent the statewide population.
Exposures
Scenarios of vaccine efficacy (50% and 90%), vaccine coverage (25%, 50%, and 75% at the end of a 6-month distribution period), and NPIs (reduced mobility, school closings, and use of face masks) maintained and removed during vaccine distribution.
Main Outcomes and Measures
Risks of infection from the start of vaccine distribution and risk differences comparing scenarios. Outcome means and SDs were calculated across replications.
Results
In the worst-case vaccination scenario (50% efficacy, 25% coverage), a mean (SD) of 2 231 134 (117 867) new infections occurred after vaccination began with NPIs removed, and a mean (SD) of 799 949 (60 279) new infections occurred with NPIs maintained during 11 months. In contrast, in the best-case scenario (90% efficacy, 75% coverage), a mean (SD) of 527 409 (40 637) new infections occurred with NPIs removed and a mean (SD) of 450 575 (32 716) new infections occurred with NPIs maintained. With NPIs removed, lower efficacy (50%) and higher coverage (75%) reduced infection risk by a greater magnitude than higher efficacy (90%) and lower coverage (25%) compared with the worst-case scenario (mean [SD] absolute risk reduction, 13% [1%] and 8% [1%], respectively).
Conclusions and Relevance
Simulation outcomes suggest that removing NPIs while vaccines are distributed may result in substantial increases in infections, hospitalizations, and deaths. Furthermore, as NPIs are removed, higher vaccination coverage with less efficacious vaccines can contribute to a larger reduction in risk of SARS-CoV-2 infection compared with more efficacious vaccines at lower coverage. These findings highlight the need for well-resourced and coordinated efforts to achieve high vaccine coverage and continued adherence to NPIs before many prepandemic activities can be resumed.
... In fact, even before airlines provided PPE to cabin crew members, they were asked to wear PPE (e.g., goggles, aprons, gloves) during flight duty, due to concerns regarding in-flight infection. A previous study reported that wearing a mask could reduce the risk of respiratory virus transmission by 65% overall, and by 96% specifically for COVID-19 (SARS 74%, influenza 55%) [43]. ...
COVID-19 was declared a worldwide pandemic in 2020; thus, preventing in-flight infection transmission is important for stopping global spread via air travel. Infection prevention (IP) performance among aircraft cabin crew is crucial for preventing in-flight transmission. We aimed to identify the level of IP performance and factors affecting IP performance among aircraft cabin crew during the COVID-19 pandemic in South Korea. An online survey was conducted with 177 cabin crew members between August and September 2020. The survey assessed IP performance, and IP awareness, using a five-point Likert scale, and also evaluated simulation-based personal protective equipment (PPE) training experience, and organizational culture. The average IP performance score was 4.56 ± 0.44. Although the performance level for mask-wearing was high (4.73 ± 0.35), hand hygiene (HH) performance (4.47 ± 0.56) was low. Multivariate analysis showed that IP performance was significantly associated with IP awareness (p < 0.05) and simulation-based PPE training experience (p < 0.05). Since HH performance was relatively low, cabin crew and airlines should make efforts to improve HH performance. Furthermore, a high level of IP awareness and PPE training experience can improve IP performance among cabin crew members. Therefore, simulation-based PPE training and strategies to improve IP awareness are essential for preventing in-flight infection transmission.
... Some research findings also indicate possible transmission through aerosol (<5 µm in diameter) (World Health Organization, 2020, July 9). Experimental and epidemiological data support the use of face masks to reduce the spread of SARS-CoV-2 Liang et al., 2020;Howard et al., 2021;Rader et al., 2021). Wearing face masks also reduces the emission of respiratory droplets containing other respiratory viruses such as seasonal human coronaviruses, influenza viruses, and rhino viruses (Leung et al., 2020). ...
The coronavirus pandemic has resulted in the recommended/required use of face masks in public. The use of a face mask compromises communication, especially in the presence of competing noise. It is crucial to measure the potential effects of wearing face masks on speech intelligibility in noisy environments where excessive background noise can create communication challenges. The effects of wearing transparent face masks and using clear speech to facilitate better verbal communication were evaluated in this study. We evaluated listener word identification scores in the following four conditions: (1) type of mask condition (i.e., no mask, transparent mask, and disposable face mask), (2) presentation mode (i.e., auditory only and audiovisual), (3) speaking style (i.e., conversational speech and clear speech), and (4) with two types of background noise (i.e., speech shaped noise and four-talker babble at −5 signal-to-noise ratio). Results indicate that in the presence of noise, listeners performed less well when the speaker wore a disposable face mask or a transparent mask compared to wearing no mask. Listeners correctly identified more words in the audiovisual presentation when listening to clear speech. Results indicate the combination of face masks and the presence of background noise negatively impact speech intelligibility for listeners. Transparent masks facilitate the ability to understand target sentences by providing visual information. Use of clear speech was shown to alleviate challenging communication situations including compensating for a lack of visual cues and reduced acoustic signals.
... A systematic review and meta-analysis in Chinese show wearing of face mask can prevent from influenza virus and SARS-CoV-2. 14,15 The WHO, CDC, and the Ethiopian Ministry of Health all recommended using face masks to control the pandemic across countries, as standards and utilization of face masks is a current hot topic for the most front-line health care providers working at public health institutions at this time, along with other personal protective equipment. However, proper use of a face mask is critical to preventing the spread. ...
Introduction:
The novel coronavirus disease (COVID-19) pandemic began in early 2020, causing tens of thousands of deaths, over a million cases, and widespread socioeconomic disruption.
Objective:
The aim of the study was to assess health care workers' knowledge and practice of proper face mask utilization to prevent the spread of COVID-19 infection in Amhara region referral hospitals, Ethiopia.
Methods:
A cross-sectional institutional-based quantitative study design was conducted from May 15 to 30/2020 using pre-tested self-administrated questionnaire and analyzed by using SPSS version 20.0. The study included 422 health care providers, and the sample size was determined using a single population proportion formula with the assumption of a p value of 0.05. Data were collected using a consecutive sampling technique from all referral hospitals and were analyzed using descriptive statistics. Finally, the outcome was presented in the form of a text and a table.
Results:
The overall knowledge and practice of health care providers regarding proper face mask utilization were 278 (65.8%) and 252 (59.5%), respectively. Of them, 284 (67.3%) knew that face masks were worn with the white side facing in, 264 (62.6%) knew that face masks had three layers, and 331 (78.4%) knew that surgical face masks were worn for up to 8 hours.
Conclusion and recommendation:
The respondent's knowledge of proper face mask usage was high, in comparison with another studies but the proper utilization of face mask was relatively low. Ethiopian ministry of health in collaboration with Amhara region, zonal and woreda health institution works together to increase utilization of face mask and to alleviate scarcity of resource and provide training to the health care providers about the proper utilization of face mask to tackle COVID-19.
... Moreover, the fact that this norm is not associated with the social isolation index is an interesting result because it highlights the specificity of this index as a mediator of quarantine measures. Face masks protect against infection by several respiratory diseases [19]. Modeling studies with the population of two North American cities showed that the use of masks by 80% of the population could reduce mortality by 24-65% [20]. ...
This study aimed to estimate the effect of restrictive laws on actual social isolation and COVID-19 mortality. Moreover, we evaluated how community adherence, measured with an index of social isolation, would mediate the lockdown effect on COVID-19 mortality.
Methods: This ecological study assessed the legislations published until June 30, 2020, in the Brazilian state of Ceara. We performed a systematic review and classification of restrictive norms and estimated their immediate effect on social isolation, measured by an index based on mobile data, and the subsequent impact on COVID-19 mortality (three weeks later). A mediation analysis was performed to estimate the effect of rigid lockdown on mortality that was explained for effective social isolation.
Results: The social isolation index showed an increase of 11.9% (95% CI: 2.9% - 21%) during the days in which a rigid isolation norm (lockdown) was implemented. Moreover, this rigid lockdown was associated with a reduction of 26% (95% CI: 21% - 31%) in the three-week-delayed mortality. We also calculated that the rigid lockdown had the indirect effect, i.e., mediated by adherence to social isolation, of reducing COVID-19 mortality by 38.24% (95% CI: 21.64% to 56.07%). Therefore, the preventive effect of this norm was fully explained by the actual population adherence, reflected in the social isolation index. On the other hand, mandatory mask use was associated with 11% reduction in COVID-19 mortality (95% CI: 8% - 13%).
Conclusions: We estimated the effect of quarantine regulations on social isolation and evidenced that a rigid lockdown law led to a reduction of COVID-19 mortality in one state of Brazil. In addition, the mandatory masks norm was an additional determinant of the reduction of this outcome.
... As of December 2020, SARS-CoV-2, the virus responsible for COVID-19 has infected at least 66 million people worldwide and caused more than 1.5 million deaths [1]. Numerous studies have analyzed the role played by masks during the COVID-19 pandemic [2][3][4][5][6]: masks have a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 been associated with a reduction in the infection rate among health care workers in a large hospital network [7], mask mandates have helped reduce the number of cases in the United States and in Germany [8][9][10], and simulations have shown that wearing a mask can protect against droplet infection by preventing the spread of viral particles [11][12][13][14][15][16]. Despite this evidence, 6 states recently lifted their mask mandates even though they have some of the lowest vaccination rates in the country. ...
We extend previous studies on the impact of masks on COVID-19 outcomes by investigating an unprecedented breadth and depth of health outcomes, geographical resolutions, types of mask mandates, early versus later waves and controlling for other government interventions, mobility testing rate and weather. We show that mask mandates are associated with a statistically significant decrease in new cases (-3.55 per 100K), deaths (-0.13 per 100K), and the proportion of hospital admissions (-2.38 percentage points) up to 40 days after the introduction of mask mandates both at the state and county level. These effects are large, corresponding to 14% of the highest recorded number of cases, 13% of deaths, and 7% of admission proportion. We also find that mask mandates are linked to a 23.4 percentage point increase in mask adherence in four diverse states. Given the recent lifting of mandates, we estimate that the ending of mask mandates in these states is associated with a decrease of -3.19 percentage points in mask adherence and 12 per 100K (13% of the highest recorded number) of daily new cases with no significant effect on hospitalizations and deaths. Lastly, using a large novel survey dataset of 847 thousand responses in 69 countries, we introduce the novel results that community mask adherence and community attitudes towards masks are associated with a reduction in COVID-19 cases and deaths. Our results have policy implications for reinforcing the need to maintain and encourage mask-wearing by the public, especially in light of some states starting to remove their mask mandates.
... Consistent with our findings, a study in India [28] showed that half of the participants did not have access to masks. Because masks are particularly important in controlling the pandemic [29] , health policymakers may be particularly interested in addressing masks' availability. Only 61% complied with home quarantining, probably because there were few restrictions on leaving home in Iran, and respondents needed to maintain their jobs. ...
... These two control measures were selected as they have been more commonly adopted by countries, with the issuance of mask mandates and testing becoming more available for the general public. Moreover, recent analysis has proven that face masks are effective in curbing the spread of the disease in different settings and populations [30][31][32]. In our analysis, we assumed that all of the agents are wearing face masks and will be stopped at the screening checkpoint before entry into the main ritual area. ...
Abstract: With the coronavirus (COVID-19) pandemic continuing to spread around the globe, there is an unprecedented need to develop different approaches to containing the pandemic from spreading further. One particular case of importance is mass-gathering events. Mass-gathering events have been shown to exhibit the possibility to be superspreader events; as such, the adoption of effective control strategies by policymakers is essential to curb the spread of the pandemic. This paper deals with modeling the possible spread of COVID-19 in the Hajj, the world’s largest religious gathering.
We present an agent-based model (ABM) for two rituals of the Hajj: Tawaf and Ramy al-Jamarat. The model aims to investigate the effect of two control measures: buffers and face masks. We couple these control measures with a third control measure that can be adopted by policymakers, which is limiting the capacity of each ritual. Our findings show the impact of each control measure on the curbing of the spread of COVID-19 under the different crowd dynamics induced by the constraints of each ritual.
... Public masks are the government intervention in South Korea to suppress the surging prices of face masks in the early days of the Covid-19 pandemic. Mask wearing has been shown to prevent respiratory virus transmission, even the Covid-19 virus, 15,16 and there was a heightened awareness of mask-wearing among South Koreans from the prior exposure to SARS-CoV in 2003 and MERS-CoV in 2015. Within a month of the first diagnosed case of Covid-19, the price of KF94 masks nearly quadrupled from the limited production capacity, the market manipulation by some sellers and the subsequent supply shortage. ...
Background:
To control the surging prices of KF94 masks amid the Covid-19 pandemic in South Korea, the government mandated 80% of medical masks to be sold as "public masks" at a fixed price. The mask prices came down quickly, ensuring public health and suppressing the spread of the pandemic, and the sales of KF94 masks reverted to the free market system on July 12, 2020. This paper aims to evaluate the unintended consequence of public masks to mitigate any negative effects for future deployment.
Methods:
The relationship between the offline and online prices of KF94 masks and the production quantity of medical masks was estimated using the data after July 12, 2020 (the "free market" period), and, given the regression results, counterfactual analyses were conducted to predict what the offline and online prices of KF94 masks would have been before July 12, 2020 (the "public masks" period) had the sales of medical masks reverted to the free market system a month earlier than July 12, 2020.
Results:
The prolonged deployment of public masks distorted the ratio of offline and online prices of KF94 masks and kept the prices artificially high at its later stage. How much higher? The online price of privately sold KF94 masks would have been roughly thirty to forty percent lower and the offline price roughly three to four percent lower if public masks ended four weeks earlier.
Conclusion:
The government intervention achieved its intended consequence of controlling the surging prices of KF94 masks at the early days of Covid-19, but the prolonged use of public masks had the unintended consequence of distorting market outcomes. The lesson? The government intervention should be kept brief, and the free market system should return as soon as the crisis subsides.
... Similarly, the Centers for Disease Control and Prevention (CDC) continue to recommend wearing of masks, especially using non-valved multi-layer cloth masks (CDC, 2021). Also, a systematic review and metaanalysis revealed that usage of facemask can reduce the risk of respiratory virus infection by 80% (Liang et al., 2020).People with asymptomatic or pre-symptomatic of COVID-19 are more strongly advised to wear masks because these people have 50% of possibility to transmit the virus to other people (Johansson et al., 2021;Moghadas et al., 2020). ...
Background: While the COVID-19 pandemic has spread across nations in significant terms, midwives who play a crucial role in offering maternal and child care amid the pandemic stand a high risk of being infected. Examining their level of compliance with the standard precautions amid the pandemic is important.
Purpose: To assess the level of compliance of midwives in Indonesia with Personal Protective Equipment (PPE) usage and hand washing.
Methods: In June 2020, an online cross-sectional survey was conducted on 1520 midwives in Indonesia during the early onset of the COVID-19 pandemic. Data were analyzed using Statistical Package for the Social Sciences version 26. Association between demographic variables and compliance with standard precautions was measured using Chi-square test.
Results: Approximately 74% of midwives used PPE and masks when outside while more than 40% of them did not always wash their hands after they touch an object outside home. A significant association was found between level of education (p =.001), region (p =.000) and mask usage. However, association between ethnicity and mask usage; region and handwashing were not sign ificant.
Conclusion: Majority of the midwives in Indonesia complied with PPE usage, but majority did not adhere to hand washing. This highlights the need for appropriate interventions to improve compliance to standard precautions in a bid to curtail further spread of the pandemic
Background:
While increased face mask use has helped reduce COVID-19 transmission, there have been concerns about its influence on thermoregulation during exercise in the heat, but consistent, evidence-based recommendations are lacking.
Hypothesis:
No physiological differences would exist during low-to-moderate exercise intensity in the heat between trials with and without face masks, but perceptual sensations could vary.
Study design:
Crossover study.
Level of evidence:
Level 2.
Methods:
Twelve physically active participants (8 male, 4 female; age = 24 ± 3 years) completed 4 face mask trials and 1 control trial (no mask) in the heat (32.3°C ± 0.04°C; 54.4% ± 0.7% relative humidity [RH]). The protocol was 60 minutes of walking and jogging between 35% and 60% of relative VO2max. Rectal temperature (Trec), heart rate (HR), temperature and humidity inside and outside of the face mask (Tmicro_in, Tmicro_out, RHmicro_in, RHmicro_out) and perceptual variables (rating of perceived exertion (RPE), thermal sensation, thirst sensation, fatigue level, and overall breathing discomfort) were monitored throughout all trials.
Results:
Mean Trec and HR increased at 30- and 60-minute time points compared with 0-minute time points, but no difference existed between face mask trials and control trials (P > 0.05). Mean Tmicro_in, RHmicro_in, and humidity difference inside and outside of the face mask (ΔRHmicro) were significantly different between face mask trials (P < 0.05). There was no significant difference in perceptual variables between face mask trials and control trials (P > 0.05), except overall breathing discomfort (P < 0.01). Higher RHmicro_in, RPE, and thermal sensation significantly predicted higher overall breathing discomfort (r2 = 0.418; P < 0.01).
Conclusion:
Face mask use during 60 minutes of low-to-moderate exercise intensity in the heat did not significantly affect Trec or HR. Although face mask use may affect overall breathing discomfort due to the changes in the face mask microenvironment, face mask use itself did not cause an increase in whole body thermal stress.
Clinical relevance:
Face mask use is feasible and safe during exercise in the heat, at low-to-moderate exercise intensities, for physically active, healthy individuals.
Background
To limit the spread of the new coronavirus disease 2019 (COVID-19), the World Health Organization recommends the use of face mask as a part of the pandemic control strategy. It has published also “best practices” in which it advises to avoid touching the mask while wearing it. This might be challenging. The purpose of this study was to investigate the frequency of mask-touching behavior in public transportation.
Methods
Observational study using data collected in real life. This survey was conducted in subways and local trains of the greater Paris region, France, between May 4th and 25th, 2020. Public Transportation users were covertly observed. Demographic characteristics, type of mask and the main activity were collected by the investigator. The duration of observation, the frequency of touching face mask, hair and the uncovered area of the face were also recorded. Frequency of mask-touching per hour was determined.
Results
One hundred eighty two persons were observed. The median of estimated age [1st and 3rd interquartile] was 35 [30;45] years and 87 (48%) were women. One hundred forty three (79%) were wearing surgical mask. The median time of observation was 8 [4;12] minutes. During this period, 87 (48%) persons touched their mask 15 [7.5;30] times per hour of whom only two (8%) have used hydroalcoholic solution to disinfect their hands.
Conclusions
Mask touching is frequent and is rarely followed by hand disinfection. Actions regarding mask use should be taken to improve compliance.
We introduce J une , an open-source framework for the detailed simulation of epidemics on the basis of social interactions in a virtual population constructed from geographically granular census data, reflecting age, sex, ethnicity and socio-economic indicators. Interactions between individuals are modelled in groups of various sizes and properties, such as households, schools and workplaces, and other social activities using social mixing matrices. J une provides a suite of flexible parametrizations that describe infectious diseases, how they are transmitted and affect contaminated individuals. In this paper, we apply J une to the specific case of modelling the spread of COVID-19 in England. We discuss the quality of initial model outputs which reproduce reported hospital admission and mortality statistics at national and regional levels as well as by age strata.
Background
COVID-19 outbreaks have occurred in homeless shelters across the US, highlighting an urgent need to identify the most effective infection control strategy to prevent future outbreaks.
Methods
We developed a microsimulation model of SARS-CoV-2 transmission in a homeless shelter and calibrated it to data from cross-sectional polymerase chain reaction (PCR) surveys conducted during COVID-19 outbreaks in five homeless shelters in three US cities from March 28 to April 10, 2020. We estimated the probability of averting a COVID-19 outbreak when an exposed individual is introduced into a representative homeless shelter of 250 residents and 50 staff over 30 days under different infection control strategies, including daily symptom-based screening, twice-weekly PCR testing, and universal mask wearing.
Results
The proportion of PCR-positive residents and staff at the shelters with observed outbreaks ranged from 2.6 to 51.6%, which translated to the basic reproduction number ( R 0 ) estimates of 2.9–6.2. With moderate community incidence (~ 30 confirmed cases/1,000,000 people/day), the estimated probabilities of averting an outbreak in a low-risk ( R 0 = 1.5), moderate-risk ( R 0 = 2.9), and high-risk ( R 0 = 6.2) shelter were respectively 0.35, 0.13, and 0.04 for daily symptom-based screening; 0.53, 0.20, and 0.09 for twice-weekly PCR testing; 0.62, 0.27, and 0.08 for universal masking; and 0.74, 0.42, and 0.19 for these strategies in combination. The probability of averting an outbreak diminished with higher transmissibility ( R 0 ) within the simulated shelter and increasing incidence in the local community.
Conclusions
In high-risk homeless shelter environments and locations with high community incidence of COVID-19, even intensive infection control strategies (incorporating daily symptom screening, frequent PCR testing, and universal mask wearing) are unlikely to prevent outbreaks, suggesting a need for non-congregate housing arrangements for people experiencing homelessness. In lower-risk environments, combined interventions should be employed to reduce outbreak risk.
Purpose:
This study analyzed the current status of face mask usage. It also identified factors related to the knowledge and behavior regarding the same among older adults living alone during the COVID-19 pandemic.
Methods:
This descriptive study was conducted via a telephone survey involving 283 older adults living alone in S City from March to April 2020. Knowledge and behavior pertaining to face mask usage were measured using Hilda Ho's Face Mask Use Scale; reliability of the measurement was Kuder-Richardson formula-20 = .62, Cronbach's α = .92. Data were analyzed using descriptive analysis, independent t-test, Pearson's correlation coefficient, and multiple linear regression.
Results:
Older adults used one mask for 3.55 days on an average. The knowledge level was 9.97 (± 1.84) out of 12 and behavior level was 15.49 (± 1.55) out of 16. Level of education (β = - .31, p < .001), living region (β = .13, p = .017), personal income (β = .12, p = .041) significantly affected the face mask usage-related knowledge, and living region (β = .15, p = .010) significantly affected the face mask usage-related behavior.
Conclusion:
Older adults living alone are aware of the effects of using face masks. However, their mask usage is inappropriate, for example, the prolonged use of the same mask. Considering the low level of face mask usage-related knowledge, it is necessary to develop customized education programs and infectious disease prevention strategies for older adults possessing low educational levels living alone in urban-rural complex areas.
Roy, Steven, Inigo Soteras, Alison Sheets, Richard Price, Kazue Oshiro, Simon Rauch, Don McPhalen, Maria Antonia Nerin, Giacomo Strapazzon, Myron Allen, Alistair Read, and Peter Paal. Guidelines for mountain rescue during the COVID-19 pandemic: official guidelines of the International Commission for Alpine Rescue. High Alt Med Biol. 22: 128-141, 2021. Background: In mountain rescue, uncertainty exists on the best practice to prevent coronavirus disease 2019 (COVID-19) transmission. The aim of this work was to provide a state-of-the-art overview of the challenges caused by the COVID-19 pandemic in mountain rescue. Methods: Original articles or reviews, published until December 27, 2020 in Cochrane COVID-19 Study Register, EMBASE, PubMed, and Google Scholar were included. Articles were limited to English, French, German, or Spanish with the article topic COVID-19 or other epidemics, addressing transmission, transport, rescue, or cardiopulmonary resuscitation. Results: The literature search yielded 6,190 articles. A total of 952 were duplicates and 5,238 were unique results. After exclusion of duplicates and studies that were not relevant to this work, 249 articles were considered for this work. Finally, 72 articles and other sources were included. Conclusions: Recommendations are provided for protection of the rescuer (including screening, personal protective equipment [PPE], and vaccination), protection of the patient (including general masking if low risk, specific PPE if high risk), equipment hygiene (including disinfection after every mission), use of single-use products, training and medical measures under COVID-19 precautions, and psychological wellbeing of rescuers during the COVID-19 pandemic. Adapted COVID-19 precautions for low-and-medium-income countries are also discussed.
COVID-19 is the most severe pandemic globally since the 1918 influenza pandemic. Effectively responding to this once-in-a-century global pandemic is a worldwide challenge that the international community needs to jointly face and solve. This study reviews and discusses the key measures taken by major countries in 2020 to fight against COVID-19, such as lockdowns, social distancing, wearing masks, hand hygiene, using Fangcang shelter hospitals, large-scale nucleic acid testing, close-contacts tracking, and pandemic information monitoring, as well as their prevention and control effects. We hope it can help improve the efficiency and effectiveness of pandemic prevention and control in future.
Objective
The academic and scientific community has reacted at pace to gather evidence to help and inform about COVID-19. Concerns have been raised about the quality of this evidence. The aim of this review was to map the nature, scope and quality of evidence syntheses on COVID-19 and to explore the relationship between review quality and the extent of researcher, policy and media interest.
Design and setting
A meta-research: systematic review of reviews.
Information sources
PubMed, Epistemonikos COVID-19 evidence, the Cochrane Library of Systematic Reviews, the Cochrane COVID-19 Study Register, EMBASE, CINAHL, Web of Science Core Collection and the WHO COVID-19 database, searched between 10 June 2020 and 15 June 2020.
Eligibility criteria
Any peer-reviewed article reported as a systematic review, rapid review, overview, meta-analysis or qualitative evidence synthesis in the title or abstract addressing a research question relating to COVID-19. Articles described as meta-analyses but not undertaken as part of a systematic or rapid review were excluded.
Study selection and data extraction
Abstract and full text screening were undertaken by two independent reviewers. Descriptive information on review type, purpose, population, size, citation and attention metrics were extracted along with whether the review met the definition of a systematic review according to six key methodological criteria. For those meeting all criteria, additional data on methods and publication metrics were extracted.
Risk of bias
For articles meeting all six criteria required to meet the definition of a systematic review, AMSTAR-2 ((A MeaSurement Tool to Assess systematic Reviews, version 2.0) was used to assess the quality of the reported methods.
Results
2334 articles were screened, resulting in 280 reviews being included: 232 systematic reviews, 46 rapid reviews and 2 overviews. Less than half reported undertaking critical appraisal and a third had no reproducible search strategy. There was considerable overlap in topics, with discordant findings. Eighty-eight of the 280 reviews met all six systematic review criteria. Of these, just 3 were rated as of moderate or high quality on AMSTAR-2, with the majority having critical flaws: only a third reported registering a protocol, and less than one in five searched named COVID-19 databases. Review conduct and publication were rapid, with 52 of the 88 systematic reviews reported as being conducted within 3 weeks, and a half published within 3 weeks of submission. Researcher and media interest, as measured by altmetrics and citations, was high, and was not correlated with quality.
Discussion
This meta-research of early published COVID-19 evidence syntheses found low-quality reviews being published at pace, often with short publication turnarounds. Despite being of low quality and many lacking robust methods, the reviews received substantial attention across both academic and public platforms, and the attention was not related to the quality of review methods.
Interpretation
Flaws in systematic review methods limit the validity of a review and the generalisability of its findings. Yet, by being reported as ‘systematic reviews’, many readers may well regard them as high-quality evidence, irrespective of the actual methods undertaken. The challenge especially in times such as this pandemic is to provide indications of trustworthiness in evidence that is available in ‘real time’.
PROSPERO registration number
CRD42020188822.
The exact risk association of coronavirus disease 2019 (COVID-19) for surgeons is not quantified which may be affected by their risk of exposure and individual factors. The objective of this review is to quantify the risk of COVID-19 among surgeons, and explore whether facemask can minimise the risk of COVID-19 among surgeons. A systematised review was carried out by searching MEDLINE to locate items on severe acute respiratory syndrome coronavirus 2 or COVID-19 in relation to health care workers (HCWs) especially those work in surgical specialities including surgical nurses and intensivists. Additionally, systematic reviews that assessed the effectiveness of facemask against viral respiratory infections, including COVID-19, among HCWs were identified. Data from identified articles were abstracted, synthesised and summarised. Fourteen primary studies that provided data on severe acute respiratory syndrome coronavirus 2 infection or experience among surgeons and 11 systematic reviews that provided evidence of the effectiveness of facemask (and other personal protective equipment) were summarised. Although the risk of COVID-19 could not be quantified precisely among surgeons, about 14% of HCWs including surgeons had COVID-19, there could be variations depending on settings. Facemask was found to be somewhat protective against COVID-19, but the HCWs’ compliance was highly variable ranging from zero to 100%. Echoing surgical societies’ guidelines we continue to recommend facemask use among surgeons to prevent COVID-19. ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
Background:
Sociodemographic variables may impact people safety measure decisions. The use/choice (or not) of adequate face masks could help to decrease the spread of the COVID-19 infection and be a safety and health measure.
Objective:
To study sociodemographic variables and COVID-19 aspects which could impact the decision and/or choice to use (or not) face masks in the prevention and care for a possible COVID-19 infection among a large sample of young and elderly Brazilian people.
Methods:
An online survey composed by 14 items with closed questions about the sociodemographic variables and questions about COVID-19 was applied. Our sample (n=2,673) consisted of Brazilian people (≥ 18 years) from different States of Brazil. To compare the variables of interest (associated with wear face mask or not), Chi-square and Likelihood Ratio test was used (p-value <0.05).
Results:
Most of the participants, of both groups (≤59 and ≥ 60 years old) were women from Southeast region and postgraduate. Approximately 61% of individuals aged ≤59 years and 67.8% of those aged ≥ 60 years were not health professionals. In the group aged ≤59 years, 83.4% refered COVID-19 signs and symptoms and 97.3% refered not having been COVID-19 diagnosed. In the group aged ≥ 60 years, 92.5% refered signs and symptoms of COVID-19 and 98.3% have been diagnosed with the disease. Majority of the participants, for both groups, reported the use of face masks. The use of facial masks was influenced by sex, level of education, and whether the participant was a health professional or not.
Conclusions:
Young and older adults report to wear face mask during the COVID-19 outbreak. It is difficult to measure how much this attitude, habit, and behavior could have a positive impact on the degree of infection and spread of the disease. However, it can be a positive indicator of adherence to the population's security and safety measures during COVID-19 outbreak.
Clinicaltrial:
Background
The coronavirus disease 2019 (COVID-19) pandemic has led to personal protective equipment (PPE) shortages, requiring mask reuse or improvisation. We provide a review of medical-grade facial protection (surgical masks, N95 respirators and face shields) for healthcare workers, the safety and efficacy of decontamination methods, and the utility of alternative strategies in emergency shortages or resource-scarce settings.
Methods
We conducted a scoping review of PubMed and grey literature related to facial protection and potential adaptation strategies in the setting of PPE shortages (January 2000 to March 2020). Limitations included few COVID-19-specific studies and exclusion of non-English language articles. We conducted a narrative synthesis of the evidence based on relevant healthcare settings to increase practical utility in decision-making.
Results
We retrieved 5462 peer-reviewed articles and 41 grey literature records. In total, we included 67 records which met inclusion criteria. Compared with surgical masks, N95 respirators perform better in laboratory testing, may provide superior protection in inpatient settings and perform equivalently in outpatient settings. Surgical mask and N95 respirator conservation strategies include extended use, reuse or decontamination, but these strategies may result in inferior protection. Limited evidence suggests that reused and improvised masks should be used when medical-grade protection is unavailable.
Conclusion
The COVID-19 pandemic has led to critical shortages of medical-grade PPE. Alternative forms of facial protection offer inferior protection. More robust evidence is required on different types of medical-grade facial protection. As research on COVID-19 advances, investigators should continue to examine the impact on alternatives of medical-grade facial protection.
There were 3 influenza pandemics in the 20th century, and there has been 1 so far in the 21st century. Local, national, and international health authorities regularly update their plans for mitigating the next influenza pandemic in light of the latest available evidence on the effectiveness of various control measures in reducing transmission. Here, we review the evidence base on the effectiveness of nonpharmaceutical personal protective measures and environmental hygiene measures in nonhealthcare settings and discuss their potential inclusion in pandemic plans. Although mechanistic studies support the potential effect of hand hygiene or face masks, evidence from 14 randomized controlled trials of these measures did not support a substantial effect on transmission of laboratory-confirmed influenza. We similarly found limited evidence on the effectiveness of improved hygiene and environmental cleaning. We identified several major knowledge gaps requiring further research, most fundamentally an improved characterization of the modes of person-to-person transmission.
The ongoing COVID-19 outbreak has spread rapidly on a global scale. While the transmission of SARS-CoV-2 via human respiratory droplets and direct contact is clear, the potential for aerosol transmission is poorly understood1–3. This study investigated the aerodynamic nature of SARS-CoV-2 by measuring viral RNA in aerosols in different areas of two Wuhan hospitals during the COVID-19 outbreak in February and March 2020. The concentration of SARS-CoV-2 RNA in aerosols detected in isolation wards and ventilated patient rooms was very low, but it was elevated in the patients’ toilet areas. Levels of airborne SARS-CoV-2 RNA in the majority of public areas was undetectable except in two areas prone to crowding, possibly due to infected carriers in the crowd. We found that some medical staff areas initially had high concentrations of viral RNA with aerosol size distributions showing peaks in submicrometre and/or supermicrometre regions, but these levels were reduced to undetectable levels after implementation of rigorous sanitization procedures. Although we have not established the infectivity of the virus detected in these hospital areas, we propose that SARS-CoV-2 may have the potential to be transmitted via aerosols. Our results indicate that room ventilation, open space, sanitization of protective apparel, and proper use and disinfection of toilet areas can effectively limit the concentration of SARS-CoV-2 RNA in aerosols. Future work should explore the infectivity of aerosolized virus.
Face mask use by the general public for limiting the spread of the COVID-19 pandemic is controversial, though increasingly recommended, and the potential of this intervention is not well understood. We develop a compartmental model for assessing the community-wide impact of mask use by the general, asymptomatic public, a portion of which may be asymptomatically infectious. Model simulations, using data relevant to COVID-19 dynamics in the US states of New York and Washington, suggest that broad adoption of even relatively ineffective face masks may meaningfully reduce community transmission of COVID-19 and decrease peak hospitalizations and deaths. Moreover, mask use decreases the effective transmission rate in nearly linear proportion to the product of mask effectiveness (as a fraction of potentially infectious contacts blocked) and coverage rate (as a fraction of the general population), while the impact on epidemiologic outcomes (death, hospitalizations) is highly nonlinear, indicating masks could synergize with other non-pharmaceutical measures. Notably, masks are found to be useful with respect to both preventing illness in healthy persons and preventing asymptomatic transmission. Hypothetical mask adoption scenarios, for Washington and New York state, suggest that immediate near universal (80%) adoption of moderately (50%) effective masks could prevent on the order of 17–45% of projected deaths over two months in New York, while decreasing the peak daily death rate by 34–58%, absent other changes in epidemic dynamics. Even very weak masks (20% effective) can still be useful if the underlying transmission rate is relatively low or decreasing: In Washington, where baseline transmission is much less intense, 80% adoption of such masks could reduce mortality by 24–65% (and peak deaths 15–69%), compared to 2–9% mortality reduction in New York (peak death reduction 9–18%). Our results suggest use of face masks by the general public is potentially of high value in curtailing community transmission and the burden of the pandemic. The community-wide benefits are likely to be greatest when face masks are used in conjunction with other non-pharmaceutical practices (such as social-distancing), and when adoption is nearly universal (nation-wide) and compliance is high.
To determine distribution of severe acute respiratory syndrome coronavirus 2 in hospital wards in Wuhan, China, we tested air and surface samples. Contamination was greater in intensive care units than general wards. Virus was widely distributed on floors, computer mice, trash cans, and sickbed handrails and was detected in air ≈4 m from patients.
We identified seasonal human coronaviruses, influenza viruses and rhinoviruses in exhaled breath and coughs of children and adults with acute respiratory illness. Surgical face masks significantly reduced detection of influenza virus RNA in respiratory droplets and coronavirus RNA in aerosols, with a trend toward reduced detection of coronavirus RNA in respiratory droplets. Our results indicate that surgical face masks could prevent transmission of human coronaviruses and influenza viruses from symptomatic individuals.
Importance
In December 2019, novel coronavirus (2019-nCoV)–infected pneumonia (NCIP) occurred in Wuhan, China. The number of cases has increased rapidly but information on the clinical characteristics of affected patients is limited.
Objective
To describe the epidemiological and clinical characteristics of NCIP.
Design, Setting, and Participants
Retrospective, single-center case series of the 138 consecutive hospitalized patients with confirmed NCIP at Zhongnan Hospital of Wuhan University in Wuhan, China, from January 1 to January 28, 2020; final date of follow-up was February 3, 2020.
Exposures
Documented NCIP.
Main Outcomes and Measures
Epidemiological, demographic, clinical, laboratory, radiological, and treatment data were collected and analyzed. Outcomes of critically ill patients and noncritically ill patients were compared. Presumed hospital-related transmission was suspected if a cluster of health professionals or hospitalized patients in the same wards became infected and a possible source of infection could be tracked.
Results
Of 138 hospitalized patients with NCIP, the median age was 56 years (interquartile range, 42-68; range, 22-92 years) and 75 (54.3%) were men. Hospital-associated transmission was suspected as the presumed mechanism of infection for affected health professionals (40 [29%]) and hospitalized patients (17 [12.3%]). Common symptoms included fever (136 [98.6%]), fatigue (96 [69.6%]), and dry cough (82 [59.4%]). Lymphopenia (lymphocyte count, 0.8 × 10⁹/L [interquartile range {IQR}, 0.6-1.1]) occurred in 97 patients (70.3%), prolonged prothrombin time (13.0 seconds [IQR, 12.3-13.7]) in 80 patients (58%), and elevated lactate dehydrogenase (261 U/L [IQR, 182-403]) in 55 patients (39.9%). Chest computed tomographic scans showed bilateral patchy shadows or ground glass opacity in the lungs of all patients. Most patients received antiviral therapy (oseltamivir, 124 [89.9%]), and many received antibacterial therapy (moxifloxacin, 89 [64.4%]; ceftriaxone, 34 [24.6%]; azithromycin, 25 [18.1%]) and glucocorticoid therapy (62 [44.9%]). Thirty-six patients (26.1%) were transferred to the intensive care unit (ICU) because of complications, including acute respiratory distress syndrome (22 [61.1%]), arrhythmia (16 [44.4%]), and shock (11 [30.6%]). The median time from first symptom to dyspnea was 5.0 days, to hospital admission was 7.0 days, and to ARDS was 8.0 days. Patients treated in the ICU (n = 36), compared with patients not treated in the ICU (n = 102), were older (median age, 66 years vs 51 years), were more likely to have underlying comorbidities (26 [72.2%] vs 38 [37.3%]), and were more likely to have dyspnea (23 [63.9%] vs 20 [19.6%]), and anorexia (24 [66.7%] vs 31 [30.4%]). Of the 36 cases in the ICU, 4 (11.1%) received high-flow oxygen therapy, 15 (41.7%) received noninvasive ventilation, and 17 (47.2%) received invasive ventilation (4 were switched to extracorporeal membrane oxygenation). As of February 3, 47 patients (34.1%) were discharged and 6 died (overall mortality, 4.3%), but the remaining patients are still hospitalized. Among those discharged alive (n = 47), the median hospital stay was 10 days (IQR, 7.0-14.0).
Conclusions and Relevance
In this single-center case series of 138 hospitalized patients with confirmed NCIP in Wuhan, China, presumed hospital-related transmission of 2019-nCoV was suspected in 41% of patients, 26% of patients received ICU care, and mortality was 4.3%.
Background:
An ongoing outbreak of pneumonia associated with a novel coronavirus was reported in Wuhan city, Hubei province, China. Affected patients were geographically linked with a local wet market as a potential source. No data on person-to-person or nosocomial transmission have been published to date.
Methods:
In this study, we report the epidemiological, clinical, laboratory, radiological, and microbiological findings of five patients in a family cluster who presented with unexplained pneumonia after returning to Shenzhen, Guangdong province, China, after a visit to Wuhan, and an additional family member who did not travel to Wuhan. Phylogenetic analysis of genetic sequences from these patients were done.
Findings:
From Jan 10, 2020, we enrolled a family of six patients who travelled to Wuhan from Shenzhen between Dec 29, 2019 and Jan 4, 2020. Of six family members who travelled to Wuhan, five were identified as infected with the novel coronavirus. Additionally, one family member, who did not travel to Wuhan, became infected with the virus after several days of contact with four of the family members. None of the family members had contacts with Wuhan markets or animals, although two had visited a Wuhan hospital. Five family members (aged 36-66 years) presented with fever, upper or lower respiratory tract symptoms, or diarrhoea, or a combination of these 3-6 days after exposure. They presented to our hospital (The University of Hong Kong-Shenzhen Hospital, Shenzhen) 6-10 days after symptom onset. They and one asymptomatic child (aged 10 years) had radiological ground-glass lung opacities. Older patients (aged >60 years) had more systemic symptoms, extensive radiological ground-glass lung changes, lymphopenia, thrombocytopenia, and increased C-reactive protein and lactate dehydrogenase levels. The nasopharyngeal or throat swabs of these six patients were negative for known respiratory microbes by point-of-care multiplex RT-PCR, but five patients (four adults and the child) were RT-PCR positive for genes encoding the internal RNA-dependent RNA polymerase and surface Spike protein of this novel coronavirus, which were confirmed by Sanger sequencing. Phylogenetic analysis of these five patients' RT-PCR amplicons and two full genomes by next-generation sequencing showed that this is a novel coronavirus, which is closest to the bat severe acute respiatory syndrome (SARS)-related coronaviruses found in Chinese horseshoe bats.
Interpretation:
Our findings are consistent with person-to-person transmission of this novel coronavirus in hospital and family settings, and the reports of infected travellers in other geographical regions.
Funding:
The Shaw Foundation Hong Kong, Michael Seak-Kan Tong, Respiratory Viral Research Foundation Limited, Hui Ming, Hui Hoy and Chow Sin Lan Charity Fund Limited, Marina Man-Wai Lee, the Hong Kong Hainan Commercial Association South China Microbiology Research Fund, Sanming Project of Medicine (Shenzhen), and High Level-Hospital Program (Guangdong Health Commission).
The goal of this review was to examine the effectiveness of personal protective measures in preventing pandemic influenza transmission in human populations.
We collected primary studies from Medline, Embase, PubMed, Cochrane Library, CINAHL and grey literature. Where appropriate, random effects meta-analyses were conducted using inverse variance statistical calculations.
Meta-analyses suggest that regular hand hygiene provided a significant protective effect (OR = 0.62; 95% CI 0.52–0.73; I2 = 0%), and facemask use provided a non-significant protective effect (OR = 0.53; 95% CI 0.16–1.71; I2 = 48%) against 2009 pandemic influenza infection. These interventions may therefore be effective at limiting transmission during future pandemics.
PROSPERO Registration: 42016039896.
This systematic review and meta-analysis quantified the protective effect of facemasks and respirators against respiratory infections among healthcare workers. Relevant articles were retrieved from Pubmed, EMBASE, and Web of Science. Meta-analyses were conducted to calculate pooled estimates. Meta-analysis of randomized controlled trials (RCTs) indicated a protective effect of masks and respirators against clinical respiratory illness (CRI) (risk ratio [RR] = 0.59; 95% confidence interval [CI]:0.46-0.77) and influenza-like illness (ILI) (RR = 0.34; 95% CI:0.14-0.82). Compared to masks, N95 respirators conferred superior protection against CRI (RR = 0.47; 95% CI: 0.36-0.62) and laboratory-confirmed bacterial (RR = 0.46; 95% CI: 0.34-0.62), but not viral infections or ILI. Meta-analysis of observational studies provided evidence of a protective effect of masks (OR = 0.13; 95% CI: 0.03-0.62) and respirators (OR = 0.12; 95% CI: 0.06-0.26) against severe acute respiratory syndrome (SARS). This systematic review and meta-analysis supports the use of respiratory protection. However, the existing evidence is sparse and findings are inconsistent within and across studies. Multicentre RCTs with standardized protocols conducted outside epidemic periods would help to clarify the circumstances under which the use of masks or respirators is most warranted.
Background
Respiratory viral infections (RVIs) are frequent complications of hematopoietic stem cell transplant (HSCT). Surgical masks are a simple and inexpensive intervention that may reduce nosocomial spread.
Methods
In this prospective single-center study, we instituted a universal surgical mask policy requiring all individuals with direct contact with HSCT patients to wear a surgical mask, regardless of symptoms or season. The primary endpoint was the incidence of RVIs in the mask period (2010–2014) compared with the premask period (2003–2009).
Results
RVIs decreased from 10.3% (95/920 patients) in the premask period to 4.4% (40/911) in the mask period (P < .001). Significant decreases occurred after both allogeneic (64/378 [16.9%] to 24/289 [8.3%], P = .001) and autologous (31/542 [5.7%] to 16/622 [2.6%], P = .007) transplants. After adjusting for multiple covariates including season and year in a segmented longitudinal analysis, the decrease in RVIs remained significant, with risk of RVI of 0.4 in patients in the mask group compared with the premask group (0.19–0.85, P = .02). In contrast, no decrease was observed during this same period in an adjacent hematologic malignancy unit, which followed the same infection control practices except for the mask policy. The majority of this decrease was in parainfluenza virus 3 (PIV3) (8.3% to 2.2%, P < .001).
Conclusions
Requiring all individuals with direct patient contact to wear a surgical mask is associated with a reduction in RVIs, particularly PIV3, during the most vulnerable period following HSCT.
Background: Conflicting recommendations exist related to which facial protection should be used by health care workers to prevent transmission of acute respiratory infections, including pandemic influenza. We performed a systematic review of both clinical and surrogate exposure data comparing N95 respirators and surgical masks for the prevention of transmissible acute respiratory infections.
Methods: We searched various electronic databases and the grey literature for relevant studies published from January 1990 to December 2014. Randomized controlled trials (RCTs), cohort studies and case–control studies that included data on health care workers wearing N95 respirators and surgical masks to prevent acute respiratory infections were included in the metaanalysis. Surrogate exposure studies comparing N95 respirators and surgical masks using manikins or adult volunteers under simulated conditions were summarized separately. Outcomes from clinical studies were laboratory-confirmed respiratory infection, influenza-like illness and workplace absenteeism. Outcomes from surrogate exposure studies were filter penetration, face-seal leakage and total inward leakage.
Results: We identified 6 clinical studies (3 RCTs, 1 cohort study and 2 case–control studies) and 23 surrogate exposure studies. In the meta-analysis of the clinical studies, we found no significant difference between N95 respirators and surgical masks in associated risk of (a) laboratory-confirmed respiratory infection (RCTs: odds ratio [OR] 0.89, 95% confidence interval [CI] 0.64–1.24; cohort study: OR 0.43, 95% CI 0.03–6.41; case–control studies: OR 0.91, 95% CI 0.25–3.36); (b) influenza-like illness (RCTs: OR 0.51, 95% CI 0.19–1.41); or (c) reported workplace absenteeism (RCT: OR 0.92, 95% CI 0.57– 1.50). In the surrogate exposure studies, N95 respirators were associated with less filter penetration, less face-seal leakage and less total inward leakage under laboratory experimental conditions, compared with surgical masks.
Interpretation: Although N95 respirators appeared to have a protective advantage over surgical masks in laboratory settings, our meta-analysis showed that there were insufficient data to determine definitively whether N95 respirators are superior to surgical masks in protecting health care workers against transmissible acute respiratory infections in clinical settings.
This study examined homemade masks as an alternative to commercial face masks.
Several household materials were evaluated for the capacity to block bacterial and viral aerosols. Twenty-one healthy volunteers made their own face masks from cotton t-shirts; the masks were then tested for fit. The number of microorganisms isolated from coughs of healthy volunteers wearing their homemade mask, a surgical mask, or no mask was compared using several air-sampling techniques.
The median-fit factor of the homemade masks was one-half that of the surgical masks. Both masks significantly reduced the number of microorganisms expelled by volunteers, although the surgical mask was 3 times more effective in blocking transmission than the homemade mask.
Our findings suggest that a homemade mask should only be considered as a last resort to prevent droplet transmission from infected individuals, but it would be better than no protection. (Disaster Med Public Health Preparedness. 2013;0:1-6).
In response to several influenza A(H1N1)pdm09 infections that developed in passengers after they traveled on the same 2 flights from New York, New York, USA, to Hong Kong, China, to Fuzhou, China, we assessed transmission of influenza A(H1N1)pdm09 virus on these flights. We defined a case of infection as onset of fever and respiratory symptoms and detection of virus by PCR in a passenger or crew member of either flight. Illness developed only in passengers who traveled on the New York to Hong Kong flight. We compared exposures of 9 case-passengers with those of 32 asymptomatic control-passengers. None of the 9 case-passengers, compared with 47% (15/32) of control-passengers, wore a face mask for the entire flight (odds ratio 0, 95% CI 0-0.71). The source case-passenger was not identified. Wearing a face mask was a protective factor against influenza infection. We recommend a more comprehensive intervention study to accurately estimate this effect.
Limited vaccine availability and the potential for resistance to antiviral medications have led to calls for establishing the efficacy of non-pharmaceutical measures for mitigating pandemic influenza. Our objective was to examine if the use of face masks and hand hygiene reduced rates of influenza-like illness (ILI) and laboratory-confirmed influenza in the natural setting. A cluster-randomized intervention trial was designed involving 1,178 young adults living in 37 residence houses in 5 university residence halls during the 2007–2008 influenza season. Participants were assigned to face mask and hand hygiene, face mask only, or control group during the study. Discrete-time survival models using generalized estimating equations to estimate intervention effects on ILI and confirmed influenza A/B infection over a 6-week study period were examined. A significant reduction in the rate of ILI was observed in weeks 3 through 6 of the study, with a maximum reduction of 75% during the final study week (rate ratio [RR] = 0.25, [95% CI, 0.07 to 0.87]). Both intervention groups compared to the control showed cumulative reductions in rates of influenza over the study period, although results did not reach statistical significance. Generalizability limited to similar settings and age groups. Face masks and hand hygiene combined may reduce the rate of ILI and confirmed influenza in community settings. These non-pharmaceutical measures should be recommended in crowded settings at the start of an influenza pandemic.
Trail Registration
Clinicaltrials.gov NCT00490633
Previous controlled studies on the effect of non-pharmaceutical interventions (NPI) - namely the use of facemasks and intensified hand hygiene - in preventing household transmission of influenza have not produced definitive results. We aimed to investigate efficacy, acceptability, and tolerability of NPI in households with influenza index patients.
We conducted a cluster randomized controlled trial during the pandemic season 2009/10 and the ensuing influenza season 2010/11. We included households with an influenza positive index case in the absence of further respiratory illness within the preceding 14 days. Study arms were wearing a facemask and practicing intensified hand hygiene (MH group), wearing facemasks only (M group) and none of the two (control group). Main outcome measure was laboratory confirmed influenza infection in a household contact. We used daily questionnaires to examine adherence and tolerability of the interventions.
We recruited 84 households (30 control, 26 M and 28 MH households) with 82, 69 and 67 household contacts, respectively. In 2009/10 all 41 index cases had a influenza A (H1N1) pdm09 infection, in 2010/11 24 had an A (H1N1) pdm09 and 20 had a B infection. The total secondary attack rate was 16% (35/218). In intention-to-treat analysis there was no statistically significant effect of the M and MH interventions on secondary infections. When analysing only households where intervention was implemented within 36 h after symptom onset of the index case, secondary infection in the pooled M and MH groups was significantly lower compared to the control group (adjusted odds ratio 0.16, 95% CI, 0.03-0.92). In a per-protocol analysis odds ratios were significantly reduced among participants of the M group (adjusted odds ratio, 0.30, 95% CI, 0.10-0.94). With the exception of MH index cases in 2010/11 adherence was good for adults and children, contacts and index cases.
Results suggest that household transmission of influenza can be reduced by the use of NPI, such as facemasks and intensified hand hygiene, when implemented early and used diligently. Concerns about acceptability and tolerability of the interventions should not be a reason against their recommendation.
The study was registered with ClinicalTrials.gov (Identifier NCT00833885).
Influenza infections may result in different clinical presentations. This study aims to determine the clinical differences between circulating influenza strains in a young healthy adult population in the tropics.
A febrile respiratory illness (FRI) (fever ≥ 37.5°C with cough and/or sore throat) surveillance program was started in 4 large military camps in Singapore on May 2009. Personnel with FRI who visited the camp clinics from 11 May 2009 to 25 June 2010 were recruited. Nasal washes and interviewer-administered questionnaires on demographic information and clinical features were obtained from consenting participants. All personnel who tested positive for influenza were included in the study. Overall symptom load was quantified by counting the symptoms or signs, and differences between strains evaluated using linear models.
There were 434 (52.9%) pandemic H1N1-2009, 58 (7.1%) seasonal H3N2, 269 (32.8%) influenza B, and 10 (1.2%) seasonal H1N1 cases. Few seasonal influenza A (H1N1) infections were detected and were therefore excluded from analyses, together with undetermined influenza subtypes (44 (1.5%)), or more than 1 co-infecting subtype (6 (0.2%)). Pandemic H1N1-2009 cases had significantly fewer symptoms or signs (mean 7.2, 95%CI 6.9-7.4, difference 1.6, 95%CI 1.2-2.0, p < 0.001) than the other two subtypes (mean 8.7, 95%CI 8.5-9.0). There were no statistical differences between H3N2 and influenza B (p = 0.58). Those with nasal congestion, rash, eye symptoms, injected pharynx or fever were more likely to have H3N2; and those with sore throat, fever, injected pharynx or rhinorrhoea were more likely to have influenza B than H1N1-2009.
Influenza cases have different clinical presentations in the young adult population. Pandemic H1N1 influenza cases had fewer and milder clinical symptoms than seasonal influenza. As we only included febrile cases and had no information on the proportion of afebrile infections, further research is needed to confirm whether the relatively milder presentation of pandemic versus seasonal influenza infections applies to all infections or only febrile illnesses.
Objective: Funnel plots (plots of effect estimates against sample size) may be useful to detect bias in meta-analyses that were later contradicted by large trials. We examined whether a simple test of asymmetry of funnel plots predicts discordance of results when meta-analyses are compared to large trials, and we assessed the prevalence of bias in published meta-analyses. Design: Medline search to identify pairs consisting of a meta-analysis and a single large trial (concordance of results was assumed if effects were in the same direction and the meta-analytic estimate was within 30
In April 2009, 2009 pandemic influenza A (H1N1) (hereafter, pH1N1) virus was identified in California, which caused widespread illness throughout the United States. We evaluated pH1N1 transmission among exposed healthcare personnel (HCP) and assessed the use and effectiveness of personal protective equipment (PPE) early in the outbreak.
Cohort study.
Two hospitals and 1 outpatient clinic in Southern California during March 28-April 24, 2009.
Sixty-three HCP exposed to 6 of the first 8 cases of laboratory-confirmed pH1N1 in the United States.
Baseline and follow-up questionnaires were used to collect demographic, epidemiologic, and clinical data. Paired serum samples were obtained to test for pH1N1-specific antibodies by microneutralization and hemagglutination-inhibition assays. Serology results were compared with HCP work setting, role, and self-reported PPE use.
Possible healthcare-associated pH1N1 transmission was identified in 9 (14%) of 63 exposed HCP; 6 (67%) of 9 seropositive HCP had asymptomatic infection. The highest attack rates occurred among outpatient HCP (6/19 [32%]) and among allied health staff (eg, technicians; 8/33 [24%]). Use of mask or N95 respirator was associated with remaining seronegative (P = .047). Adherence to PPE recommendations for preventing transmission of influenza virus and other respiratory pathogens was inadequate, particularly in outpatient settings.
pH1N1 transmission likely occurred in healthcare settings early in the pandemic associated with inadequate PPE use. Organizational support for a comprehensive approach to infectious hazards, including infection prevention training for inpatient- and outpatient-based HCP, is essential to improve HCP and patient safety.
Few data are available about the effectiveness of nonpharmaceutical interventions for preventing influenza virus transmission.
To investigate whether hand hygiene and use of facemasks prevents household transmission of influenza.
Cluster randomized, controlled trial. Randomization was computer generated; allocation was concealed from treating physicians and clinics and implemented by study nurses at the time of the initial household visit. Participants and personnel administering the interventions were not blinded to group assignment. (ClinicalTrials.gov registration number: NCT00425893)
Households in Hong Kong.
407 people presenting to outpatient clinics with influenza-like illness who were positive for influenza A or B virus by rapid testing (index patients) and 794 household members (contacts) in 259 households.
Lifestyle education (control) (134 households), hand hygiene (136 households), or surgical facemasks plus hand hygiene (137 households) for all household members.
Influenza virus infection in contacts, as confirmed by reverse-transcription polymerase chain reaction (RT-PCR) or diagnosed clinically after 7 days.
Sixty (8%) contacts in the 259 households had RT-PCR-confirmed influenza virus infection in the 7 days after intervention. Hand hygiene with or without facemasks seemed to reduce influenza transmission, but the differences compared with the control group were not significant. In 154 households in which interventions were implemented within 36 hours of symptom onset in the index patient, transmission of RT-PCR-confirmed infection seemed reduced, an effect attributable to fewer infections among participants using facemasks plus hand hygiene (adjusted odds ratio, 0.33 [95% CI, 0.13 to 0.87]). Adherence to interventions varied.
The delay from index patient symptom onset to intervention and variable adherence may have mitigated intervention effectiveness.
Hand hygiene and facemasks seemed to prevent household transmission of influenza virus when implemented within 36 hours of index patient symptom onset. These findings suggest that nonpharmaceutical interventions are important for mitigation of pandemic and interpandemic influenza.
Centers for Disease Control and Prevention.
Cases of severe acute respiratory syndrome (SARS) were investigated for SARS coronavirus (SARS-CoV) through RNA tests, serologic response, and viral culture. Of 537 specimens from patients in whom SARS was clinically diagnosed, 332 (60%) had SARS-CoV RNA in one or more clinical specimens, compared with 1 (0.3%) of 332 samples from controls. Of 417 patients with clinical SARS from whom paired serum samples were available, 92% had an antibody response. Rates of viral RNA positivity increased progressively and peaked at day 11 after onset of illness. Although viral RNA remained detectable in respiratory secretions and stool and urine specimens for >30 days in some patients, virus could not be cultured after week 3 of illness. Nasopharyngeal aspirates, throat swabs, or sputum samples were the most useful clinical specimens in the first 5 days of illness, but later in the illness viral RNA could be detected more readily in stool specimens.
To determine factors that predispose or protect healthcare workers from severe acute respiratory syndrome (SARS), we conducted a retrospective cohort study among 43 nurses who worked in two Toronto critical care units with SARS patients. Eight of 32 nurses who entered a SARS patient's room were infected. The probability of SARS infection was 6% per shift worked. Assisting during intubation, suctioning before intubation, and manipulating the oxygen mask were high-risk activities. Consistently wearing a mask (either surgical or particulate respirator type N95) while caring for a SARS patient was protective for the nurses, and consistent use of the N95 mask was more protective than not wearing a mask. Risk was reduced by consistent use of a surgical mask, but not significantly. Risk was lower with consistent use of a N95 mask than with consistent use of a surgical mask. We conclude that activities related to intubation increase SARS risk and use of a mask (particularly a N95 mask) is protective.
Most cases of severe acute respiratory syndrome (SARS) have occurred in close contacts of SARS patients. However, in Beijing, a large proportion of SARS cases occurred in persons without such contact. We conducted a case-control study in Beijing that compared exposures of 94 unlinked, probable SARS patients with those of 281 community-based controls matched for age group and sex. Case-patients were more likely than controls to have chronic medical conditions or to have visited fever clinics (clinics at which possible SARS patients were separated from other patients), eaten outside the home, or taken taxis frequently. The use of masks was strongly protective. Among 31 case-patients for whom convalescent-phase (>21 days) sera were available, 26% had immunoglobulin G to SARS-associated coronavirus. Our finding that clinical SARS was associated with visits to fever clinics supports Beijing's strategy of closing clinics with poor infection-control measures. Our finding that mask use lowered the risk for disease supports the community's use of this strategy.
Between 1 and 22 March 2003, a nosocomial outbreak of Severe Acute Respiratory Syndrome (SARS) occurred at the Communicable Disease Centre in Tan Tock Seng Hospital, Singapore, the national treatment and isolation facility for patients with SARS. A case-control study with 36 cases and 50 controls was conducted of factors associated with the transmission of SARS within the hospital. In univariate analysis, contact with respiratory secretions elevated the odds ratio to 6.9 (95 % CI 1.4-34.6, P= 0.02). Protection was conferred by hand washing (OR 0.06, 95% CI 0.007-0.5, P=0.03) and wearing of N95 masks (OR 0.1, 95% CI 0.03-0.4, P=0.001). Use of gloves and gowns had no effect. Multivariate analysis confirmed the strong role of contact with respiratory secretions (adjusted OR 21.8, 95 % CI 1.7 274.8, P=0.017). Both hand washing (adjusted OR 0.07, 95 % CI 0.008-0.66, P=0.02) and wearing of N95 masks (adjusted OR 0.1, 95% CI 0.02-0.86, P=0.04) remained strongly protective but gowns and gloves had no effect.
To study the factors in relation to severe acute respiratory syndromes (SARS) among health care workers and to develop related protective measures.
Case-control study was applied. A standardized questionnaire was used to collect SARS related information for health care workers who had contacted or treated SARS patients. Univariate analysis was conducted using SPSS 10.0 software package and multivariate logistic regression analysis was conducted using SAS 6.12.
Twenty-seven of the 49 factors under study were significantly associated with SARS infection, in which 22 factors were protective, and the other 5 were risk factors. 27 factors were included for multivariate logistic regression analysis. Results showed that six factors as wearing eye glasses, wearing protection gowns, exposure to secrets/mode of contact with SARS patients, types of mask and the working years atc, remained significant association with hospital infection of SARS.
SARS infection in heath care workers was related to many factors during the process of diagnoses and/or treatment. It is recommended that adequate masks, eye-protection and protective gowns should be adopted for heath care workers during the process of clinical diagnoses and treatment of SARS patients.
A case-control study was conducted to examine the relationship between severe acute respiratory syndrome (SARS) and the time-dependent precautionary behaviors taken during an outbreak of SARS in Hanoi French Hospital (HFH), Vietnam. Masks (odds ratio [OR] = 0.3; 95% confidence interval [CI]: 0.1, 0.7) and gowns (OR = 0.2; 95% CI: 0.0, 0.8) appeared to prevent SARS transmission. The proportion of doctors and nurses who undertook each measure significantly improved (chi(2) = 9.8551, P = 0.043) after the onset of secondary cases. The impact of individual behaviors on an outbreak was investigated through mathematical approaches. The reproduction number decreased from 4.1 to 0.7 after notification. The basic reproduction number was estimated, and the use of masks alone was shown to be insufficient in containing an epidemic. Intuitive results obtained by means of stochastic individual-based simulations showed that rapid improvements in behavior and isolation would increase the probability of extinction.
We conducted a study among healthcare workers (HCWs) exposed to patients with severe acute respiratory syndrome (SARS) before infection control measures were instituted. Of all exposed HCWs, 7.5% had asymptomatic SARS-positive cases. Asymptomatic SARS was associated with lower SARS antibody titers and higher use of masks when compared to pneumonic SARS.
To systematically review evidence for the effectiveness of physical interventions to interrupt or reduce the spread of respiratory viruses.
Search strategy of the Cochrane Library, Medline, OldMedline, Embase, and CINAHL, without language restriction, for any intervention to prevent transmission of respiratory viruses (isolation, quarantine, social distancing, barriers, personal protection, and hygiene). Study designs were randomised trials, cohort studies, case-control studies, and controlled before and after studies.
Of 2300 titles scanned 138 full papers were retrieved, including 49 papers of 51 studies. Study quality was poor for the three randomised controlled trials and most of the cluster randomised controlled trials; the observational studies were of mixed quality. Heterogeneity precluded meta-analysis of most data except that from six case-control studies. The highest quality cluster randomised trials suggest that the spread of respiratory viruses into the community can be prevented by intervening with hygienic measures aimed at younger children. Meta-analysis of six case-control studies suggests that physical measures are highly effective in preventing the spread of SARS: handwashing more than 10 times daily (odds ratio 0.45, 95% confidence interval 0.36 to 0.57; number needed to treat=4, 95% confidence interval 3.65 to 5.52); wearing masks (0.32, 0.25 to 0.40; NNT=6, 4.54 to 8.03); wearing N95 masks (0.09, 0.03 to 0.30; NNT=3, 2.37 to 4.06); wearing gloves (0.43, 0.29 to 0.65; NNT=5, 4.15 to 15.41); wearing gowns (0.23, 0.14 to 0.37; NNT=5, 3.37 to 7.12); and handwashing, masks, gloves, and gowns combined (0.09, 0.02 to 0.35; NNT=3, 2.66 to 4.97). The incremental effect of adding virucidals or antiseptics to normal handwashing to decrease the spread of respiratory disease remains uncertain. The lack of proper evaluation of global measures such as screening at entry ports and social distancing prevent firm conclusions being drawn.
Routine long term implementation of some physical measures to interrupt or reduce the spread of respiratory viruses might be difficult but many simple and low cost interventions could be useful in reducing the spread.
This study aimed at determining the protection factors (PFs) provided by N95 filtering facepiece respirators and surgical masks against particles representing bacterial and viral size ranges (aerodynamic size: 0.04-1.3 mum).
The protection levels of N95 filtering facepiece respirators (four models) and surgical masks (three models) were investigated while they were donned by 12 subjects performing the OSHA (US Occupational Safety and Health Administration) fit-testing exercises in a test chamber.
About 29% of N95 respirators and approximately 100% of surgical masks had PFs <10, which is the assigned PF designated for this type of respirator by the OSHA. On average, the PFs of N95 respirators were 8-12 times greater than those of surgical masks. The minimum PFs were observed in the size range of 0.04-0.2 mum. No significant difference in PF results was found between N95 respirators with and without an exhalation valve.
The study indicates that N95 filtering facepiece respirators may not achieve the expected protection level against bacteria and viruses. An exhalation valve on the N95 respirator does not affect the respiratory protection; it appears to be an appropriate alternative to reduce the breathing resistance.
There are sparse data on whether non-pharmaceutical interventions can reduce the spread of influenza. We implemented a study of the feasibility and efficacy of face masks and hand hygiene to reduce influenza transmission among Hong Kong household members.
We conducted a cluster randomized controlled trial of households (composed of at least 3 members) where an index subject presented with influenza-like-illness of <48 hours duration. After influenza was confirmed in an index case by the QuickVue Influenza A+B rapid test, the household of the index subject was randomized to 1) control or 2) surgical face masks or 3) hand hygiene. Households were visited within 36 hours, and 3, 6 and 9 days later. Nose and throat swabs were collected from index subjects and all household contacts at each home visit and tested by viral culture. The primary outcome measure was laboratory culture confirmed influenza in a household contact; the secondary outcome was clinically diagnosed influenza (by self-reported symptoms). We randomized 198 households and completed follow up home visits in 128; the index cases in 122 of those households had laboratory-confirmed influenza. There were 21 household contacts with laboratory confirmed influenza corresponding to a secondary attack ratio of 6%. Clinical secondary attack ratios varied from 5% to 18% depending on case definitions. The laboratory-based or clinical secondary attack ratios did not significantly differ across the intervention arms. Adherence to interventions was variable.
The secondary attack ratios were lower than anticipated, and lower than reported in other countries, perhaps due to differing patterns of susceptibility, lack of significant antigenic drift in circulating influenza virus strains recently, and/or issues related to the symptomatic recruitment design. Lessons learnt from this pilot have informed changes for the main study in 2008.
ClinicalTrials.gov NCT00425893 HKClinicalTrials.com HKCTR-365.
Background
Face mask usage by the healthy population in the community to reduce risk of transmission of respiratory viruses remains controversial. We assessed the effect of community-wide mask usage to control coronavirus disease 2019 (COVID-19) in Hong Kong Special Administrative Region (HKSAR).
Methods
Patients presenting with respiratory symptoms at outpatient clinics or hospital wards were screened for COVID-19 per protocol. Epidemiological analysis was performed for confirmed cases, especially persons acquiring COVID-19 during mask-off and mask-on settings. The incidence of COVID-19 per-million-population in HKSAR with community-wide masking was compared to that of non-mask-wearing countries which are comparable with HKSAR in terms of population density, healthcare system, BCG vaccination and social distancing measures but not community-wide masking. Compliance of face mask usage in the HKSAR community was monitored.
Findings
Within first 100 days (31 December 2019 to 8 April 2020), 961 COVID-19 patients were diagnosed in HKSAR. The COVID-19 incidence in HKSAR (129.0 per-million-population) was significantly lower (p<0.001) than that of Spain (2983.2), Italy (2250.8), Germany (1241.5), France (1151.6), U.S. (1102.8), U.K. (831.5), Singapore (259.8), and South Korea (200.5). The compliance of face mask usage by HKSAR general public was 96.6% (range: 95.7% to 97.2%). We observed 11 COVID-19 clusters in recreational ‘mask-off’ settings compared to only 3 in workplace ‘mask-on’ settings (p = 0.036 by Chi square test of goodness-of-fit).
Conclusion
Community-wide mask wearing may contribute to the control of COVID-19 by reducing virus shedding in saliva and respiratory droplets from individuals with subclinical or mild COVID-19.
During major epidemic outbreaks, demand for health care workers grows even as the extreme pressures they face cause declining availability. We draw on Taiwan's SARS experience to argue that a modified form of Traffic Control Bundling protects health care worker safety and by extension strengthens overall COVID-19 epidemic control.
This systematic review and meta-analysis quantified the protective effect of facemasks and respirators against respiratory infections among healthcare workers. Relevant articles were retrieved from Pubmed, EMBASE, and Web of Science. Meta-analyses were conducted to calculate pooled estimates. Meta-analysis of randomized controlled trials (RCTs) indicated a protective effect of masks and respirators against clinical respiratory illness (CRI) (risk ratio [RR] = 0.59; 95% confidence interval [CI]:0.46-0.77) and influenza-like illness (ILI) (RR = 0.34; 95% CI:0.14-0.82). Compared to masks, N95 respirators conferred superior protection against CRI (RR = 0.47; 95% CI: 0.36-0.62) and laboratory-confirmed bacterial (RR = 0.46; 95% CI: 0.34-0.62), but not viral infections or ILI. Meta-analysis of observational studies provided evidence of a protective effect of masks (OR = 0.13; 95% CI: 0.03-0.62) and respirators (OR = 0.12; 95% CI: 0.06-0.26) against severe acute respiratory syndrome (SARS). This systematic review and meta-analysis supports the use of respiratory protection. However, the existing evidence is sparse and findings are inconsistent within and across studies. Multicentre RCTs with standardized protocols conducted outside epidemic periods would help to clarify the circumstances under which the use of masks or respirators is most warranted. © The Author 2017. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved.
Background:
Respiratory viral infections (RVI) cause significant morbidity and mortality in hospitalized oncology patients. These viruses are easily spread from asymptomatic and/or symptomatic healthcare workers and visitors to immunocompromised patients, and literature review of facemasks for prevention of infection revealed mixed results. The Bone Marrow Transplant (BMT) Quality Assurance (QA) Committee at Mount Sinai began a surgical mask initiative on the BMT unit. The purpose of our initiative was to assess the impact of surgical mask implementation for healthcare workers and visitors on nosocomial RVIs in all patients hospitalized on the BMT unit. We hypothesized that implementing surgical masks would reduce the number of hospital acquired RVI.
Methods:
We performed a retrospective study involving all patients with malignancy hospitalized on the BMT unit for 4 years. During the latter 2 years, all health care workers and visitors were required to wear a surgical mask in every patient room on the BMT unit. Primary endpoint was incidence of RVI after implementation of surgical masks.
Results:
The 2-year incidence of RVI in the pre-mask period was 14 out of a total of 15,001 patient days on the unit vs. 2 out of 15,608 patient days after mask implementation. The difference in incidence of RVI within the 2 time intervals was noted to be statistically significant (P <0.05, 2-proportion z-test).
Conclusions:
Our quality initiative demonstrated that surgical masks are an infection control modality that may provide benefit to oncology/BMT units by decreasing the risk for hospital-acquired RVI. This article is protected by copyright. All rights reserved.
Background With the increase in patient activity during the 2009 H1N1 pandemic, came an associated increase in occupational infections of healthcare workers (HCWs).
Objectives The aim of this study was to examine factors associated with the transmission of pandemic (H1N1) 2009 among HCWs.
Methods A 1:4 matched case–control study by hospital, ward, age, and gender was conducted in HCWs from hospitals in Beijing during February 2010. Cases were diagnosed with pandemic (H1N1) 2009, and controls had neither influenza-like illness nor diagnosis with pandemic (H1N1) 2009 during August 2009 to January 2010. Information during 7 days before symptom onset of case was collected, and controls were queried about the same period.
Results A total of 51 cases identified via National Notifiable Infectious Disease Surveillance System participated in this study. Controls were matched to cases for a total of 255 individuals. About 19·6% (10/51) of cases and 26·0% (53/204) of controls recalled they had conducted a high-risk procedure on a patient with pandemic (H1N1) 2009. 72·5% (37/51) of cases and 71·6% (146/204) of controls stated they wore medical masks in ≥80% of working time. Only 5·9% (3/51) and 36·3% (74/204) of cases and controls, respectively, reported receiving pandemic vaccination. Participants receiving pandemic vaccination had a significantly lower risk of infection during the pandemic (OR = 0·150, 95% CI: 0·047–0·479, P = 0·001). The estimated vaccine effectiveness was 85·0%.
Conclusions We showed a high vaccine effectiveness of the pandemic vaccine and that vaccination was the only factor significantly associated with risk of infection in HCWs.
Please cite this paper as: Chokephaibulkit et al. (2009) Seroprevalence of 2009 H1N1 Virus Infection and Self-Reported Infection Control Practices Among Healthcare Professionals Following the First Outbreak in Bangkok, Thailand. Influenza and Other Respiratory Viruses DOI: 10.1111/irv.12016. A serologic study with simultaneous self-administered questionnaire regarding infection control (IC) practices and other risks of influenza A (H1N1) pdm09 (2009 H1N1) infection was performed approximately 1 month after the first outbreak among frontline healthcare professionals (HCPs). Of 256 HCPs, 33 (13%) were infected. Self-reported adherence to IC practices in >90% of exposure events was 82·1%, 73·8%, and 53·5% for use of hand hygiene, masks, and gloves, respectively. Visiting crowded public places during the outbreak was associated with acquiring infection (OR 3·1, P = 0·019). Amongst nurses, exposure to HCPs with influenza-like illness during the outbreak without wearing a mask was the only identified risk factor for infection (OR = 2·3, P = 0·039).
Evidence is needed on the effectiveness of non-pharmaceutical interventions (NPIs) to reduce influenza transmission.
We studied NPIs in households with a febrile, influenza-positive child. Households were randomized to control, hand washing (HW), or hand washing plus paper surgical face masks (HW + FM) arms. Study nurses conducted home visits within 24 hours of enrollment and on days 3, 7, and 21. Respiratory swabs and serum were collected from all household members and tested for influenza by RT-PCR or serology.
Between April 2008 and August 2009, 991 (16·5%) of 5995 pediatric influenza-like illness patients tested influenza positive. Four hundred and forty-two index children with 1147 household members were enrolled, and 221 (50·0%) were aged <6 years. Three hundred and ninety-seven (89·8%) households reported that the index patient slept in the parents' bedroom. The secondary attack rate was 21·5%, and 56/345 (16·3%; 95% CI 12·4-20·2%) secondary cases were asymptomatic. Hand-washing subjects reported 4·7 washing episodes/day, compared to 4·9 times/day in the HW + FM arm and 3·9 times/day in controls (P = 0·001). The odds ratios (ORs) for secondary influenza infection were not significantly different in the HW arm (OR = 1·20; 95% CI 0·76-1·88; P-0.442), or the HW + FM arm (OR = 1·16; 95% CI .0·74-1·82; P = 0.525).
Influenza transmission was not reduced by interventions to promote hand washing and face mask use. This may be attributable to transmission that occurred before the intervention, poor facemask compliance, little difference in hand-washing frequency between study groups, and shared sleeping arrangements. A prospective study design and a careful analysis of sociocultural factors could improve future NPI studies.
We compared the efficacy of medical masks, N95 respirators (fit tested and non fit tested), in health care workers (HCWs).
A cluster randomized clinical trial (RCT) of 1441 HCWs in 15 Beijing hospitals was performed during the 2008/2009 winter. Participants wore masks or respirators during the entire work shift for 4 weeks. Outcomes included clinical respiratory illness (CRI), influenza-like illness (ILI), laboratory-confirmed respiratory virus infection and influenza. A convenience no-mask/respirator group of 481 health workers from nine hospitals was compared.
The rates of CRI (3·9% versus 6·7%), ILI (0·3% versus 0·6%), laboratory-confirmed respiratory virus (1·4% versus 2·6%) and influenza (0·3% versus 1%) infection were consistently lower for the N95 group compared to medical masks. By intention-to-treat analysis, when P values were adjusted for clustering, non-fit-tested N95 respirators were significantly more protective than medical masks against CRI, but no other outcomes were significant. The rates of all outcomes were higher in the convenience no-mask group compared to the intervention arms. There was no significant difference in outcomes between the N95 arms with and without fit testing. Rates of fit test failure were low. In a post hoc analysis adjusted for potential confounders, N95 masks and hospital level were significant, but medical masks, vaccination, handwashing and high-risk procedures were not.
Rates of infection in the medical mask group were double that in the N95 group. A benefit of respirators is suggested but would need to be confirmed by a larger trial, as this study may have been underpowered. The finding on fit testing is specific to the type of respirator used in the study and cannot be generalized to other respirators.
Australian New Zealand Clinical Trials Registry (ANZCTR), ACTRN: ACTRN12609000257268 (http://www.anzctr.org.au).
After the outbreak of severe acute respiratory syndrome in Hong Kong, the importance of preventing nosocomial transmission of respiratory viruses has become a top priority in infection control. During the containment and early mitigation phases of the swine-origin influenza virus (S-OIV) A H1N1 pandemic, an infection control bundle consisting of multiple coherent measures was organised by our infection control team to minimise nosocomial transmission. This included repeated open staff forum achieving high attendance; early recognition of index cases among inpatients by liberal testing; early relief of sick staff from work; directly observed hand hygiene practice during outbreaks; and monitoring of compliance with infection control practice. During the first 100 days (from 1 May to 8 August 2009) when the first 100 laboratory-confirmed patients with S-OIV and 12 infected healthcare workers (HCWs) were identified, a total of 836 asymptomatic exposed persons (184 patients and 652 HCWs) were required to undergo a seven-day medical surveillance. The infection control nurses monitored them for the onset of symptoms. Four (0.48%) exposed persons (one house officer, two non-clinical staff, and one patient) were virologically confirmed with S-OIV. Not wearing a surgical mask either by the exposed persons during contact with the index cases (4/4 vs 264/832, P=0.010) or vice versa (4/4 vs 300/832, P=0.017, Fisher's exact test) were found to be significant risk factors for nosocomial acquisition of S-OIV.
We assessed the in vivo efficacy of surgical and N95 (respirator) masks to filter reverse transcription-polymerase chain reaction
(RT-PCR)-detectable virus when worn correctly by patients with laboratory-confirmed acute influenza. Of 26 patients with a
clinical diagnosis of influenza, 19 had the diagnosis confirmed by RT-PCR, and 9 went on to complete the study. Surgical and
N95 masks were equally effective in preventing the spread of PCR-detectable influenza.
An adjusted rank correlation test is proposed as a technique for identifying publication bias in a meta-analysis, and its operating characteristics are evaluated via simulations. The test statistic is a direct statistical analogue of the popular "funnel-graph." The number of component studies in the meta-analysis, the nature of the selection mechanism, the range of variances of the effect size estimates, and the true underlying effect size are all observed to be influential in determining the power of the test. The test is fairly powerful for large meta-analyses with 75 component studies, but has only moderate power for meta-analyses with 25 component studies. However, in many of the configurations in which there is low power, there is also relatively little bias in the summary effect size estimate. Nonetheless, the test must be interpreted with caution in small meta-analyses. In particular, bias cannot be ruled out if the test is not significant. The proposed technique has potential utility as an exploratory tool for meta-analysts, as a formal procedure to complement the funnel-graph.
It has been suggested that the quality of clinical trials should be assessed by blinded raters to limit the risk of introducing bias into meta-analyses and systematic reviews, and into the peer-review process. There is very little evidence in the literature to substantiate this. This study describes the development of an instrument to assess the quality of reports of randomized clinical trials (RCTs) in pain research and its use to determine the effect of rater blinding on the assessments of quality. A multidisciplinary panel of six judges produced an initial version of the instrument. Fourteen raters from three different backgrounds assessed the quality of 36 research reports in pain research, selected from three different samples. Seven were allocated randomly to perform the assessments under blind conditions. The final version of the instrument included three items. These items were scored consistently by all the raters regardless of background and could discriminate between reports from the different samples. Blind assessments produced significantly lower and more consistent scores than open assessments. The implications of this finding for systematic reviews, meta-analytic research and the peer-review process are discussed.
To evaluate the effectiveness of personal protective measures of health care workers (HCWs) against severe acute respiratory syndrome (SARS).
A case-control study from ten hospitals in Guangdong, with 180 non-infected and 77 infected staff members that accessed the isolation unit every day, and participated in direct first aid for severe SARS patients. All participants were surveyed about how they were using personal protective equipment (PPE), protective drugs and hygiene habits when caring for patients with SARS. Statistical analysis was done with either chi(2) or Fisher's exact test for univariate analysis, whereas we used forward stepwise selection (Waldesian) for logistic regression.
Univariate analysis showed that mask, gown, gloves, goggles, footwear, "hand-washing and disinfecting", gargle, "membrane protection", "taking shower and changing clothing after work", "avoid from eating and drinking in ward", oseltamivir phospha tall had protective effects (P < 0.05), but stepwise logistic regression showed significant differences for mask (OR = 0.78, 95% CI: 0.60 - 0.99), goggles (OR = 0.20, 95% CI: 0.10 - 0.41) and footwear (OR = 0.58, 95% CI: 0.39 - 0.86). Analysis for linear trend in proportions showed that dose response relationship existed in mask, gown, gloves, goggles, footwear, gargle, "membrane protection" and "taking shower and changing dree after work" (P < 0.01). The attack rate of HCWs who were rescuing severe SARS patients without any PPE was 61.5% (16/26). It seemed that the more the protective measures were used, the higher the protective effect was (P < 0.001), and could reach 100% if mask, gown, gloves, goggles, footwear, "hand-washing and disinfecting" were all used at the same time.
Nosocomial infection of SARS can be prevented effectively by precautions against droplets and personal contact. HCWs must take strict protection according to the guidance of WHO or Chinese MOH and pay attention to personal hygiene.
Severe acute respiratory syndrome (SARS) is a highly infectious disease with a significant morbidity and case fatality. The major clinical features include persistent fever, chills/rigor, myalgia, malaise, dry cough, headache and dyspnoea. Less common symptoms include sputum production, sore throat, coryza, dizziness, nausea, vomiting and diarrhoea. Older subjects may present with decrease in general well-being, poor feeding, fall/fracture and delirium, without the typical febrile response. Common laboratory features include lymphopenia with depletion of CD4 and CD8 lymphocytes, thrombocytopenia, prolonged activated partial thromboplastin time, elevated D-Dimer, elevated alanine transminases, lactate dehydrogenase and creatinine kinase. The constellation of compatible clinical and laboratory findings, together with the rather characteristic radiological features especially on HRCT and the lack of clinical response to broad-spectrum antibiotics, should quickly arouse suspicion of SARS. The positivity rates of urine, nasophargyngeal aspirate and stool specimen have been reported to be 42%, 68% and 97%, respectively, on day 14 of illness, whereas serology for confirmation may take 28 days to reach a detection rate above 90%. Recently, quantitative measurement of blood SARS CoV RNA with real-time RT-PCR technique has been developed with a detection rate of 80% as early as day 1 of hospital admission but the detection rates drop to 75% and 42% on day 7 and day 14, respectively.
Scale (NOS) for assessing the quality of nonrandomised studies in meta-analyses
- Newcastle-Ottawa
Newcastle-Ottawa Scale (NOS) for assessing the quality of nonrandomised studies in
meta-analyses.
2009
[cited
2020