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The Number Needed to Vaccinate to Prevent Infant Pertussis Hospitalization and Death Through Parent Cocoon Immunization
Abstract
Parental immunization has been recommended as a "cocoon" strategy to prevent serious pertussis outcomes in early infancy. We illustrate the high number needed to vaccinate (NNV) for this program based on recent epidemiologic data from the provinces of Québec and British Columbia (BC), Canada.
Surveillance trends were summarized for the period 1990-2010. Hospitalization, intensive care unit (ICU) admission, and mortality data were compiled from 2000 to 2009. The proportion of infant pertussis attributed to a parent was estimated at 35%, explored up to 55%. Adult vaccine efficacy (VE) was estimated at 85%. The NNV was calculated as [2 parents/(parent-attributable infant risk × parent VE)]. To capture at least 1 recent cyclical peak, NNV was derived for the period 2005-2009 and explored for peak/trough years.
Substantial decline has occurred in pertussis incidence across all age groups including infants, reaching a 20-year nadir in 2010 in both provinces. For the period 2005-2009, the risk of infant hospitalization and ICU admission was 57 and 7, respectively, per 100 000 in Québec and 33 and 7, respectively, per 100 000 in BC. In both provinces the risk of infant pertussis-related death over that period was <0.5 per 100 000. The NNV for parental immunization was at least 1 million to prevent 1 infant death, approximately 100 000 for ICU admission, and >10 000 for hospitalization.
In the context of low pertussis incidence, the parental cocoon program is inefficient and resource intensive for the prevention of serious outcomes in early infancy. Regions contemplating the cocoon program should consider the NNV based on local epidemiology.
... Les nourrissons de moins de 1 an présentent le risque le plus élevé de maladies graves, y compris d'hospitalisation, d'admission en unité de soins intensifs (USI) et de décès, le risque le plus élevé étant observé chez les très jeunes nourrissons de moins de 3 mois. 2,3 Après l'introduction au Canada, en 1943, d'un programme d'immunisation systématique des enfants au moyen d'un vaccin anticoquelucheux à germes entiers, l'incidence de la coqueluche a diminué de plus de 90 %, passant d'une moyenne de 165 cas pour 100 000 habitants entre 1935 et 1939 à 10 cas ou moins pour 100 000 habitants vers la fin des années des 1980, puis à un niveau historiquement bas de 4 cas pour 100 000 habitants en 1988. [4][5][6] Toutefois, malgré la mise en place de programmes d'immunisation universels des enfants, l'incidence de la coqueluche a augmenté de façon spectaculaire au Canada au cours des années 1990 et au début des années 2000 et une tendance à l'augmentation des taux d'infection a été observée chez les enfants plus âgés 4 . ...
... 4,14 Après les importantes éclosions de coqueluche observées à la fin des années 1990 et au début des années 2000, pendant lesquelles l'incidence provinciale a atteint un sommet avec 20 à 40 cas pour 100 000 habitants dans l'ensemble de la C.-B., l'activité de la coqueluche a chuté à de faibles niveaux variant entre 1 et 6 cas pour 100 000 habitants entre 2005 et 2011. Toutefois, cette activité historiquement faible en C.-B. est survenue simultanément aux nombreux signalements d'une résurgence de l'activité de la coqueluche aux États-Unis 3,15 principalement dans l'État de la Californie, également situé sur la côte ouest, où l'incidence globale d'environ 25 cas pour 100 000 habitants observée en 2010 a été la plus élevée en plus de 50 ans. 16 En 2012 et 2013, la C.-B. a connu d'autres sommets cycliques d'activité de la coqueluche dans certaines régions de la province. ...
... Les hospitalisations ont été fondées sur les cas de coqueluche confirmés exclusivement dans le cadre de la surveillance accrue mise en place au cours de l'éclosion de 2012. Le taux d'hospitalisation de 18 cas pour 100 000 habitants est inférieur aux estimations fondées sur le diagnostic clinique extraites des registres administratifs de congés des hôpitaux au cours des sommets observés précédemment en C.-B. (qui variaient entre 50 et 70 cas pour 100 000 habitants) 3 . Ces données n'étaient pas facilement accessibles aux fins de l'analyse actuelle. ...
... Young age <60 days old has previously been established to be a risk factor for ICU admission [7][8][9][10]. In this report, we aim to compare the risk factors for severe pertussis requiring intensive care/ high dependency (HD) admission against controls admitted to general wards. ...
... The age group of 3 months is similar to other publications that show the highest hospitalization and ICU admissions occur in this young age group [7][8][9][10]. In the study by Kaczmarek et al. from 1997 to 2013, ICU admissions were most frequent in children <6 weeks (41.8%) and 6 weeks to 4 months (42.9%) [7]. ...
... The waning immunity may contribute to the cyclical pattern of pertussis seen over time. This cyclical pattern has been described in other countries [10,41]. While the US has seen peaks every 3-5 years, our peaks in 2007, 2011 and 2015 indicate a 4yearly cycle. ...
Introduction:
Pertussis causes the highest complication rates and deaths in the infant group. Our study explored risk factors for ICU/high dependency (HD) admissions and intubation/non-invasive ventilation (NIV).
Methods:
A retrospective review of pertussis admissions over 10 years from 2007 to 2016 was done at KK Women's and Children's Hospital, Singapore. To understand risk factors for severe pertussis infection, we compared cases requiring ICU/HD care with controls admitted to the general ward. Risk factors for intubation/NIV were also studied. Vaccine efficacy for protection against ICU/HD admission or intubation/NIV was also calculated.
Results:
There were 200 pertussis patients with a median age of 2.75 months. Sixty-one % were ≤3 months and 14.5% were <6 weeks old. Majority of patients (77%) had no prior pertussis vaccination. After removing 3 patients with missing vaccination records, 20 cases were compared with 177 controls. On univariate analysis, risk factors for ICU/HD admission comprised: Age ≤3 months, contact history, underlying co-morbidity, prematurity, absent DTaP vaccination, lymphocytosis, hyperleukocytosis (wbc ≥50×109/L), thrombocytosis (platelet ≥500×109/L), and pneumonia. Multivariate analysis revealed that age ≤3 months (OR 40, 95% CI 4.57-1111.11, p=.007), co-morbidity (OR 8.46 (95% CI 1.47-56.89, p=.019), pneumonia (OR 18.08, 95% CI 3.22-132.15, p=.002), white cell count (OR 1.07, 95% CI 1.01-1.14, p=.023) and cyanosis (OR 5.09, 95% CI 1.31-24.71, p=.026) were risk factors for ICU/HD admission. Prior DTaP vaccination had a vaccine effectiveness of 86.5% in preventing ICU/HD admission and 82.1% in preventing intubation/NIV.
Conclusions:
As the majority of pertussis patients were infants ≤3 months old who are at high risk for ICU/HD admission and intubation/NIV, prevention is key to reducing pertussis morbidity. Even though not statistically significant, DTaP vaccination had a role in preventing ICU/HD admission and intubation/NIV.
... The disease outcomes reported were influenza in eight studies [4][5][6][7][8][9][10][11], tuberculosis in four studies [12][13][14][15], as well as three studies each of herpes zoster (HZ) [16][17][18], human papilloma virus (HPV) [19][20][21], and pertussis [22][23][24]. Two studies each focused on Hepatitis A [25,26] and pneumococcal disease [4,27]. ...
... Outcomes for which NNVs were measured included being a case of a specific disease, death, hospitalization, outpatient visit, qualityadjusted life year (QALY), disability-adjusted life year (DALY), and life-years lost. One third of the included studies (n = 9) used data from observational studies, which were primarily cohort studies [8][9][10]12,17,23,27,28,30]. In addition, seven studies were cost-effectiveness and economic analyses [4,5,13,15,16,21,22], six studies were systematic reviews [6,7,11,14,26,29]; three were commentaries [18,20,25], and two studies utilized mathematical modelling [19,24]. ...
... Eleven studies (41%), including seven economic analyses [4,5,13,15,16,21,22], two observational studies [23,30] and two systematic reviews [14,26] interpreted NNV in the context of a cost-effectiveness analysis of vaccination programmes. ...
The number needed to vaccinate (NNV) is a measure that has been widely used in the scientific literature to draw conclusions about the usefulness and cost-effectiveness of various immunization programmes. The main objective of this review is to examine how and why the NNV has been used and reported in the published literature.
Electronic databases were searched and records were screened against the eligibility criteria by two independent authors. We included papers that reported and interpreted NNV.
We identified 27 studies, the designs including observational studies, economic analyses, systematic reviews, and commentaries. The NNV has been used in the literature to describe three main themes: potential benefits of vaccination programmes, cost-effectiveness, and economic analyses, and modelling studies to compare different vaccination strategies.
NNV has been used in a wide variety of ways in the literature, yet there are no defined thresholds for what is a favourable NNV. Furthermore, the generalizability of the NNV is usually limited. Further work is required to determine the most appropriate use of this measure.
Copyright © 2014. Published by Elsevier Ltd.
... The entity is endemic in many places and it can cause the death of newborns. 3,8,40,41 According to Chilean studies, 16 infants under six months of age died in 2011; 13 of 1,240 notifications with a fatality rate of 1.04% in 2012; three newborns died in 2013 and seven in 2014. 16 In United Kingdom were reported sixteen deaths by pertussis in infants under three months old that were born before the introduction of MV. 513 hospitalizations were registered in children of the same age and in the same period of time, which allowed to estimate a rate of fatal cases of 3,1% [95%IC: 1,7-4,7]. ...
... 22 About this, Skowronski showed that in the period between 2005 and 2009 in Canada, the NNV was over 10.000 to prevent one hospitalization and one million to prevent death of infants younger than one year. 41 As the incidence becomes lower, the needed resources to achieve a further reduction are greater. In the study conducted in Italy, where it was also determined that the NNV to prevent hospitalization in younger children of one year was 10.000, the cost per case avoided was high: greater than EUR 100.000. ...
Pertussis, also called whooping cough, is an infectious and preventable pathology that generates important child morbidity and mortality worldwide. There are different biological preparations for its use in infants, while for adolescents and adults is Tdap, (acellular vaccine of purified extracts of Bordetella pertussis (BP), combined with tetanus and diphtheria toxoid) that has been proposed as maternal vaccination (MV). The objective was to identify the benefits of MV in the prevention of childhood pertussis, a review was made in PubMed, Science Direct, EBSCOhosT, OvidSP and Embase databases (years 2008-2016) and an electronic alert system (January-April 2017). 1083 titles were identified and 44 articles were selected. After the MV (administered between 27 and 36 weeks of gestation) the passage of IgG-BP to the fetus is sufficient to generate adequate infant protection, generating two benefits: reducing infant morbidity (number of cases and hospital admissions) and decreasing mortality by pertussis. The MV offers 93% of effectiveness [95%CI: 81-97] and OR: 0.09 [95%CI: 0,03-0,25]. The MV is more favorable in each pregnancy than cocoon strategy, vaccination before pregnancy, before 26 weeks of gestation or in the postpartum. The use of MV is a safe and cost-effectiveness tool to prevent childhood pertussis.
... Several studies (from Canada, Italy, and the United States) have estimated effectiveness by calculating the number needed to vaccinate to prevent pertussis outcomes. [44][45][46] Three of the analyses suggested that under the conditions of low pertussis incidence, the cocoon strategy is not efficient and would be very resourceintensive owing to the large numbers of individuals who would need to be vaccinated to prevent disease-related outcomes. [44][45][46] In contrast, a fourth study that compared various vaccination strategies found that the cocooning of parents of newborns paired with an adult booster would maintain a low level of pertussis incidence while being the most costeffective approach over a wide range of scenarios. ...
... [44][45][46] Three of the analyses suggested that under the conditions of low pertussis incidence, the cocoon strategy is not efficient and would be very resourceintensive owing to the large numbers of individuals who would need to be vaccinated to prevent disease-related outcomes. [44][45][46] In contrast, a fourth study that compared various vaccination strategies found that the cocooning of parents of newborns paired with an adult booster would maintain a low level of pertussis incidence while being the most costeffective approach over a wide range of scenarios. 47 These strategies included combinations of the infant primary series, adolescent booster, cocooning, and adult booster. ...
The Global Pertussis Initiative (GPI) is an expert scientific forum addressing the worldwide burden of pertussis, which remains a serious health issue, especially in infants. This age cohort is at risk for developing pertussis by transmission from those in close proximity. Risk is increased in infants aged 0 to 6 weeks, as they are too young to be vaccinated. Older infants are at risk when their vaccination schedules are incomplete. Infants also bear the greatest disease burden owing to their high risk for pertussis-related complications and death; therefore, protecting them is a high priority. Two vaccine strategies have been proposed to protect infants. The first involves vaccinating pregnant women, which directly protects through the passive transfer of pertussis antibodies. The second strategy, cocooning, involves vaccinating parents, caregivers, and other close contacts, which indirectly protects infants from transmission by preventing disease in those in close proximity. The goal of this review was to present and discuss evidence on these 2 strategies. Based on available data, the GPI recommends vaccination during pregnancy as the primary strategy, given its efficacy, safety, and logistic advantages over a cocoon approach. If vaccination during pregnancy is not feasible, then all individuals having close contact with infants <6 months old should be immunized consistent with local health authority guidelines. These efforts are anticipated to minimize pertussis transmission to vulnerable infants, although real-world effectiveness data are limited. Countries should educate lay and medical communities on pertussis and introduce robust surveillance practices while implementing these protective strategies.
Copyright © 2015 by the American Academy of Pediatrics.
... Moreover, the number needed to vaccinate (NNV) is very high to achieve effective cocooning. According to a study evaluating all pertussis reports (confirmed and clinical/probable) in Québec and British Columbia from Canada between 1990 and 2010, the NNV for parental immunization was calculated as not less than 1 million to prevent one infant death, approximately 100,000 to prevent intensive care admission, and at least 10,000 to prevent hospitalization [94]. ...
Pertussis, caused by Bordetella pertussis, remains one of the most widespread, contagious, and vaccine-preventable diseases. It results in notable morbidity and mortality as well as severe medical, social, and economic burden. Despite high global vaccine coverage, pertussis continues to be a significant epidemiologic problem, with outbreak episodes every few years just as in the pre-vaccination era. In Türkiye, there is a lack of comprehensive data on the current burden of pertussis in different age and risk groups, leading to underdiagnosis and underreporting of the disease, especially in adults who are often not considered at risk. Available data from Türkiye also reveal inadequate levels of protective antibodies in preterm newborns, emphasizing the need for additional preventive measures. Authors stated that improving physician awareness of pertussis symptoms in patients with prolonged cough, increasing access to routine pertussis tests, and conducting surveillance studies would aid in accurate diagnosis and reporting in Türkiye. As the Turkish Ministry of Health Antenatal Care Management Guide suggests routine second and third pregnancy check-up visits at weeks 18–24 and 28–32 correspondingly, this period can be considered the ideal vaccination time for Türkiye. Introducing a booster dose of Tdap at around 10 years of age or during national military service would reduce transmission and protect susceptible individuals. Identifying individuals at high risk of severe pertussis and prioritizing them for a booster dose is also crucial in Türkiye. Enhancing surveillance systems, increasing healthcare professionals’ awareness through training, and organizing catch-up visits for missed vaccinations during the COVID-19 pandemic are mentioned as additional strategies to improve pertussis prevention in Türkiye. This review focuses on the global and regional burden of pertussis and obstacles to effective prevention and evaluates existing strategies to achieve lifelong pertussis prevention. Literature and current strategies were also discussed from a Turkish national standpoint.
... Hospitalization rates were over eight times higher in infants under four months of age than infants between four and 11 months, which coincides with the first dose of the pertussis vaccine administered at two months of age. Three different studies, including a Canada-wide study by Desai et al. (25), a study covering British Columbia and Québec by Skowronski et al. (26) and a study in the United States by Masseria et al. (27), all reported similar findings showing pertussis hospitalizations were highest in infants under three months of age. The lower hospitalization rates among infants between four and 11 months of age, compared to infants under four months of age, can be attributed to less severe disease in older infants and to vaccinations. ...
Background:
Pertussis, also known as whooping cough, is an endemic vaccine-preventable disease that affects the respiratory tract and is caused by the bacterium Bordetella pertussis. Between 1999 and 2004, the adolescent booster dose of pertussis was introduced across Canada. This report describes the epidemiology of pertussis in Canada from 2005 to 2019, the period after adolescent acellular vaccination was recommended.
Methods:
We analyzed pertussis incidence by year, age groups, sex and geographic region using national surveillance data from the Canadian Notifiable Disease Surveillance System. Hospitalization data from the Discharge Abstract Database was used to investigate pertussis hospitalizations by sex and age. Deaths from pertussis were explored using Statistics Canada's vital statistics data. Vaccination coverage data was gathered from the 2019 Childhood National Immunization Coverage Survey and 2018-2019 Seasonal Influenza Vaccination Coverage Survey.
Results:
Between 2005 and 2019, there were a total of 33,481 pertussis cases with the average annual incidence rate of 6.4 cases per 100,000 population. The highest average age-specific incidence rate was among infants under one year of age (n=68.7 cases per 100,000 population). There were a total of 1,593 pertussis hospitalizations; nearly 80% of these hospitalizations were infants under one year of age. Hospitalization rates were 8.2 times higher in infants three months or younger compared to infants four to 11 months of age. There were 17 deaths; all among infants under one year of age.
Conclusion:
The highest morbidity and fatality of pertussis were among infants under one year of age. It is important to take measures to reduce transmission to infants who are too young to be vaccinated. Increasing vaccine coverage in children and pregnant women are important to reduce the burden of disease.
... Les taux d'hospitalisation étaient plus de huit fois plus élevés chez les nourrissons de moins de quatre mois que chez les nourrissons de 4 à 11 mois, ce qui coïncide avec la première dose du vaccin contre la coqueluche administré à deux mois. Trois études différentes, dont une étude pancanadienne de Desai et al. (25), une étude portant sur la Colombie-Britannique et le Québec de Skowronski et al. (26) et une étude réalisée aux États-Unis par Masseria et al. (27), ont toutes déclaré des résultats semblables, qui ont montré que les hospitalisations liées à la coqueluche étaient les plus élevées chez les nourrissons de moins de trois mois. Les taux d'hospitalisation plus faibles chez les nourrissons de 4 à 11 mois, par rapport aux nourrissons de moins de quatre mois, peuvent être attribués à des maladies moins graves chez les nourrissons plus âgés et à la vaccination. ...
... [1] This phenomenon is even seen in industrialized countries. [11,12] immunoglobulin G (IgG) antibody against pertussis in Iranian children have been evaluated in several studies, and different results were reported. [10,13,14] Without epidemiological studies in the various geographic regions and between different age groups, it is challenging to evaluate immunization programs (such as replacing the wP with aP, adding or elimination of booster doses, and special vaccination groups) and detection of high-risk populations. ...
Background:
Pertussis is a vaccine-preventable respiratory infection and seroepidemiology of the infection could be a marker of the pertussis immunity in a population. In many countries, despite vaccination coverage, high prevalence of pertussis has been observed. The present study aimed to evaluate the immunoglobulin G (IgG) antibody against pertussis and the role of demographic and anthropometric variables on the immunity rate in the Iranian pediatric population to evaluate the impact of existing immunization program in order to envisage future vaccination strategies to prevent infection.
Methods:
In a cross-sectional multi-centric study, 1593 samples of the students aged 7-18 years, who had been enrolled in a national survey (Childhood and Adolescence Surveillance and Prevention of Adult Noncommunicable disease-V), were randomly selected and tested for IgG antibody against Bordetella pertussis (BP) by enzyme-linked immunosorbent assay. The age, gender, education, residency, geographical region, and body mass index (BMI) were extracted from the questionnaires of the COSPIAN-Survey. Multiple logistic regression models were used to assess the associations between the variables with the IgG antibody against BP. Data were presented by odds ratio (OR), 95% confidence interval (95% CI) and P values (P): (OR [95% CI]; P).
Results:
Subjects were consisted of 774 boys and 750 girls, with a mean (standard deviation) age of 12.39 (3.03) years. Overall, BP seroprevalence was 59.8%. There were higher BMI values in seronegative ones versus seropositive (18.62 ± 4.07 vs. 18.15 ± 3.94, P = 0.041, 95% CI = 0.23 [0.02-0.92]). However, the categorized BMI for age was not significantly associated with IgG levels (0.27 [0.25-0.29]; 0.27). BP seroprevalence was not significantly different between geographical regions (0.06 [0.05-0.07]; 0.06), genders (1.17 [0.93-1.47]; 0.18), area of residence (1.07 [0.82-1.4]; 0.61), and educational levels (0.94 [0.75-1.19]; 0.62).
Conclusion:
IgG antibody against pertussis was not detected in nearly 40% of the subjects who had history of vaccination against pertussis. It is recommended to monitor the incidence of pertussis in high-risk populations closely and administer a booster dose of acellular pertussis vaccine in adolescents.
... Pertussis resurgence has been observed in recent years, and severe pertussis and death due to pertussis have gradually increased. According to other research, age ≤ 3 months is a risk factor for severe and death in pertussis cases [4][5][6][7][8][9], and 78.8% (63/89) of severe pertussis patients were aged ≤3 months in our hospital; this result is consistent with other studies. Our findings were consistent in 59 patients with severe pertussis who had a cough onset age of < 3 months after excluding 4 patients for whom treatment was terminated and who later died. ...
Background and purpose
Pertussis is a serious infectious disease in young infants, and severe cases frequently cause death. Our study explored risk factors for death from severe pertussis.
Method
A case-control study of infants with severe pertussis admitted to the paediatric intensive care unit (PICU) in the Children’s Hospital of Chongqing Medical University, China, from January 1, 2013, to June 30, 2019, was conducted. Pertussis was confirmed by clinical features and laboratory examinations. Severe pertussis was defined as patients with pertussis resulting in PICU admission or death. To understand the risk factors for death, we compared fatal and nonfatal cases of severe pertussis in infants aged < 120 days by collecting clinical and laboratory data.
Results
The participants included 63 infants < 120 days of age with severe pertussis. Fifteen fatal cases were confirmed and compared with 44 nonfatal severe pertussis cases, Four patients with termination of treatment were excluded. In the univariate analysis, the risk factors associated with death included apnoea (P = 0.001), leukocytosis (white blood cell (WBC) count≥30 × 10⁹/L (P = 0.001) or ≥ 50 × 10⁹/L (P = 0)), highest lymphocyte count (P = 0), pulmonary hypertension (P = 0.001), and length of PICU stay (P = 0.003). The multivariate analysis revealed that apnoea (OR 23.722, 95%CI 2.796–201.26, P = 0.004), leukocytosis (OR 63.708, 95%CI 3.574–1135.674, P = 0.005) and pulmonary hypertension (OR 26.109, 95%CI 1.800–378.809, P = 0.017) were significantly associated with death.
Conclusion
Leukocytosis and pulmonary hypertension exhibited the greatest associations with death in infants with severe pertussis admitted to the PICU. Vaccination is still the most effective protection method against pertussis.
... Consequently, attempts to protect young infants have advocated cocooning, which involves vaccinating household members, as well as antenatal and postnatal vaccination of mothers of neonates. Whereas cocooning does not seem cost-effective, antenatal vaccination of mothers has shown promising protection for infants with no added risk to either the mother or the pregnancy [36][37][38][39][40]. In our study, the risk of pertussis may be partially explained by the high proportion of HIV infected caregivers who exhibited a higher risk for nasopharyngeal carriage compared to HIV uninfected caregivers (5.4% vs 2.6%) although these findings were not statistically significant, most likely due to small numbers. ...
Introduction
Despite a resurgence of disease, risk factors for pertussis in children in low and middle-income countries are poorly understood. This study aimed to investigate risk factors for pertussis disease in African children hospitalized with severe LRTI.
Methods
A prospective study of children hospitalized with severe LRTI in Cape Town, South Africa was conducted over a one-year period. Nasopharyngeal and induced sputum samples from child and nasopharyngeal sample from caregiver were tested for Bordetella pertussis using PCR (IS481+/hIS1001). History and clinical details were documented.
Results
460 children with a median age of 8 (IQR 4–18) months were enrolled. B. pertussis infection was confirmed in 32 (7.0%). The adjusted risk of confirmed pertussis was significantly increased if infants were younger than two months [aRR 2.37 (95% CI 1.03–5.42]), HIV exposed but uninfected (aRR 3.53 [95% CI 1.04–12.01]) or HIV infected (aRR 4.35 [95% CI 1.24–15.29]). Mild (aRR 2.27 [95% CI 1.01–5.09]) or moderate (aRR 2.70 [95% CI 1.13–6.45]) under-nutrition in the children were also associated with higher risk. The highest adjusted risk occurred in children whose caregivers had B. pertussis detected from nasopharyngeal swabs (aRR 13.82 [95% CI 7.76–24.62]). Completion of the primary vaccine schedule (three or more doses) was protective (aRR 0.28 [95% CI 0.10–0.75]).
Conclusions
HIV exposure or infection, undernutrition as well as detection of maternal nasal B. pertussis were associated with increased risk of pertussis in African children, especially in young infants. Completed primary vaccination was protective. There is an urgent need to improve primary pertussis vaccine coverage in low and middle-income countries. Pertussis vaccination of pregnant women, especially those with HIV infection should be prioritized.
... Il a montré une chute drastique de ces verrues, y compris dans la population non vaccinée (effet collectif) [17]. [29]. Pour la vaccination grippale chez l'enfant le NNV est de 1000 à 7000 suivant l'âge pour éviter une hospitalisation. . . ...
Papillomavirus (HPV), the first sexually transmitted disease in the world, is the main infectious agent responsible for cancer (6300 per year, in France). The cycle of HPV infection - >precancerous lesions - >cancer is well documented with regard to the cervix (cf. Nobel Prize in 2008). While this area is the most frequent (3000), it is far from being the only one. Other cancers include the anus, oropharyngeal sphere, glans and vulva. The sum of these other induced HPV cancers is greater than the total number of cervical cancers and also concerns boys. Screening is essential but insufficient and only concerns the cervix. Only vaccination can provide primary and general prevention. Since 2007, there have been many studies demonstrating its excellent efficacy and tolerance. However, France lags behind other countries with a vaccination coverage (<30 %) that does not allow for an epidemiological impact.
Copyright © 2020 Société Française du Cancer. Published by Elsevier Masson SAS. All rights reserved.
... One reason for using infants as a comparison group was because they were consistently aP-primed across all IRR analysis periods and were not impacted by this moving cohort effect. Finally, we did not consider indirect impact of adolescent pertussis vaccination on other age groups but this is anticipated to be small since Tdap has limited capacity to prevent B. pertussis colonization, adolescents have few contacts with infants, and cocooning programs have been shown inefficient even in those with such contacts [17,19,20]. ...
Impact of an adolescent tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccine program was assessed in the provinces of British Columbia and Quebec, Canada. In both provinces, the Tdap booster has been in place since 2004, targeting Grade 9 students (14-15-years-of-age). Incidence rate ratios (IRRs) standardizing notification rates among teens 15-19-years-old to infants <1-year-old decreased following introduction of the Tdap program and were significantly halved during the 2009-2012 post-Tdap versus 2000-2003 pre-Tdap period. This program impact, however, is tempered by the observation that pertussis incidence among 15-19-year-olds was already lower than any other pediatric age group, following gradual decline from pre-teen rates even before the Tdap program. The risk of hospitalization among adolescents 15-19-years-old was also low throughout at <1/100,000. Furthermore, IRRs increased in 2013-2017 when an increasing proportion of 15-19-year-olds were primed with acellular pertussis vaccine only, suggesting short-lived Tdap booster-dose effectiveness that warrants further monitoring.
... However, widening coverage with pertussis vaccines appears to have had little impact in preventing transmission to young infants or on the resurgence of periodic epidemic peaks in some countries in recent years [11,13,17]. Concerns that close contacts continue to remain common reservoirs for disease transmission to young infants have led to vaccination against pertussis during pregnancy [18][19][20][21][22][23]. Vaccination during pregnancy protects the mother directly, and, more importantly, provides passive protection (via transplacental antibody transfer in utero) for their young infants. ...
Infants are vulnerable to pertussis infection particularly before initiation of pertussis vaccination. Maternal pertussis vaccination during pregnancy has been introduced in a number of countries in order to confer on young infants indirect protection from the disease through transplacental transfer of maternal antibodies. We reviewed the evidence on the immunogenicity and efficacy of maternal pertussis vaccination during pregnancy. A systematic search of PubMed/MEDLINE, EMBASE, Scopus, Cochrane Database of Systematic Reviews, ProQuest, and Science Direct was undertaken to identify studies published between January 1995 and December 2018. This review was not specific to any particular pertussis vaccine but included applicable data on available pertussis vaccines administered to pregnant women. The search identified 40 publications for inclusion in this review. Vaccination during pregnancy elicited robust maternal immune responses against all vaccine antigens and resulted in high placental transfer of pertussis antibodies to the infant that persisted well beyond delivery. Vaccination during the second or early third trimesters was considered ideal for antibody quantity and functionality. Although blunting of immune responses to some antigens in the primary immunization series was documented in neonates born to women vaccinated during pregnancy, there was no apparent adverse effect on vaccine efficacy. Multiple studies conducted in diverse settings have confirmed the effectiveness of maternal pertussis vaccination during pregnancy in preventing pertussis in infants prior to receipt of their first primary vaccine dose and beyond. These findings collectively underscore the value of maternal pertussis vaccination during pregnancy in protecting vulnerable infants too young to be vaccinated.
... However, only 23% of pregnant women in a large nationwide cross-sectional survey in 2013 [11] and 22% of household contacts of infants interviewed as part of a large population based telephone survey in 2012/13 reported having obtained a pertussis vaccination within the last 10 years, the latter an increase of 11% from 2009/2010 [26,27]. In addition, several studies have shown limited impact of cocooning strategies on infant pertussis disease burden [28][29][30][31][32]. ...
Background:
In Germany, antenatal influenza vaccination is recommended since 2010, but uptake remains low. Several countries recently introduced antenatal pertussis vaccination, which is currently under consideration in Germany. We conducted a survey among gynaecologists on attitudes, practices and barriers regarding influenza and pertussis vaccination during pregnancy.
Methods:
Gynaecologists were invited to complete a pre-tested, 24-item questionnaire published in the German Professional Association of Gynaecologists' journal in September 2017 within 2 months. Associations between variables were examined using Chi-Squared, Fischer's Exact or t-tests. Variables associated with gynaecologists' self-reported implementation of vaccination in pregnant women were identified using univariate and multivariate logistic regression analyses.
Results:
Of 867 participants (response 11%), 91.4 and 59.4% reported currently vaccinating pregnant women against influenza and pertussis, respectively. Gynaecologists who reported obtaining annual influenza vaccination and actively informing their patients about these vaccinations were significantly more likely to vaccinate pregnant women against influenza (96.5% vs. 65.7 and 95.1% vs. 62.2%) and pertussis (63.1% vs. 44.3 and 82.4% vs. 12.9%). Performing influenza vaccination was least likely among gynaecologists who perceived logistical difficulties as a vaccination barrier (35.9%), while pertussis vaccination was least likely if the lacking official recommendation (32.0%), logistical difficulties (27.1%), safety concerns (17.5%) and limited vaccine effectiveness (11.1%) were perceived as barriers. Of participants not yet vaccinating pregnant women against pertussis, 86.5% reported they would follow an official recommendation. Including vaccination recommendations in the maternity record (95.2%) and informing the public (88.7%) and health care professionals (86.6%) were considered the most suitable measures to achieve high pertussis vaccination coverage.
Conclusions:
The large proportion reporting performance of influenza vaccination during pregnancy and high acceptance of a potential recommendation for pertussis vaccination reflected positive attitudes towards vaccination among participants. However, factors associated with failure to vaccinate may be more prevalent among non-participants. Results suggest that gynaecologists' confidence in vaccination is crucial for implementing vaccination in pregnancy. Thus, doubts on vaccine effectiveness and safety should be allayed among gynaecologists and pregnant women via various communication channels, and solutions for logistical barriers sought. Including antenatal vaccination recommendations in the maternity record would serve as an important reminder for both groups.
... In Canada, it would be necessary to vaccinate more than 10,000 people to prevent one hospitalization, and vaccinate at least 1 million to prevent one death of infant <1 year of age, in a setting with 57 hospitalizations per 100,000 inhabitants and risk of parentsto-infant transmission of 35%. 52 In the USA, a study of a postpartum vaccination program did not show any beneficial effect. 53 After a frustrating performance of the previous strategies, pregnant women vaccination was introduced in USA, in 2011, and UK, in 2012. ...
During the last decades pertussis incidence raised globally. Several vaccination strategies targeting adults to reduce pertussis among young infants have been proposed, including vaccination of healthcare workers (HCWs). The aim of this study was to analyse, by performing a systematic review of literature, published papers that evaluated Tdap coverage among HCWs, variables associated with vaccine uptake and efforts implemented to raise vaccination rates. We searched the MedLine, Embase, SCOPUS, LILACS, Web of Science and Cochrane for full-text studies that evaluated Tdap coverage in HCW. Two independent reviewers screened the articles and extracted the data. Twenty-eight studies published from 2009 to 2018 were reviewed. Most studies were conducted in the USA. Initial Tdap coverage varied from 6.1% to 63.9%. USA and France are the only two countries with studies evaluating Tdap coverage within HCWs using national data. In the USA, Tdap coverage in HCWs raised from 6.1% to 45.1% from 2007 to 2015. In the analysis of French national data, a Tdap coverage of 63.9% was observed. Five studies used interventions to raise Tdap coverage in HCWs. Two intervention studies implemented mandatory vaccination and three used educational strategies. All of them achieved coverages over 86%. Only eleven studies analysed the association of Tdap vaccination with variables of interest. Previous immunization with other vaccines recommended for HCWs (like influenza, hepatitis B and MMR) was positively associated with Tdap uptake in four studies. In conclusion, overall Tdap coverage among HCWs is low, but seems to increase over the years after the vaccine introduction and with implementation of interventions to increase coverage.
... In Canada, it would be necessary to vaccinate more than 10,000 people to prevent one hospitalization, and vaccinate at least 1 million to prevent one death of infant <1 year of age, in a setting with 57 hospitalizations per 100,000 inhabitants and risk of parentsto-infant transmission of 35%. 52 In the USA, a study of a postpartum vaccination program did not show any beneficial effect. 53 After a frustrating performance of the previous strategies, pregnant women vaccination was introduced in USA, in 2011, and UK, in 2012. ...
The reemergence of pertussis in the last two decades led to the introduction of adolescents and adults immunization strategies of tetanus–diphtheria–acellular pertussis vaccines (Tdap) in several countries. The health authorities must consider economic aspects when deciding to recommend and fund new programs. Here we present a systematic review of worldwide full economic evaluations of pertussis vaccination targeting adolescents or adults published from 2000. Studies were identified by searching MEDLINE, Excerpta Medica, CRD, and Lilacs databases. Twenty-seven economic evaluations of different strategies with Tdap were identified. Booster vaccination for adolescents and adults were the most frequent, followed by cocooning and pregnant women vaccination. Strategies performance varied considerably among different studies. Assumptions regarding underreporting correction, herd protection and vaccine coverage were crucial to cost-effectiveness results. Understanding the model and the parameters used is essential to understand the results, and identify the major issues important to public health decisions.
... For all countries, including those in Africa currently using the wP vaccine for primary immunization, the WHO recommends continuing the same approach to increase primary vaccination coverage [35]. Vaccination of pregnant women with the aP vaccine is likely to be a more cost-effective measure in preventing pertussis in infants too young to be vaccinated compared with the cocooning strategy that involves a much higher number of vaccine doses [35,39], but the higher cost of aP vaccines compromises maternal immunization strategies in most African countries. ...
Pertussis remains a major cause of morbidity and mortality, particularly in infants and young children, and despite the availability of vaccines and pertinent national and international guidelines. The disease burden is more severe in low- and middle-income countries (LMICs), especially in the African continent. Pertussis is more prevalent among young infants in Africa. Poor or no pertussis surveillance, lack of disease awareness, diagnostic limitations, and competing health priorities are considered key contributory factors for this high pertussis burden in Africa. Most African countries use whole-cell pertussis (wP) vaccines, but coverage with three primary doses of diphtheria-tetanus-pertussis vaccines falls short of the World Health Organization's recommended goal of >90%. The Global Pertussis Initiative (GPI) works toward developing recommendations through systematic evaluation and prioritization of strategies to prevent pertussis-related infant and child deaths, as well as reducing global disease burden to acceptable national, regional, and local levels. For countries using wP vaccines, the GPI recommends continuing to use wP to improve primary and toddler booster vaccination coverage. Vaccination during pregnancy is the next priority when acellular pertussis (aP) vaccines and other resources are available that directly protect newborns too young to be vaccinated, followed by, in order of priority, booster doses in older children, adolescents, healthcare workers and finally, all adults. Improved surveillance should be a high priority for African LMICs assessing true disease burden and vaccine effectiveness to inform policy. More research is warranted to evaluate the safety and efficacy of wP and aP vaccines and strategies, and to determine their optimal use.
... Initial computer simulation studies have suggested that a cocoon strategy including all household contacts would result in a 70% reduction in incidence of pertussis in infants up to 3 months of age (Van Rie and Hethcoe HW, 2004). However, more recent calculations show that the number needed to vaccinate in order to prevent severe infant pertussis through cocoon immunization would be such that in the context of a low pertussis incidence this strategy would be too resource intensive and rather inefficient (Skowronski et al., 2012). By combining the data from natural infection with a contact network structure, a mathematical model indicated that regular boosters up to once every five years starting at age 11 would reduce the global pertussis burden by only approximately 15 %, even with a logistically unfeasible vaccination coverage of 75% . ...
Pertussis or whooping cough is a severe and highly contagious respiratory tract disease that can be fatal, especially during the first months of life. The main etiological agent of this disease is the Gram-negative bacterium Bordetella pertussis. This chapter first presents the clinical manifestations of the disease. This is followed by discussions on the Bordetella virulence, and the re-emergence of pertussis. Next, the vaccines for the disease and their shortcomings are detailed. As a potential solution to the problem of the increasing pertussis incidence in young teenagers in the absence of a more effective and durable pertussis vaccine, repeated administrations of booster doses have been proposed. A slight acceleration of pertussis vaccination for infants by advancing the first dose from 8 to 6 weeks of age reduced the average severe disease notification rates by roughly 10% in Australia.
... However, while the strategy works moderately well in research studies and some clinical settings, the programs are costly and have proven difficult to implement on a large scale.(8) Furthermore, they are not cost effective in preventing pertussis deaths in infants <6 months of age, (9) and are, therefore, unlikely to be cost effective in preventing influenza deaths in same age group. ...
Influenza is a serious problem for infants <6 months of age, whose hospitalization rates for influenza and associated illness are comparable with rates in the elderly. Because influenza vaccines are not effective in this age group, the optimal evidence-based strategy is to administer trivalent inactivated influenza vaccines during pregnancy. Immunizing with trivalent inactivated influenza vaccines in the second and third trimester is well studied and safe, not only providing protection for the pregnant woman and her infant <6 months of age, but also for the fetus by decreasing the risk for low birth weight.
... 9 In the face of this global epidemiological panorama, several strategies have been implemented, including administering a 6th dose of the tetanus, diphtheria, and pertussis acellular (Tdap) vaccine in adolescence 10 and immunizing adolescents and adults that live with newborns, 11 although this latter strategy is considered impractical and costly. 12,13 Administering Tdap to pregnant women with the aim of intensifying the transfer of antibodies to the child 14,15 seems appropriate ; however, there are reservations about its safety. 16 In the United States, the Vaccine Adverse Event Reporting System stated that no adverse events occurred in 42% (55) of individuals who received Tdap immunization. ...
Immunization with the tetanus, diphtheria, and pertussis (Tdap) vaccine raises controversies on immunogenicity and possible antibody interference. We performed an experimental, double-blind, parallel group controlled clinical trial to evaluate the safety and immunogenicity of the Tdap vaccine in 204 pregnant women and their children and to determine its interference in antibody production. Pregnant women 18 to 38 years of age with 12 to 24 weeks gestation, a low obstetric risk, and without serious disease were randomly selected. The experimental group received 0.5 mL IM of Tdap and the control group normal saline. Six blood samples were drawn before and after solution application, and from the umbilical cord of the infants and at 2, 4, and 6 months of age. Pertactin and Pertussis toxin antibodies and possible interference of maternal antibodies with the vaccine were determined.
In the experimental group, antibodies against Bordetella pertussis pertactin (anti-PRN) (112 E/mL 95% CI 89.9 – 139.9) and antibodies against pertussis toxin (anti-PT) (24.0 E/mL, 95% CI 18.3 – 31.4) were elevated in the mother before vaccination. These were higher in the umbilical cord and descended in the infant at 2 months (71.4 (95% CI 56.8 – 89.7 and 10.9; 95% CI 8.7 –. 13.7, respectively). Anti-PT showed a delay in production. Tdap safety was confirmed with only mild local pain at 24 and 48 hours.
Anti-PRN and anti-PT antibodies in the infant descend at two months of age. There is a delay in anti-PT in children of immunized mothers. Further studies are needed to elucidate its clinical significance.
... 31 Moderate uptake rates were also reported in select programs in Europe. 32,33 However, a study in Canada noted poor cost -effectiveness for cocooning when pertussis incidence was low, 34 and outcome studies performed in the US and Australia demonstrated little or modest clinical effectiveness of cocooning. [35][36][37] These studies demonstrate the inherent limitations of cocooning as a stand-alone pertussis prevention strategy for infants, although it remains a recommended component of a multi-faceted approach to decrease pertussis disease burden. ...
Pertussis has had a resurgence with the highest incidence and complication rates in young infants, and deaths occurring mainly at < age 3 months. Infants are infected by older individuals whose immunity has waned. Strategies such as targeted immunization of infant caregivers have had limited success. Pertussis vaccination in pregnancy may protect infants through passive and active transfer of maternal antibodies that protect the infant until the primary immunization series. Studies show vaccinating pregnant women with acellular pertussis vaccine is safe for mother and infant, immunogenic with efficient transfer of antibodies to infants, and effective in preventing pertussis in young infants. Vaccine uptake in pregnant women is sub-optimal, but provider recommendation is the most important factor in improving vaccination rates. Studies are ongoing to determine the best timing of vaccination to protect infants, and into other strategies. Vaccinating pregnant women offers hope to prevent pertussis-related morbidity and mortality in infants worldwide.
... In view of the Global Vaccine Action Plan, further efforts are required to reduce the preventable burden of pertussis. Although accelerated vaccination programs may reduce pertussis hospitalizations (26), further vaccination efforts could be directed toward increasing acellular pertussis immunization in pregnant women, combined with cocooning (27,28). Cocooning refers to protecting infants from infectious diseases by vaccinating those in close contact with them, including parents and siblings. ...
Objectives:
Despite World Health Organization endorsed immunization schedules, Bordetella pertussis continues to cause severe infections, predominantly in infants. There is a lack of data on the frequency and outcome of severe pertussis infections in infants requiring ICU admission. We aimed to describe admission rates, severity, mortality, and costs of pertussis infections in critically ill infants.
Design:
Binational observational multicenter study.
Setting:
Ten PICUs and 19 general ICUs in Australia and New Zealand contributing to the Australian and New Zealand Paediatric Intensive Care Registry.
Patients:
Infants below 1 year of age, requiring intensive care due to pertussis infection in Australia and New Zealand between 2002 and 2014.
Measurements and main results:
During the study period, 416 of 42,958 (1.0%) infants admitted to the ICU were diagnosed with pertussis. The estimated population-based ICU admission rate due to pertussis ranged from 2.1/100,000 infants to 18.6/100,000 infants. Admission rates were the highest among infants less than 60 days old (p < 0.0001). Two hundred six infants (49.5%) required mechanical ventilation, including 20 (4.8%) treated with high-frequency oscillatory ventilation, 16 (3.8%) with inhaled nitric oxide, and 7 (1.7%) with extracorporeal membrane oxygenation. Twenty of the 416 children (4.8%) died. The need for mechanical ventilation, high-frequency oscillatory ventilation, nitric oxide, and extracorporeal membrane oxygenation were significantly associated with mortality (p < 0.01). Direct severe pertussis-related hospitalization costs were in excess of USD$1,000,000 per year.
Conclusions:
Pertussis continues to cause significant morbidity and mortality in infants, in particular during the first months of life. Improved strategies are required to reduce the significant healthcare costs and disease burden of this vaccine-preventable disease.
... This strategy involves immunization of all household contacts (with DTwP/DTaP or Tdap as appropriate for age), including parents and other family members immediately after childbirth [153,163]. However, complete immunization of household members and other contacts whom the newborn may encounter poses substantial programmatic challenges to ensure widespread vaccine availability, as well as provider education and outreach to ensure timely Tdap immunization of fathers and postpartum women and routine DTaP immunization of age-eligible children [164,165]. Encouragingly, recent data reported in 2014 from the UK suggested that maternal Tdap immunization is 91 % effective in preventing pertussis among newborns \8 weeks of age [166]. ...
Pertussis is a potentially severe respiratory disease, which affects all age groups from young infants to older adults and is responsible for an estimated 195,000 deaths occurred globally in 2008. Active research is ongoing to better understand the pathogenesis, immunology, and diagnosis of pertussis. For diagnosis, molecular assays (e.g., polymerase chain reaction) for detection of Bordetella pertussis have become more widely available and support improved outbreak detection. In children, pertussis vaccines have been incorporated into routine immunization schedules and deployed for pertussis outbreak control. Lower levels of vaccine coverage are now being observed in communities where vaccine hesitancy is rising. Additionally, recognition that newborn babies are at risk of pertussis in the USA and UK has led to recommendations to immunize pregnant women. Among adolescents and older adults in the USA, Tetanus Toxoid, Reduced Diphtheria Toxoid and Acellular pertussis (Tdap) Vaccines are recommended, but substantial individual- and system-level barriers exist that will make achieving national Healthy People 2020 targets for immunization challenging. Current antimicrobial regimens for pertussis are focused on reducing the severity of disease, reducing rates of sequelae, and minimizing transmission of infection to susceptible individuals. Continued surveillance for pertussis will be important to identify opportunities for reducing young infants' exposure and reducing the impact of outbreaks among school-aged children. Laboratory-based surveillance for newly emerging strains of B. pertussis will be important to identify strains that may evade protection elicited by currently available vaccines. Efforts to develop new-generation pertussis vaccines should be considered now in anticipation of vaccine development programs, which may require ten or more years to deliver a licensed vaccine.
... The results of this study, along with the previously reported low rates of immunisation in adults between the ages of 20 and 39 [5], suggest that the current immunisation guidelines including the "cocooning" strategy are either inadequately applied in real life or are insufficient in and of themselves in preventing the spread of pertussis to infants, as also observed recently in Canada [23]. Indeed, although the "cocooning" immunisation strategy was implemented in 2004 and a booster immunisation was added for young adults in 2008, there is no evident impact on the number of infants requiring hospitalisation. ...
Inclusion and exclusion criteria
Patients having at least one hospital stay in mainland France with a diagnosis (PD, RD or AD) of pertussis were included in the study. Hospital stays in the overseas departments and territories of France were excluded. The following 4 ICD-10 codes [9] were used to extract patient stays: whooping cough due to Bordetella pertussis (A370), whooping cough due to Bordetella parapertussis (A371), whooping cough due to other Bordetella species (A378) and whooping cough, unspecified species (A379). Due to the long refractory period following a natural infection by pertussis [10], the initial stay and all subsequent related stays over the 7-year period were considered to be a single case of pertussis.
Analyses
The patient’s initial stay was used for determining the socio-demographic characteristics of the case. To avoid double counting, only the date of the initial stay was taken into account in calculating the number of cases and in the epidemiologic analyses. Both the initial stay and all subsequent stays related to pertussis were included in the clinical and economic analyses of patient stays. In order to perform a subanalysis of the most severe cases of pertussis, three criteria were defined: cases requiring mechanical ventilation, cases requiring treatment in an intensive care or critical care unit (ICU/CCU) and/or cases culminating in the death of the patient [11].
Patient characteristics and description of cases
For the 2006-2012 study period, 7,058 hospitalised patients with pertussis were identified, among them 44.9% were male. More than half the patients were less than 1 year old, with the highest proportion being less than 3 months old (Figure 1). Patients aged 50 years or older represented the second largest age group and children aged between 6 and 17 years the smallest. Part of patients were infected by Bordetella pertussis (37.3%) and Bordetella parapertussis (2.0%) whereas in most cases the species of Bordetella were not specified (58.0%) or other species (2.7%). Two prominent peaks in the number of cases are visible in 2009 and 2012 (Figure 2). The greatest number of initial stays for pertussis took place in 2012.
... Normally a diagnosis of pertussis is not made in this age group as they have less-severe disease than infants [26][27]. However, several studies in different countries have found that the age pattern of pertussis has changed and the incidence of cases in adolescents and adults has increased [28][29][30][31][32][33]. This may be because the vaccination coverage in older people is lower than in infants and also because of a loss of immunity [34]. ...
Pertussis causes a large number of cases and hospitalizations in Catalonia and Navarra. We made a study of household cases of pertussis during 2012 and 2013 in order to identify risk factors for hospitalization in pertussis cases. Each primary case reported triggered the study of their contacts. Close contacts at home and people who were in contact for >2 hours during the transmission period of cases were included. The adjusted OR and 95% confidence intervals (CI) was calculated using logistic regression. A total of 1124 pertussis cases were detected, of which 14.9% were hospitalized. Inspiratory whoop (aOR: 1.64; CI: 1.02-2.65), apnoea (aOR: 2.47; CI: 1.51-4.03) and cyanosis (aOR: 15.51; CI: 1.87-128.09) were more common in hospitalized than in outpatient cases. Hospitalization occurred in 8.7% of correctly-vaccinated cases, 41.1% of non-vaccinated cases and 9.4% of partially-vaccinated cases. In conclusion, inspiratory whoop, apnoea and cyanosis were associated factors to hospitalization while vaccination reduced hospitalizations due to pertussis.
... Several related articles including cost evaluations have also indicated that cocooning is not an efficient approach to reduce pertussis hospitalizations and deaths in this age group in settings where there is a low incidence of the infection. In the 2005 to 2009 period in Canada [25], the NNV was more than 10,000 to prevent one hospitalization and at least 1 million to prevent one death in infants <1 year, in a setting with an incidence of 57 hospitalizations per 100,000 inhabitants and a 35% risk of transmission from the infant's parents. For the 2005 to 2010 period in Italy [26], the NNV to prevent one hospitalization in children <1 year was almost 10,000, with an incidence of 54 hospitalizations per 100,000. ...
Pertussis, also known as whooping cough, is an acute respiratory disease. The most common causative agent is Bordetella pertussis, and less frequently, other types of Bordetella may cause similar clinical manifestations and course. The first pertussis epidemic was reported in France by Guillaume de Baillou, and the illness was popularly called “Quinta” or “Quintana.” Baillou provided the first detailed clinical description of a whooping cough epidemic that occurred in 1578 [1]. Although pertussis affects all age groups, it has a more severe course in children, especially in unvaccinated individuals and infants. Vaccination is the most effective way to prevent pertussis. After whole-cell vaccines were introduced in 1940, the number of pertussis cases decreased. The acellular pertussis vaccine is more commonly used today. Bordetella pertussis infection in infants should initially be prevented by vaccination during pregnancy and cocoon strategy. The data on hearing loss (HL) associated with B. pertussis are limited.
Objective
Reports of efficacy, effectiveness and harms of COVID-19 vaccines have not used key indicators from evidence-based medicine (EBM) that can inform policies about vaccine distribution. This study aims to clarify EBM indicators that consider baseline risks when assessing vaccines’ benefits versus harms: absolute risk reduction (ARR) and number needed to be vaccinated (NNV), versus absolute risk of the intervention (ARI) and number needed to harm (NNH).
Methods
We used a multimethod approach, including a scoping review of the literature; calculation of risk reductions and harms from data concerning five major vaccines; analysis of risk reductions in population subgroups with varying baseline risks; and comparisons with prior vaccines.
Findings
The scoping review showed few reports regarding ARR, NNV, ARI and NNH; comparisons of benefits versus harms using these EBM methods; or analyses of varying baseline risks. Calculated ARRs for symptomatic infection and hospitalisation were approximately 1% and 0.1%, respectively, as compared with relative risk reduction of 50%–95% and 58%–100%. NNV to prevent one symptomatic infection and one hospitalisation was in the range of 80–500 and 500–4000. Based on available data, ARI and NNH as measures of harm were difficult to calculate, and the balance between benefits and harms using EBM measures remained uncertain. The effectiveness of COVID-19 vaccines as measured by ARR and NNV was substantially higher in population subgroups with high versus low baseline risks.
Conclusions
Priorities for vaccine distribution should target subpopulations with higher baseline risks. Similar analyses using ARR/NNV and ARI/NNH would strengthen evaluations of vaccines’ benefits versus harms. An EBM perspective on vaccine distribution that emphasises baseline risks becomes especially important as the world’s population continues to face major barriers to vaccine access—sometimes termed ‘vaccine apartheid’.
Résumé
Plusieurs pays à niveau de santé périnatale élevée ont débuté une politique de vaccination des femmes enceintes contre la coqueluche. À ce jour, la France n’a pas choisi cette politique.
L’objectif est de faire le point des connaissances concernant la mortalité par coqueluche chez le nourrisson. Comparer les stratégies disponibles pour protéger le nourrisson avant sa première vaccination, prévue à l’âge de deux mois.
Nous avons procédé à une analyse de littérature, depuis janvier 1998 jusqu’à 2021. En recherchant les mots clés utilisés suivants ; « Coqueluche, vaccination, grossesse, stratégie, cocooning », sur les bases scientifiques « Pubmed », ainsi que les recommandations françaises et étrangères de vaccination.
Actuellement 90% des morts par coqueluche sont des nourrissons de moins de six mois et cette mortalité représente 2 % de la mortalité de la première année de vie. La vaccination à la naissance n’offre pas d’efficacité suffisante. La stratégie cocooning, qui consiste à vacciner l’entourage de l’enfant, est coûteuse et difficile à mettre en place. Une politique de vaccination systématique des femmes enceintes s’avère efficace et raisonnablement couteuse si on la compare à la stratégie cocooning. Elle s’est récemment accompagnée d’une réduction de 78% des cas confirmés de coqueluche des nourrissons de moins de six mois en Angleterre.
En conclusion, son efficacité et son coût sont en faveur de la vaccination anticoquelucheuse des femmes enceintes, et ce à chaque grossesse.
Pertussis (whooping cough) is a highly infectious disease caused by Bordetella pertussis. Mothers lacking adequate immunity and contracting the disease represent the biggest risk of transmission to new-borns, for which the disease is often a threat. The aim of the study was to estimate the frequency of pertussis susceptibility among pregnant women, in order to point out the need for a vaccine recall during pregnancy, and to evaluate the antibody response in already vaccinated women. A cross-sectional observational study was conducted in the blood test centre of “St. Anna” Obstetrics and Gynaecology Hospital in Turin (Piedmont, Italy). Eligibility criteria included pregnant women coming to the centre for any blood test, aged 18 or above and with gestational age between 33 and 37 weeks at the moment of the blood draw. The data collection was carried out from May 2019 to January 2020 and the concentration of anti-Pertussis Toxin (anti-PT) IgG was measured through the Enzyme-Linked Immunosorbent Assay (ELISA) technique. Two-hundred women (median age 35) were enrolled: 132 (66%) had received at least one dose of pertussis vaccine, 82 of which during pregnancy. Recently vaccinated women had significantly higher antibody titres (even 12–15 times as high) compared to those vaccinated more than 5 years before or never vaccinated at all (p < 0.0001). Moreover, 95.1% of recently vaccinated women had anti-PT IgG levels above 10 IU/ml, and 85.4% above 20 IU/ml, while the same proportions were as low as 37% and 21% (respectively) in the group of women not vaccinated in pregnancy. This study confirmed that the vaccination is greatly effective in ensuring high antibody titres in the first months after the booster vaccine, with considerable differences in anti-PT IgG compared to women vaccinated earlier or never vaccinated at all, and therefore vaccinating pregnant women against pertussis still represents a valuable strategy.
Résumé
La vaccination est l’action de santé publique la plus efficace qui a permis de faire disparaître ou de réduire très fortement l’incidence des maladies infectieuses. Elle est cependant menacée par l’hésitation vaccinale déclenchée et entretenue par des polémiques sur ses effets indésirables, pour la plupart non scientifiquement confirmés. Elle procure une protection individuelle mais aussi collective par immunité de groupe. Il existe deux types de vaccins : vivants atténués et inactivés préparés à partir de germes inactivés ou de fractions du pathogène identifiés comme responsables de la réaction immune. À l’antigène sont ajoutés des conservateurs, des résidus et des adjuvants qui renforcent la réponse immune et s’avèrent indispensables pour l’efficacité de la plupart des vaccins sous-unitaires. L’aluminium est l’adjuvant le plus utilisé et n’est pas remis en cause en l’absence de démonstration des effets adverses qui lui sont attribués par quelques-uns. Certains vaccins ne protègent que contre une maladie. Le développement des vaccins combinés permet de simplifier la vaccination des enfants en réduisant le nombre d’injections. Les vaccins peuvent entraîner des effets indésirables au point d’injection ou généraux (fièvre, malaise, etc.). La quasi-totalité des effets indésirables graves attribués aux vaccins n’a pas été confirmée par les études scientifiques. Les contre-indications sont rares : vaccins vivants chez les immunodéprimés et les femmes enceintes, allergie à un des composants du vaccin. Cet article décrit l’épidémiologie des maladies à prévention vaccinale, le calendrier vaccinal français en population générale et dans des situations particulières, notamment pour les prématurés, les femmes enceintes, les immunodéprimés et les voyageurs et fait le point sur l’évolution récente de la politique vaccinale en France.
Pertussis remains a serious global health issue in infants aged less than 6 months. Neonates and young infants have the highest risk of developing pertussis as they are too young to be vaccinated and thus are more likely to develop more severe pertussis-related complications, including death. Protecting this vulnerable age population from pertussis is considered a main priority in many national health programs. Two vaccine strategies exist to protect infants from pertussis: “cocooning” and maternal vaccination during pregnancy. The latter is the more recent and preferred strategy, which protects newborns by passive transplacental transfer of pertussis antibodies. We review the reported evidence on the safety, effectiveness, timing and implementation of this antenatal immunization strategy.
Despite wide vaccination coverage with efficacious vaccines, pertussis is still not under control in any country. Two types of vaccines are available for the primary vaccination series, diphtheria/tetanus/whole-cell pertussis and diphtheria/tetanus/acellular pertussis vaccines, in addition to reduced antigen content vaccines recommended for booster vaccination. Using these vaccines, several strategies are being explored to counter the current pertussis problems, including repeated vaccination, cocoon vaccination and maternal immunization. With the exception of the latter, none have proven their effectiveness, and even maternal vaccination is not expected to ultimately control pertussis. Therefore, new pertussis vaccines are needed, and several candidates are in early pre-clinical development. They include whole-cell vaccines with low endotoxin content, outer membrane vesicles, new formulations, acellular vaccines with new adjuvants or additional antigens and live attenuated vaccines. The most advanced is the live attenuated nasal vaccine BPZE1. It provides strong protection in mice and non-human primates, is safe, even in immune compromised animals, and genetically stable after in vitro and in vivo passages. It also has interesting immunoregulatory properties without being immunosuppressive. It has successfully completed a first-in-man clinical trial, where it was found to be safe, able to transiently colonize the human respiratory tract and to induce immune responses in the colonized subjects. It is now undergoing further clinical development. As it is designed to reduce carriage and transmission of Bordetella pertussis, it may hopefully contribute to the ultimate control of pertussis.
Background:
In Germany, pertussis became notifiable in eastern federal states in 2002 and nationwide in March 2013. Infants are at greatest risk for severe disease, with a high proportion requiring hospitalization. We implemented enhanced hospital-based surveillance to estimate the incidence of pertussis requiring hospitalization among infants in Germany and to determine the proportion of infants hospitalized with pertussis too young to have been vaccinated.
Methods:
Enhanced surveillance was implemented within a nationwide hospital surveillance network (ESPED). We defined cases as children less than 1 year of age hospitalized due to laboratory-confirmed pertussis with disease onset from 01/07/2013-30/06/2015. We matched cases to those ascertained in the national statutory notification system, and estimated incidence using capture-recapture methodology.
Results:
The estimated annual incidence of pertussis requiring hospitalization in infants was 52/100,000 infants (95% confidence interval [CI] 48-57/100,000), with 39% under-reporting to the national notification system. During the two epidemiologic years under-reporting decreased from 46% to 32% and was lower in eastern than western federal states (21% vs. 40%). Within ESPED, 154 of 240 infants (64%) were younger than or still at the age recommended for the first vaccine dose; 55 (23%) could have received one or more vaccine doses. Median length of hospitalization was 9 days (IQR 5-13 days) and 18% required intensive care treatment.
Conclusions:
Our study revealed a high burden of pertussis in infants with marked under-reporting, especially in western federal states where notification was only recently established. Strategies for the prevention of severe pertussis especially among young infants should be revisited and potentially adapted.
Background on pregnancy and pertussis, new vs. old guidelines from the Centers for Disease . Systematic review of obstacles and recommendations to increase uptake during new recommended time of 27-36 weeks.
Background, old guidelines vs. new guidelines.Systematic review of obstacles, projected outcomes,, and recommendations.
Background and new guidelines vs. old guidelines. Systematic review of obstacles, recommendations, and conclusions.
Pertussis is a highly contagious infectious disease caused by Bordetella pertussis that can be extremely serious, particularly in young infants. For many years the efforts of health authorities throughout the world to prevent pertussis had the main goals of reducing the morbidity of infants and children under 5 years of age, maintaining protection for several years during the school-age period and developing a significant herd immunity to directly and indirectly reduce the risk of the spread of the disease among young infants and the risk of transmission of the infection from preschool children to infants. However, the increased risk of B. pertussis infection among adolescents and adults due to the waning immunity to this bacterium induced by vaccines and natural infection seems to be the main reason for the resurgence of pertussis. We discuss the reasons for the administration of pertussis vaccines to individuals for whom they were previously not recommended, the expected results of the administration of additional pertussis vaccine doses and the differences in the administration of pertussis vaccines in different countries. An analysis of the literature revealed several reports indicating the need for the modification of immunization schedules against pertussis, with booster doses among adolescents and the need for the vaccination of pregnant women. However, to monitor the true epidemiology of pertussis, effective programmes to collect pertussis cases, adequate reporting systems and vaccination coverage monitoring should be urgently implemented. © 2016 European Society of Clinical Microbiology and Infectious Diseases.
Influenza is a serious problem for infants <6 months of age, whose hospitalization rates for influenza and associated illness are comparable with rates in the elderly. Because influenza vaccines are not effective in this age group, the optimal evidence-based strategy is to administer trivalent inactivated influenza vaccines during pregnancy. Immunizing with trivalent inactivated influenza vaccines in the second and third trimester is well studied and safe, not only providing protection for the pregnant woman and her infant <6 months of age, but also for the fetus by decreasing the risk for low birth weight.
Influenza is a serious problem for infants <6 months of age, whose hospitalization rates for influenza and associated illness are comparable with rates in the elderly. Because influenza vaccines are not effective in this age group, the optimal evidence-based strategy is to administer trivalent inactivated influenza vaccines during pregnancy. Immunizing with trivalent inactivated influenza vaccines in the second and third trimester is well studied and safe, not only providing protection for the pregnant woman and her infant <6 months of age, but also for the fetus by decreasing the risk for low birth weight.
First described in the sixteenth century, whooping cough or pertussis is a relatively recent disease in human history, although some of the cough syndromes described in antiquity may in fact be pertussis-like diseases. Whooping cough caused by the gram-negative bacterium Bordetella pertussis is a severe respiratory disease, especially life-threatening in early childhood. In addition to respiratory symptoms, characterized by paroxysmal cough and whoop, pertussis also manifests itself by a marked leukocytosis, and complications due to superinfections are common. In adolescents, adults, and vaccinated older children, the disease is often atypical. It was a major cause of childhood mortality in the pre-vaccination era. Mass vaccination has tremendously reduced the incidence of the disease, but despite a large global vaccination coverage, we witness a dramatic increase of its incidence in recent years. The pathogenesis of the disease relies on a series of rather well-defined virulence factors, including several adhesins and toxins, whose production is controlled at the transcriptional level by a two-component master regulatory system. Various animal models have helped to decipher the virulence mechanisms of B. pertussis and have been instrumental in preclinical testing of vaccines. However, most of them do not reflect all the features of human pertussis, perhaps with the exception of a very recent baboon model. Since the discovery of its etiological agent, different diagnostic methods have been designed, including bacterial culture, serology, and, more recently, polymerase chain reaction. B. pertussis is sensitive to several antibiotics. Erythromycin is the drug of choice, and erythromycin-resistant B. pertussis isolates are rare. However, unless administered at the early catarrhal stage of the disease, antibiotic treatment is of little help to decrease the severity or to shorten the duration of the disease. Vaccination is today the most powerful tool to combat the disease. Several types of vaccines are currently available, including the whole-cell first-generation vaccines and the newer acellular second-generation vaccines. However, in view of the recent reemergence of pertussis, current vaccine regimens have shown their limits, and new vaccines are urgently needed. In that regard, live attenuated vaccines given very early in life may perhaps be able to protect the youngest and most vulnerable infants during the first months of life.
The development of acellular pertussis vaccines allowed since more than a decade to continue beyond the 2 first years of life the immunization against this illness. This technological progress should have led to an improvement in the control of the disease. However, despite high immunisation rates in infancy, Bordetella pertussis is still circulating in the population. Since 2010 a marked increase in the number of cases of whooping cough in infants too young to be vaccinated, as well as in older children and in teenagers, has been reported in a number of north-American states and in the United-Kingdom. A similar observation has been made in Belgium in 2012 and 2013. The limited duration of the protection resulting from vaccination is probably responsible for the insufficient control of the disease. The new approaches for the use of these vaccines that are proposed to protect the most vulnerable young infants will be discussed.
Vaccinating pregnant women and household contacts of infants is recommended for pertussis prevention. In structured abstraction of Web sites of Michigan birthing hospitals, we found only 36% contained any pertussis prevention information, and it usually required a specific search for pertussis. Hospitals should emphasize pertussis prevention as part of general information for expectant parents.
Copyright © 2014 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.
Pertussis is among the most poorly controlled bacterial vaccine-preventable diseases in the United States. In 2006, a tetanus, reduced-dose diphtheria, and acellular pertussis (Tdap) booster was recommended for adolescents and adults. Tdap vaccines were licensed on the basis of antibody response without vaccine effectiveness data.
From 30 September 2007 through 19 December 2007, a pertussis outbreak occurred at a nursery through twelfth grade school on St. Croix, US Virgin Islands. We screened all students for cough and collected clinical history, including Tdap receipt. Coughing students were offered diagnostic testing. We defined clinical case patients as students with cough 14 days in duration plus either whoop, paroxysms, or post-tussive vomiting, and we defined confirmed case patients as students with any cough with isolation of Bordetella pertussis or those with clinical cases and polymerase chain reaction or serological evidence of pertussis; other clinical cases were classified as probable.
There were 51 confirmed or probable cases among 499 students (attack rate, 10%). Disease clustered in grades 6-12, with a peak attack rate of 38% among 10th graders. Of 266 students aged 11 years with complete data, 31 (12%) had received Tdap. Forty-one unvaccinated students (18%) had confirmed or probable pertussis, compared with 2 (6%) of the vaccinated students (relative risk, 2.9); vaccine effectiveness was 65.6% (95% confidence interval, -35.8% to 91.3%; P = .092).
This first evaluation of Tdap vaccine effectiveness in the outbreak setting suggests that Tdap provides protection against pertussis. Increased coverage is needed to realize the full benefit of the vaccine program. Serological testing was an important tool for case identification and should be considered for inclusion in the Council of State and Territorial Epidemiologists case definition.
We conducted a population-based, nation-wide, prospective study to identify who introduced pertussis into the household of infants aged 6 months admitted to the hospital for pertussis in the Netherlands.
During the period 2006-2008, a total of 560 household contacts of 164 hospitalized infants were tested by polymerase chain reaction, culture, and serological examination to establish Bordetella pertussis infection. Clinical symptoms and vaccination history were obtained by a questionnaire submitted during sample collection and 4-6 weeks afterwards.
Overall, 299 household contacts (53%) had laboratory-confired pertussis; 159 (53%) had symptoms compatible with typical pertussis infection, and 42 (14%) had no symptoms. Among children vaccinated with a whole-cell vaccine, 17 (46%) of 37 had typical pertussis 1-3 years after completion of the primary series, compared with 9 (29%) of 31 children who had been completely vaccinated with an acellular vaccine. For 96 households (60%), the most likely source of infection of the infant was established, being a sibling (41%), mother (38%), or father (17%).
If immunity to pertussis in parents is maintained or boosted, 35%-55% of infant cases could be prevented. Furthermore, we found that, 1-3 years after vaccination with whole-cell or acellular vaccine, a significant percentage of children are again susceptible for typical pertussis. In the long term, pertussis vaccines and vaccination strategies should be improved to provide longer protection and prevent transmission.
For adults and adolescents (i.e., persons aged >/=13 years), the human immunodeficiency virus (HIV) infection classification system and the surveillance case definitions for HIV infection and acquired immunodeficiency syndrome (AIDS) have been revised and combined into a single case definition for HIV infection. In addition, the HIV infection case definition for children aged <13 years and the AIDS case definition for children aged 18 months to <13 years have been revised. No changes have been made to the HIV infection classification system, the 24 AIDS-defining conditions for children aged <13 years, or the AIDS case definition for children aged <18 months. These case definitions are intended for public health surveillance only and not as a guide for clinical diagnosis. Public health surveillance data are used primarily for monitoring the HIV epidemic and for planning on a population level, not for making clinical decisions for individual patients. CDC and the Council of State and Territorial Epidemiologists recommend that all states and territories conduct case surveillance of HIV infection and AIDS using the 2008 surveillance case definitions, effective immediately.
This study estimates the potential impact, on rates of pertussis infections, hospitalizations, and deaths among infants in the United States, of administering the first dose of diphtheria and tetanus toxoids and acellular pertussis vaccine at 6 weeks rather than 2 months of age.
We used existing data to estimate current US rates of pertussis infections, hospitalizations, and deaths according to age and infant population in 2004. We then estimated the potential impact of accelerating the administration of the first dose of diphtheria and tetanus toxoids and acellular pertussis vaccine from 2 months to 6 weeks of age, an alternative schedule consistent with current vaccination guidelines. We used Poisson distribution analysis to determine 95% confidence intervals for projected rates of pertussis disease.
Acceleration of administration of the first dose of diphtheria and tetanus toxoids and acellular pertussis vaccine from 2 months to 6 weeks of age is expected to prevent 1236 cases of pertussis, 898 hospitalizations, and 7 deaths attributable to pertussis per year in the United States. These decreases represent 9% reduction in cases, 9% reduction in hospitalizations, and 6% reduction in deaths attributable to pertussis among infants <3 months of age. Acceleration of the second and third doses by 2 weeks is expected to prevent an additional 923 cases, 520 hospitalizations, and 2 deaths attributable to pertussis each year.
Acceleration of administration of diphtheria and tetanus toxoids and acellular pertussis vaccine from 2 months to 6 weeks should reduce the burden of pertussis among young infants.
The origin of contamination in pertussis of young infants is generally the close relatives. From 2000 to 2004, only serology and culture were available in our hospital. The families of 16 young infants (age below one year) hospitalized for pertussis were screened using serological tests: 21/48 contacts were positive. After 2004, PCR was available for exploration of index cases and families: 35/85 contacts were positive. Of the mothers tested 23/46 were positive compared to 14/41 fathers. Only one parent presented with a typical paroxystic pertussis cough, 60% presented with a nonparoxystic cough having lasted for more than five days and 40% of positive adults did not present with cough. Despite official recommendations, none of these young parents had received an antipertussis booster vaccination. This study shows the high frequency of atypical or nonsymptomatic pertussis in adults in the close family of infected young infants. These adults contribute to spreading the disease.
Because young infants are at highest risk for severe pertussis and death and are also too young to have received the minimal
protective series of three doses of diphtheria-tetanus-pertussis (DTP) vaccine, we conducted a matched case-control study
to assess risk factors for pertussis among young infants during a pertussis outbreak in Chicago in 1993. We enrolled 39 cases
<7 months of age from a single teaching hospital and 96 controls, individually matched for age, from the well-child clinic
at the same hospital. Demographic characteristics, immunization status, and opportunities for disease exposure were analyzed
by means of conditional logistic regression. Cases and controls were similarly up to date with their DTP vaccinations (87%
and 89%, respectively). Infants of adolescent mothers (matched odds ratio [OR], 6.4; 95% confidence interval [CI], 1.3–41.4)
and infants of mothers who suffered ⩾7 days of cough during the child's incubation period (matched OR, 12.0; 95% CI, 1.4 to
infinity) were significantly more likely to have pertussis. Young mothers and mothers with a cough lasting ⩾7 days may be
an important source of pertussis infection for their young infants.
During the postvaccine era in Canada, most cases of pertussis have been reported in children <5 years of age, with the highest
incidence, morbidity, and mortality in infants <1 year old. Population-based data, with very high laboratory confirmation
rates and hospital separation and mortality statistics, chronicle the changing age and seasonal profile associated with pertussis
over recent successive outbreaks in British Columbia, Canada. A large outbreak during 2000 highlights 2 important changes
to the postvaccine profile. For the first time in Canada, the incidence of pertussis among preteens and teens surpassed that
of all other age groups. At the same time, a decreasing incidence of pertussis among infants and preschool children highlights
reduced susceptibility in the very young. Recent changes in the childhood immunization program (including introduction of
an acellular pertussis vaccine), waning immunity, and changes in laboratory methods are considered in explaining these 2 simultaneous
but divergent trends in the pertussis profile.
To diagnose pertussis using culture, polymerase chain reaction, and serology, in children admitted to intensive care units (PICUs) and some paediatric wards in London, and in their household contacts to determine the source of infection.
Infants <5 months old admitted to London PICUs between 1998 and 2000 with respiratory failure, apnoea and/or bradycardia, or acute life threatening episodes (ALTE), and children <15 years admitted to paediatric wards at St Mary's and St George's Hospitals between 1999 and 2000 with lower respiratory tract infection, apnoea, or ALTE were studied.
Sixty seven per cent of eligible children (142/212) were recruited; 23% (33/142) had pertussis, 19.8% (25/126) on the PICU and 50% (8/16) on wards. Two died. Only 4% (6/142) were culture positive. Pertussis was clinically suspected on admission in 28% of infants (7/25) on the PICU and 75% (6/8) on the wards. Infants on PICU with pertussis coughed for longer, had apnoeas and whooped more often, and a higher lymphocyte count than infants without pertussis. Pertussis and respiratory syncytial virus (RSV) co-infection was frequent (11/33, 33%). Pertussis was confirmed in 22/33 (67%) of those who were first to become ill in the family. For 14/33 children the source of infection was a parent; for 9/33 the source of pertussis was an older fully vaccinated child in the household.
Severe pertussis is under diagnosed. An RSV diagnosis does not exclude pertussis. Future changes to the UK vaccination programme should aim to reduce pertussis transmission to young infants by their parents and older siblings.
Reported cases of pertussis among adolescents and adults have increased since the 1980s, despite increasingly high rates of vaccination among infants and children. However, severe pertussis morbidity and mortality occur primarily among infants.
To describe the trends and characteristics of reported cases of pertussis among infants younger than 12 months in the United States from 1980 to 1999.
Cases of pertussis in infants younger than 12 months in the United States reported to the National Notifiable Disease Surveillance System of the Centers for Disease Control and Prevention between 1980 and 1999, and detailed case data from the Supplementary Pertussis Surveillance System.
Incidence and demographic and clinical characteristics of cases.
The incidence of reported cases of pertussis among infants increased 49% in the 1990s compared with the incidence in the 1980s (19 798 vs 12 550 cases reported; 51.1 cases vs 34.2 cases per 100 000 infant population, respectively). Increases in the incidence of cases and the number of deaths among infants during the 1990s primarily were among those aged 4 months or younger, contrasting with a stable incidence of cases among infants aged 5 months or older. The proportion of cases confirmed by bacterial culture was higher in the 1990s than in the 1980s (50% and 33%, respectively); the proportion of hospitalized cases was unchanged (67% vs 68%, respectively). Receipt of fewer doses of vaccine was associated with hospitalization, when cases were stratified by age in months.
The incidence of reported cases of pertussis among infants increased in the 1990s compared with the 1980s. The limited age group affected, the increased rate of bacteriologic confirmation, and the unchanged severity of illness suggest that an increase in infant pertussis has occurred apart from any change in reporting. Strategies are needed to prevent the morbidity and mortality from pertussis among infants too young to be fully vaccinated, according to the current recommended schedules of vaccination in the United States.
Pertussis immunization of adults may be necessary to improve the control of a rising burden of disease and infection. This trial of an acellular pertussis vaccine among adolescents and adults evaluated the incidence of pertussis, vaccine safety, immunogenicity, and protective efficacy.
Bordetella pertussis infections and illnesses were prospectively assessed in 2781 healthy subjects between the ages of 15 and 65 years who were enrolled in a national multicenter, randomized, double-blind trial of an acellular pertussis vaccine. Subjects received either a dose of a tricomponent acellular pertussis vaccine or a hepatitis A vaccine (control) and were monitored for 2.5 years for illnesses with cough that lasted for more than 5 days. Each illness was evaluated with use of a nasopharyngeal aspirate for culture and polymerase-chain-reaction assay, and serum samples from patients in both acute and convalescent stages of illness were analyzed for changes in antibodies to nine B. pertussis antigens.
Of the 2781 subjects, 1391 received the acellular pertussis vaccine and 1390 received the control vaccine. The groups had similar ages and demographic characteristics, and the median duration of follow-up was 22 months. The acellular pertussis vaccine was safe and immunogenic. There were 2672 prolonged illnesses with cough, but the incidence of this nonspecific outcome did not vary between the groups, even when stratified according to age, season, and duration of cough. On the basis of the primary pertussis case definition, vaccine protection was 92 percent (95 percent confidence interval, 32 to 99 percent). Among unimmunized controls with illness, 0.7 percent to 5.7 percent had B. pertussis infection, and the percentage increased with the duration of cough. On the basis of other case definitions, the incidence of pertussis in the controls ranged from 370 to 450 cases per 100,000 person-years.
The acellular pertussis vaccine was protective among adolescents and adults, and its routine use might reduce the overall disease burden and transmission to children.
In Australia in 1999 acellular pertussis vaccine (DTPa) replaced locally manufactured whole cell vaccine given at 2, 4 and 6 months of age with coverage of about 95% by 12 months of age. Few data are available on pertussis hospitalizations or sources of infection in countries exclusively using DTPa.
In 2001 national active monthly surveillance of infant hospitalizations for pertussis was conducted through the Australian Pediatric Surveillance Unit, which surveys all child health specialists monthly. A standard questionnaire was completed for notified cases.
There were 140 infants reported (median age at diagnosis, 8 weeks). The rate of hospitalization in indigenous infants was significantly higher than in nonindigenous infants (P < 0.01). Of 97 (69%) infants who had not been vaccinated for pertussis, 63 (65%) were <8 weeks old (before the first scheduled dose of DTPa vaccine). Of 76 infants age > or =8 weeks, only 28 (37%) were appropriately immunized for age. Of 68 coughing contacts whose ages were known, 46 (68%) were adults, usually one of the infant's parents. Of 32 child contacts 16 (50%) were siblings. Four infants <6 weeks old died.
Despite universal vaccination with DTPa in Australia, pertussis remains an important cause of hospitalization, morbidity and death in infants, most of whom were too young to be vaccinated or had missed vaccinations. The most common source of infection was a parent. Strategies to improve pertussis control in countries with high DTPa coverage could include adult-formulated booster pertussis vaccines for adolescents and recent parents and/or accelerated pertussis vaccine schedules for infants.
These recommendations for human immunodeficiency virus (HIV) testing are intended for all health-care providers in the public and private sectors, including those working in hospital emergency departments, urgent care clinics, inpatient services, substance abuse treatment clinics, public health clinics, community clinics, correctional health-care facilities, and primary care settings. The recommendations address HIV testing in health-care settings only. They do not modify existing guidelines concerning HIV counseling, testing, and referral for persons at high risk for HIV who seek or receive HIV testing in nonclinical settings (e.g., community-based organizations, outreach settings, or mobile vans). The objectives of these recommendations are to increase HIV screening of patients, including pregnant women, in health-care settings; foster earlier detection of HIV infection; identify and counsel persons with unrecognized HIV infection and link them to clinical and prevention services; and further reduce perinatal transmission of HIV in the United States. These revised recommendations update previous recommendations for HIV testing in health-care settings and for screening of pregnant women (CDC. Recommendations for HIV testing services for inpatients and outpatients in acute-care hospital settings. MMWR 1993;42[No. RR-2]:1-10; CDC. Revised guidelines for HIV counseling, testing, and referral. MMWR 2001;50[No. RR-19]:1-62; and CDC. Revised recommendations for HIV screening of pregnant women. MMWR 2001;50[No. RR-19]:63-85). Major revisions from previously published guidelines are as follows: For patients in all health-care settings HIV screening is recommended for patients in all health-care settings after the patient is notified that testing will be performed unless the patient declines (opt-out screening). Persons at high risk for HIV infection should be screened for HIV at least annually. Separate written consent for HIV testing should not be required; general consent for medical care should be considered sufficient to encompass consent for HIV testing. Prevention counseling should not be required with HIV diagnostic testing or as part of HIV screening programs in health-care settings. For pregnant women HIV screening should be included in the routine panel of prenatal screening tests for all pregnant women. HIV screening is recommended after the patient is notified that testing will be performed unless the patient declines (opt-out screening). Separate written consent for HIV testing should not be required; general consent for medical care should be considered sufficient to encompass consent for HIV testing. Repeat screening in the third trimester is recommended in certain jurisdictions with elevated rates of HIV infection among pregnant women.
We present 10 years of results from a paediatrician hospital network surveillance in France, set up in 1996 to monitor the trend of pertussis (whooping cough) in children and the impact of the vaccination strategies. Microbiologists from 43 hospitals that participate in the network on a voluntary basis notify pertussis diagnosis, and paediatricians complete a questionnaire for the infants under 6 months that fulfil the microbiological, clinical or epidemiological case definition. The network covers about 30% of pertussis cases seen in French hospitals.
In 2005, two tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccines were licensed and recommended for use in adults and adolescents in the United States: ADACEL (sanofi pasteur, Swiftwater, Pennsylvania), which is licensed for use in persons aged 11--64 years, and BOOSTRIX (GlaxoSmithKline Biologicals, Rixensart, Belgium), which is licensed for use in persons aged 10-18 years. Both Tdap vaccines are licensed for single-dose use to add protection against pertussis and to replace the next dose of tetanus and diphtheria toxoids vaccine (Td). Available evidence does not address the safety of Tdap for pregnant women, their fetuses, or pregnancy outcomes sufficiently. Available data also do not indicate whether Tdap-induced transplacental maternal antibodies provide early protection against pertussis to infants or interfere with an infant's immune responses to routinely administered pediatric vaccines. Until additional information is available, CDC's Advisory Committee on Immunization Practices recommends that pregnant women who were not vaccinated previously with Tdap: 1) receive Tdap in the immediate postpartum period before discharge from hospital or birthing center, 2) may receive Tdap at an interval as short as 2 years since the most recent Td vaccine, 3) receive Td during pregnancy for tetanus and diphtheria protection when indicated, or 4) defer the Td vaccine indicated during pregnancy to substitute Tdap vaccine in the immediate postpartum period if the woman is likely to have sufficient protection against tetanus and diphtheria. Although pregnancy is not a contraindication for receiving Tdap vaccine, health-care providers should weigh the theoretical risks and benefits before choosing to administer Tdap vaccine to a pregnant woman. This report 1) describes the clinical features of pertussis, tetanus, and diphtheria among pregnant and postpartum women and their infants, 2) reviews available evidence of pertussis vaccination during pregnancy as a strategy to prevent infant pertussis, 3) summarizes Tdap vaccination policy in the United States, and 4) presents recommendations for use of Td and Tdap vaccines among pregnant and postpartum women.
Since 2004, in France, pertussis booster is recommended in parents of young infants and adults likely to become parents. This recommendation adds to others such as rubella vaccination in unvaccinated or seronegative women and decennial dT–IPV booster. The objective of this study is to evaluate the impact of these recommendations in parents of young infants. Pediatricians had to include parents of infants at the first well-baby visit after birth. Vaccination data were secondary recorded from parent's health record or called upon their memory. Between June and October 2006, 41 pediatricians included parents of 400 infants (median age: 36 days). dT–IPV booster was recorded or recalled in 37.4% within the 10 previous years and 17.7% within the 3 previous years. Among this last group, only 11.8% had received a combination including pertussis. Rubella serology was declared as positive by 94% of the mothers, but the physicians obtained the information of a previous rubella vaccination in only 71.7% of the mothers. Among the 9 seronegative mothers during pregnancy, only 3 were vaccinated in postpartum. Adults' immunization guidelines are not well known and poorly applied in France. The unavailability of monovalent pertussis vaccine reduces the eligible population. Two years after the launch of the pertussis cocoon strategy, the coverage of eligible young parents remains low and many opportunities are too frequently missed on the opportunity of decenial dTPolio booster. Rubella catch up strategy should be improved. Adults' vaccination strategies and guidelines need to be better broadcasted to health care professionals and also families.
The origin of contamination in pertussis of young infants is generally the close relatives. From 2000 to 2004, only serology and culture were available in our hospital. The families of 16 young infants (age below one year) hospitalized for pertussis were screened using serological tests: 21/48 contacts were positive. After 2004, PCR was available for exploration of index cases and families: 35/85 contacts were positive. Of the mothers tested 23/46 were positive compared to 14/41 fathers. Only one parent presented with a typical paroxystic pertussis cough, 60% presented with a nonparoxystic cough having lasted for more than five days and 40% of positive adults did not present with cough. Despite official recommendations, none of these young parents had received an antipertussis booster vaccination. This study shows the high frequency of atypical or nonsymptomatic pertussis in adults in the close family of infected young infants. These adults contribute to spreading the disease.
To describe the epidemiology of infant pertussis in King County, Washington, and to better understand the implications for tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccination among older children, adolescents, and adults.
Retrospective analysis of reported pertussis cases among infants younger than 1 year, January 1, 2002, through December 31, 2007.
King County, Washington.
Reported pertussis cases among infants younger than 1 year between 2002 and 2007.
Bordetella pertussis from a household member or close contact was the primary exposure. The main outcome measures were age and vaccination status, incidence by race/ethnicity, suspected exposure, and Tdap eligibility of household members and close contacts.
Among 176 confirmed cases of infants with pertussis, the median age was 3 months (age range, 0-11 months); 80.1% were younger than 6 months. Seventy-seven percent were age-appropriately vaccinated. Between 2002 and 2007, the overall mean annual incidence was 136 cases per 100,000 infant population. Compared with a mean annual incidence of 73 cases per 100,000 infant population among whites, the incidence was 246 cases per 100,000 infant population among blacks (rate ratio [RR], 3.37; 95% confidence interval [CI], 2.59-4.44) and 194 cases per 100,000 infant population among Hispanics (RR, 2.66; 95% CI, 2.02-3.53). Households were the suspected exposure location for 70.0% of cases. Case households had a median of 3 (range, 1-15) Tdap-eligible persons.
The burden of infant pertussis in King County, Washington, was high between 2002 and 2007, especially among racial/ethnic minorities. Tdap vaccination of eligible household members and close contacts should be promoted as an additional means of protecting infants from pertussis.
Vaccine effectiveness in the first large-scale use of adolescent pertussis vaccine in Australia was evaluated by the screening method. Vaccine effectiveness was 78.0% (95% CI: 60.7-87.6%) for all study cases (n = 167), increasing to 85.4% (95% CI: 83.0-87.5%) for laboratory-confirmed cases (n = 155). Effectiveness should be comparable in settings with similar programs, such as the United States and Canada.
Household contacts of primary pertussis cases were evaluated. Infection was determined by culture, direct fluorescent antibody
assay, and serological criteria. Agglutinin titers and values of ELISA IgG and IgA antibodies to lymphocytosis-promoting factor,
filamentous hemagglutinin, and pertactin were determined. In 39 households 255 subjects were exposed; 114 remained well (group
1), 53 had mild illness (group 2), and 88 had pertussis (group 3). The infection rates were 46% (group 1), 43% (group 2),
and 80% (group 3). In a subgroup of subjects seen within 14–28 days of exposure, it was found that none with clinical pertussis
had a value of IgG antibody to pertactin in acute-phase sera of ⩾50 ELISA units (EU) per mL or an agglutinin titer of >256.
Of the primary cases, 53% were ⩾13 years of age. These data point out the importance of Bordetella pertussis infections in adolescents and adults as a source of infection in young children. Our subgroup data suggest that high values
of antibody to pertactin and high agglutinin titers may be predictive of protection against clinical pertussis.
Pertussis has re-emerged as a public health problem in Canada in recent years, emphasizing concerns about the effectiveness of the currently licensed whole-cell vaccine. Following a 1994 outbreak in Nova Scotia, we conducted a case-control study of 483 children aged < 10 years to assess vaccine effectiveness. Ninety-three percent of children aged 6 months and above had received three or more doses of vaccine, however, only 78% had received age-appropriate immunization. Among children aged 4 years and more, vaccine effectiveness against laboratory-confirmed pertussis was 57% (95% CI, 23-77%) for age-appropriate immunization (five doses) vs partial or no immunization. Vaccine effectiveness increased with increasing number of doses from 25% (95% CI, -58-65%) for three or more doses to 55% (95% CI, -15-83%) for five doses, compared with 0-2 doses.
Despite widespread vaccination during 30 years, the hypothesis of a resurgence of pertussis in France has been raised by outbreaks and sporadic case reports. No surveillance data were available after 1985.
A survey was undertaken in 1993 and 1994 in a pediatric hospital network able to confirm cases; the network (22 hospitals) represents 19.6% of pediatric admissions in France. Case definition included clinical (> or = 21 days of paroxysmal cough), laboratory-confirmed (culture or serology by immunoblot) or epidemiologically confirmed pertussis (documented contact with a laboratory-confirmed case). The pattern of transmission was studied in the household. Vaccine status was obtained from health records.
during a 15-month period 560 cases (316 index cases, 244 household contact cases) were reported; 49% of index cases and 20% of contact cases were confirmed by culture and/or serology. Sixty-five percent of index cases were younger than 1 year of age (the incidence in this age group could be estimated to be 95/100000) and 66% were hospitalized for a mean duration of 2 weeks. Infection was acquired from parents (34%) and siblings (46%). Seventy-three percent of index cases were unvaccinated.
Although pertussis vaccination coverage is very high in France, the organism is still circulating, affecting, within the pediatric population, mostly non- or incompletely vaccinated infants. These results strongly support the importance of adhering to the immunization schedule and suggest introducing booster dose(s) to prolong vaccine immunity and reduce the exposure to Bordetella pertussis of infants too young to be immunized.
To assess the morbidity associated with the continued high levels of pertussis, we studied all children .2 years of age who
were admitted to the 11 Immunization Monitoring Program-Active (IMPACT) centers, which constitute 85% of Canada's tertiary
care pediatric beds. In the 7 years preceding implementation of acellular pertussis vaccine, a total of 1,082 pertussis cases
were reported, of which 49.1% were culture-confirmed. The median age of the patients was 12.4 weeks; 78.9% of cases were in
children <6 months of age. Complications of pertussis were common: pneumonia was reported in 9.4% of cases, new seizures in
2.3%, and encephalopathy in 0.5%. There were 10 deaths (0.9%), all in children ⩽6 months of age. Duration of hospitalization
was longer (9.3 days vs. 4.9 days; P = .001) and intensive care was required more frequently (19.2% vs. 4.9%; P = .001) in infants under <6 months of age than in those ⩾6 months. Pertussis continues to cause significant morbidity and
occasional mortality in Canada, particularly in young infants.
Pertussis is increasingly being recognized as an important cause of cough illness in adolescents and adults. To evaluate the safety and immunogenicity of an adult formulation of a five-component (pertussis toxoid, filamentous hemagglutinin, pertactin, fimbriae 2 and 3) acellular pertussis vaccine combined with diphtheria and tetanus toxoids, we randomly allocated 749 healthy adolescents and adults from 12-54 years of age recruited from five Canadian communities to receive either tetanus-diphtheria vaccine (Td), acellular pertussis vaccine (aP) or combined diphtheria-tetanus-acellular pertussis vaccine (TdaP). Subjects and personnel were unaware of the vaccine allocation. Antibody levels were measured before and one month postimmunization; adverse events were collected at 24 and 72 h and 8 to 10 days. Adverse events were reported in similar frequency amongst the three vaccine groups. Moderate pain at the injection site was reported less frequently in the aP group than the TdaP group (10.7% compared to 19.4%; relative risk 0.6, 95% confidence interval 0.3-0.9). Chills were reported less frequently after Td (5.3%) than after TdaP (12.5%; relative risk 0.4, 95% confidence interval 0.2-0.9). There were no statistically significant differences between recipients of Td and TdaP in tetanus and diphtheria antitoxin levels achieved. Antibody response against Bordetella pertussis antigens was vigorous in all groups although recipients of aP alone had higher levels of antibody levels against pertussis toxoid, fimbriae, and agglutinins and lower antibody levels against pertactin than did TdaP recipients. We conclude that this adult formulation 5-component acellular pertussis vaccine is safe and immunogenic in adolescents and adults and is a candidate vaccine for adolescent and adult immunization programs.
Beginning in 1990 Canada experienced a resurgence of pertussis. Changes in incidence and hospitalization according to age in the province of Quebec between 1983 and 1998 were examined to assess the presence of a cohort effect resulting from a poorly protective vaccine.
The source of data on incident cases was pertussis notifications to the Quebec Ministry of Health and Social Services. Hospitalization data were extracted from the administrative database that collects information on each hospitalization.
The mean annual incidence before 1990 was 3.8 cases per 100,000 population which increased to 37.2 thereafter. Infants had the smallest increase (2.7-fold) when compared with children between 1 and 19 years who experienced a 9- to 15-fold increase and with adults (22.5-fold). The mean annual hospitalization rates increased from 2.7 per 100,000 before 1990 to 5.2 afterward. Ninety percent of hospitalizations occurred in children <5 years of age. The proportion of cases in 0- to 4-year-old children decreased, whereas it increased steadily in all other age groups during the entire study period. Between 1990 and 1998 the median age of cases shifted from 4.4 to 7.8 years. Pertussis affected predominantly children who were immunized with a vaccine introduced in the mid-1980s. The evolution of the age distribution of cases paralleled the aging of this cohort with a slow but steady drift of disease from early childhood to adolescence.
The sudden increase in pertussis incidence in Canada can be largely attributed to a cohort effect resulting from a poorly protective pertussis vaccine used between 1985 and 1998.
To describe the clinical course of fatal cases of pertussis and identify predictors of death at the time of presentation for medical care.
Case-control study of 16 deaths from pertussis identified by the Immunization Monitoring Program, Active (IMPACT) surveillance network (January 1991-December 2001) matched with 32 nonfatal cases by age, date, and geography. Differences were compared by Fisher exact test and logistic regression. A multivariate model was developed using stepwise logistic regression.
All 16 fatal cases were < or =6 months old; 13 were <2 months old. Fatal cases were less likely to have had cough complications during pregnancy (48% vs 14%; P=.046) and more likely to have pneumonia (63% vs 16%; P=.0024) before hospital admission and more likely to have seizures, pneumonia, leukocytosis, and hypoxemia after admission (P<.001 for all comparisons). White blood cell count and pneumonia were independent predictors of fatal outcome in the multivariate model.
Infants too young to have begun their immunizations are at highest risk of fatal pertussis infection. Leukocytosis and pneumonia are predictors of a poor outcome; however, rapid progression of the disease may make interventions difficult.
In the United States in the 1990s, the incidence of reported pertussis in adults, adolescents and infants increased; infants younger than 1 year of age had the highest reported incidence.
In 4 states with Enhanced Pertussis Surveillance, we examined the epidemiology of reported pertussis cases to determine the source of pertussis among infants. A source was defined as a person with an acute cough illness who had contact with the case-infant 7-20 days before the infant's onset of cough.
The average annual pertussis incidence per 100,000 infants younger than 1 year of age varied by state: 22.9 in Georgia; 42.1 in Illinois; 93.0 in Minnesota; and 35.8 in Massachusetts. Family members of 616 (80%) of 774 reported case-infants were interviewed; a source was identified for 264 (43%) of the 616 case-infants. Among the 264 case-infants, mothers were the source for 84 (32%) and another family member was the source for 113 (43%). Of the 219 source-persons with known age, 38 (17%) were age 0-4 years, 16 (7%) were age 5-9 years, 43 (20%) were age 10-19 years, 45 (21%) were age 20-29 years and 77 (35%) were age > or =30 years.
The variation in reported pertussis incidence in the 4 states might have resulted from differences in awareness of pertussis among health care providers, diagnostic capacity and case classification. Among case-infants with an identifiable source, family members (at any age) were the main source of pertussis. Understanding the source of pertussis transmission to infants may provide new approaches to prevent pertussis in the most vulnerable infants.
Between July 1997 and April 1998, universal childhood immunization programs in Canada changed from using a whole-cell pertussis to a 5-component acellular pertussis-containing vaccine. To assess effects on pertussis epidemiology of this nationwide change, we analyzed hospitalizations during 1991-2004 using the Canadian Immunization Monitoring Program, Active (IMPACT) pertussis database.
IMPACT is an active surveillance network based in 12 pediatric tertiary-care hospitals across Canada. Characteristics of hospitalized cases of pertussis were compared by type of vaccine received or by birth date (if immunization records were unavailable or the child was unvaccinated). Age-stratified incidence rates were calculated by year and vaccine type.
Two thousand ninety-six cases of pertussis were admitted to IMPACT centers, 1174 during the whole-cell vaccine program (WCV-P) and 842 during the acellular vaccine program (ACV-P). Pertussis incidence among children <5 years old decreased significantly during the ACV-P, causing an increase in the residual proportion of cases either too young to be immunized (<2 months old: ACV-P 39% versus WCV-P 26.1%; P < 0.0001) or too young for a second dose (2-3 months old: 42.9% versus 34.2%, respectively; P < 0.0001). A significantly smaller proportion of cases (ACV-P 15.1% versus WCV-P 27.3%) occurred in infants who were old enough (4-11 months of age) to have received 2 or 3 doses of vaccine.
With ACV-P, pertussis hospitalizations in children 4-59 months old decreased in frequency, consistent with improved vaccine effectiveness, but remained prominent among very young infants. Improved control strategies are needed to reduce infections among infants too young for pertussis vaccination.
Pertussis vaccination has reduced the number of notified cases in industrialized countries from peak years by more than 95%. The effect of recently recommended adult and adolescent vaccination strategies on infant pertussis depends, in part, on the proportion of infants infected by adults and adolescents. This proportion, however, remains unclear, because studies have not been able to determine the source case for 47%-60% of infant cases.
A prospective international multicenter study was conducted of laboratory confirmed infant pertussis cases (aged <or=6 months) and their household and nonhousehold contacts. Comprehensive diagnostic evaluation (including PCR and serology) was performed on all participants independent of symptoms. Source cases were identified and described by relationship to the infant, age and household status.
The study population comprised 95 index cases and 404 contacts. The source of pertussis was identified for 48% of infants in the primary analysis and up to 78% in sensitivity analyses. In the primary analysis, parents accounted for 55% of source cases, followed by siblings (16%), aunts/uncles (10%), friends/cousins (10%), grandparents (6%) and part-time caretakers (2%). The distribution of source cases was robust to sensitivity analyses.
This study provides solid evidence that among infants for whom a source case was identified, household members were responsible for 76%-83% of transmission of Bordetella pertussis to this high-risk group. Vaccination of adolescents and adults in close contact with young infants may thus eliminate a substantial proportion of infant pertussis if high coverage rates can be achieved.
Increased incidence of pertussis has been noted among infants too young to be immunized. We studied the disease burden of pertussis in pediatric intensive care units and the source of infection in several Asian, European and Latin American countries.
The study was conducted in 7 countries from September 2001 to January 2004. Children <1 year of age were enrolled from pediatric intensive care units (PICU) and pediatric wards if they presented with respiratory failure, apnea, bradycardia, or cough accompanied by paroxysms, vomiting, whoop or cyanosis. Household members of pertussis-positive index cases were asked to answer a questionnaire and provide diagnostic specimens.
Pertussis was confirmed in 99 infants (12%) of 823 infants included in the analysis: 10 of 90 (11%) in Brazil, 9 of 88 (10%) in Costa Rica, 11 of 145 (8%) in Germany, 13 of 147 (9%) in Singapore, 29 of 67 (43%) in Spain, 2 of 86 (2%) in Taiwan and 25 of 200 (13%) in Uruguay. However, sensitivity analysis indicated that these figures were conservative. The mean (+/- SD) average age of infection was 2.6 +/- 2.2 months. Pertussis was found among 96 of 269 (36%) of household contacts investigated. At least one household contact was identified as the source of infection in 24 of 88 (27%) of the PICU cases and mothers were identified as being the most frequent source of infection.
Although regional differences exist, severe pertussis represents a considerable global disease burden. Since most infants are infected before vaccination and concomitant protection is completed, household contacts should be targeted for booster vaccination to reduce the pertussis reservoir.
Since 2004, in France, pertussis booster is recommended in parents of young infants and adults likely to become parents. This recommendation adds to others such as rubella vaccination in unvaccinated or seronegative women and decennial dT-IPV booster. The objective of this study is to evaluate the impact of these recommendations in parents of young infants. Pediatricians had to include parents of infants at the first well-baby visit after birth. Vaccination data were secondary recorded from parent's health record or called upon their memory. Between June and October 2006, 41 pediatricians included parents of 400 infants (median age: 36 days). dT-IPV booster was recorded or recalled in 37.4% within the 10 previous years and 17.7% within the 3 previous years. Among this last group, only 11.8% had received a combination including pertussis. Rubella serology was declared as positive by 94% of the mothers, but the physicians obtained the information of a previous rubella vaccination in only 71.7% of the mothers. Among the 9 seronegative mothers during pregnancy, only 3 were vaccinated in postpartum. Adults' immunization guidelines are not well known and poorly applied in France. The unavailability of monovalent pertussis vaccine reduces the eligible population. Two years after the launch of the pertussis cocoon strategy, the coverage of eligible young parents remains low and many opportunities are too frequently missed on the opportunity of decenial dTPolio booster. Rubella catch up strategy should be improved. Adults' vaccination strategies and guidelines need to be better broadcasted to health care professionals and also families.
Public Health Agency of Canada
Public Health Agency of Canada. Final report of outcomes from the
National Consensus Conference for Vaccine-Preventable Diseases in
Canada. Pertussis. Can Commun Dis Rep 2007; 33(Suppl 3):33-9.
National Advisory Committee on Immunization. Prevention of pertussis in adolescents and adults
National Advisory Committee on Immunization. Prevention of pertussis
in adolescents and adults. Can Commun Dis Rep 2003; 29(ACS-5,6):1-9.
N, approaches infinity; hosp, hospital; ICU, intensive care unit; NNV, number needed to vaccinate. a Assumes 85% parent vaccine effectiveness in preventing all infant serious outcomes. References 1 Changing epidemiology and emerging risk groups for pertussis
Low hosp (2007)
4/0
9/0
71 353//N
45 406//N
Abbreviations: /N, approaches infinity; hosp, hospital; ICU, intensive care unit; NNV, number needed to vaccinate.
a Assumes 85% parent vaccine effectiveness in preventing all infant serious outcomes.
References
1. Galanis E, King AS, Varughese P, Halperin SA. Changing epidemiology
and emerging risk groups for pertussis. CMAJ 2006; 174:451–2.
Canadian vital statistics Available at