Madhumita Shrotri

Madhumita Shrotri
University College London | UCL · Institute of Health Informatics

Master of Public Health

About

63
Publications
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1,306
Citations

Publications

Publications (63)
Article
Full-text available
We studied humoral and cellular immunity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in 152 long-term care facility staff and 124 residents over a prospective 4-month period shortly after the first wave of infection in England. We show that residents of long-term care facilities developed high and stable levels of antibodie...
Article
Full-text available
Background The SARS-CoV-2 omicron variant (B.1.1.529) is highly transmissible, but disease severity appears to be reduced compared with previous variants such as alpha and delta. We investigated the risk of severe outcomes following infection in residents of long-term care facilities. Methods We did a prospective cohort study in residents of long-...
Article
Full-text available
Objectives: Risk of SARS-CoV-2 infection varies across occupations; however, investigation into factors underlying differential risk is limited. We aimed to estimate the total effect of occupation on SARS-CoV-2 serological status, whether this is mediated by workplace close contact, and how exposure to poorly ventilated workplaces varied across oc...
Preprint
Third dose COVID-19 vaccines are being deployed widely but their efficacy has not been assessed adequately in vulnerable elderly people who exhibit suboptimal responses after primary series vaccination. We studied spike-specific immune responses in 341 staff and residents in long-term care facilities (LTCF) who received an mRNA vaccine following du...
Preprint
Background Respiratory viruses, including SARS-CoV-2, can infect the eyes or pass into the nose via the nasolacrimal duct. The importance of transmission via the eyes is unknown but might plausibly be reduced in those who wear glasses. Previous studies have mainly focussed on protective eyewear in healthcare settings. Methods Participants from the...
Preprint
Background Long-term care facilities (LTCF) have been prioritised for vaccination, but data on potential waning of vaccine effectiveness (VE) and the impact of booster doses in this vulnerable population remains scarce. Methods We included residents and staff from 331 LTCFs enrolled in VIVALDI ( ISRCTN 14447421 ), who underwent routine PCR testing...
Article
Background: Understanding symptomatology and accuracy of clinical case definitions for community COVID-19 cases is important for Test, Trace and Isolate (TTI) and future targeting of early antiviral treatment. Methods: Community cohort participants prospectively recorded daily symptoms and swab results (mainly undertaken through the UK TTI system)....
Preprint
The two most commonly-used SARS-CoV-2 vaccines in the UK, BNT162b2 (Pfizer-BioNTech) and ChAdOx1 nCoV-19 (Oxford-AstraZeneca), employ different immunogenic mechanisms. Compared to BNT162b2, two-dose immunisation with ChAdOx1 induces substantially lower peak anti-spike antibody (anti-S) levels and is associated with a higher risk of breakthrough inf...
Preprint
Full-text available
Importance The Omicron (B.1.1.529) variant has increased SARs-CoV-2 infections in double vaccinated individuals globally, particularly in ChAdOx1 recipients. To tackle rising infections, the UK accelerated booster vaccination programmes used mRNA vaccines irrespective of an individual’s primary course vaccine type with booster doses rolled out acco...
Preprint
Introduction Seroprevalence studies can provide a measure of cumulative incidence of SARS-CoV-2 infection, but a better understanding of antibody dynamics following infection is needed to assess longevity of detectability. Infection is characterised by detection of spike (anti-S) and nucleocapsid (anti-N) antibodies, whereas vaccination only stimul...
Preprint
Background It is poorly understood which workers lack access to sick pay in England and Wales. This evidence gap has been of particular interest in the context of the Covid-19 epidemic given the relationship between presenteeism and infectious disease transmission. Method This cross-sectional analysis is nested within a large community cohort stud...
Preprint
Background Recently there has been a rapid, global increase in SARS-CoV-2 infections associated with the Omicron variant (B.1.1.529). Although severity of Omicron cases may be reduced, the scale of infection suggests hospital admissions and deaths may be substantial. Definitive conclusions about disease severity require evidence from populations wi...
Preprint
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Introduction: Infections of SARS-CoV-2 in vaccinated individuals have been increasing globally. Understanding the associations between vaccine type and a post-vaccination infection could help prevent further COVID-19 waves. In this paper, we use trial emulation to understand the impact of a phased introduction of the vaccine in the UK driven by vul...
Article
Introduction: Increased transmissibility of B.1.1.7 variant of concern (VOC) in the UK may explain its rapid emergence and global spread. We analysed data from putative household infector - infectee pairs in the Virus Watch Community cohort study to assess the serial interval of COVID-19 and whether this was affected by emergence of the B.1.1.7 var...
Article
Background: Household overcrowding is associated with increased risk of infectious diseases across contexts and countries. Limited data exist linking household overcrowding and risk of COVID-19. We used data collected from the Virus Watch cohort to examine the association between overcrowded households and SARS-CoV-2. Methods: The Virus Watch stud...
Article
Full-text available
Background: Long-term care facilities (LTCFs) have reported high SARS-CoV-2 infection rates and related mortality, but the proportion of infected people among those who have survived, and duration of the antibody response to natural infection, is unknown. We determined the prevalence and stability of nucleocapsid antibodies (the standard assay for...
Article
Introduction Panton-Valentine Leukocidin (PVL) producing Staphylococcus aureus is associated with recurrent skin and soft tissue infections and occasionally invasive infections. There is limited evidence to support current public health guidance on decolonisation of cases and household contacts. Methods This systematic review (CRD42020189906) inve...
Article
We describe the impact of changing epidemiology and vaccine introduction on characteristics of COVID-19 outbreaks in 330 long-term care facilities (LTCF) in England between November 2020 and June 2021. As vaccine coverage in LTCF increased and national incidence declined, the total number of outbreaks and outbreak severity decreased across the LTCF...
Preprint
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Background: SARS-CoV-2 vaccines stimulate production of antibodies targeting the spike protein (anti-S). The level of antibodies following vaccination and trajectories of waning may differ between vaccines influencing the level of protection, how soon protection is reduced and, consequently the optimum timing of booster doses. Methods: We measured...
Article
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Background: Differential exposure to public activities may contribute to stark deprivation-related inequalities in SARS-CoV-2 infection and outcomes but has not been directly investigated. We set out to investigate whether participants in Virus Watch-a large community cohort study based in England and Wales-reported differential exposure to public...
Article
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Background: Vaccination intention is key to the success of any vaccination programme, alongside vaccine availability and access. Public intention to take a COVID-19 vaccine is high in England and Wales compared to other countries, but vaccination rate disparities between ethnic, social and age groups has led to concern. Methods: Online survey of...
Preprint
Full-text available
Background Long Term Care Facilities (LTCF) have reported high SARS-CoV-2 infection rates and related mortality, but the proportion infected amongst survivors and duration of the antibody response to natural infection is unknown. We determined the prevalence and stability of nucleocapsid antibodies - the standard assay for detection of prior infect...
Article
We aimed to assess the relative importance of different settings for SARS-CoV-2 transmission in a large community cohort based on perceived location of infection for self-reported confirmed SARS-COV-2 cases. We demonstrate the importance of home, work and education as perceived venues for transmission. In children, education was most important and...
Article
We aimed to assess the relative importance of different settings for SARS-CoV-2 transmission in a large community cohort based on perceived location of infection for self-reported confirmed SARS-COV-2 cases. We demonstrate the importance of home, work and education as perceived venues for transmission. In children, education was most important and...
Article
Introduction: Increased transmissibility of B.1.1.7 variant of concern (VOC) in the UK may explain its rapid emergence and global spread. We analysed data from putative household infector - infectee pairs in the Virus Watch Community cohort study to assess the serial interval of COVID-19 and whether this was affected by emergence of the B.1.1.7 var...
Preprint
Full-text available
Long term care facilities (LTCF) provide residential and/or nursing care support for frail and elderly people and many have suffered from a high prevalence of SARS-CoV-2 infection. Although mortality rates have been high in LTCF residents there is little information regarding the features of SARS-CoV-2-specific immunity after infection in this sett...
Article
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Background Residents of long-term care facilities (LTCFs) have been prioritised for COVID-19 vaccination because of the high COVID-19 mortality in this population. Several countries have implemented an extended interval of up to 12 weeks between the first and second vaccine doses to increase population coverage of single-dose vaccination. We aimed...
Preprint
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Background: Some evidence suggests that individuals may change adherence to public health policies aimed at reducing contact, transmission and spread of the SARS-CoV-2 virus after they receive their first SARS-CoV-2 vaccination. In this study, we aim to estimate the rate of change in average daily travel distance from a participant's registered add...
Preprint
Full-text available
We aimed to assess the relative importance of different settings for SARS-CoV2 transmission in a large community cohort. We demonstrate the importance of home, work and education as venues for transmission. In children, education was most important and in older adults essential shopping was of high importance. Our findings support public health mes...
Preprint
Full-text available
Using data from 4678 children participating in VirusWatch, a UK household cohort study, we estimated the prevalence of persistent symptoms as 1.7%, and 4.6% in children with a history of SARS-CoV-2 infection. Persistent symptoms prevalence was higher in girls, teenagers and children with long-term conditions.
Article
Full-text available
Background SARS-CoV-2 infection represents a major challenge for long-term care facilities (LTCFs) and many residents and staff are seropositive following persistent outbreaks. We aimed to investigate the association between the SARS-CoV-2 antibody status at baseline and subsequent infection in this population. Methods We did a prospective cohort...
Article
Full-text available
Introduction The coronavirus (COVID-19) pandemic has caused significant global mortality and impacted lives around the world. Virus Watch aims to provide evidence on which public health approaches are most likely to be effective in reducing transmission and impact of the virus, and will investigate community incidence, symptom profiles and transmis...
Article
Full-text available
Background The effectiveness of SARS-CoV-2 vaccines in older adults living in long-term care facilities is uncertain. We investigated the protective effect of the first dose of the Oxford-AstraZeneca non-replicating viral-vectored vaccine (ChAdOx1 nCoV-19; AZD1222) and the Pfizer-BioNTech mRNA-based vaccine (BNT162b2) in residents of long-term care...
Preprint
Full-text available
Background: Understanding the symptomatology and accuracy of clinical case definitions for COVID-19 in the community is important for the initiation of Test, Trace and Isolate (TTI) and may, in future, be important for early prescription of antivirals. Methods: Virus Watch is a large community cohort with prospective daily recording of a wide range...
Preprint
Full-text available
Background: Workers differ in their risk of acquiring SARS-CoV-2 infection according to their occupation; however, few studies have been able to control for multiple confounders or investigate the work-related factors that drive differences in occupational risk. Using data from the Virus Watch community cohort study in England and Wales, we set out...
Preprint
Full-text available
Introduction Increased transmissibility of B.1.17 variant of concern (VOC) in the UK may explain its rapid emergence and global spread. We analysed data from putative household infector infectee pairs in the Virus Watch Community cohort study to assess the serial interval of COVID-19 and whether this was affected by emergence of the B.1.17 variant....
Preprint
Full-text available
Background Vaccination constitutes the best long-term solution against Coronavirus Disease 2019 (COVID-19). Real-world immunogenicity data are sparse, particularly for ChAdOx1 and in populations with chronic conditions; and given the extended dosing interval in the UK, it is also important to understand antibody responses in SARS-CoV-2-naive indivi...
Preprint
Full-text available
Background: Household overcrowding is associated with increased risk of infectious diseases across cultures and countries. Limited data exist in England and Wales linking household overcrowding and risk of COVID-19. We used data collected from the Virus Watch cohort to examine the association between overcrowded households and infection to pandemic...
Preprint
Full-text available
Background: Differential exposure to public activities and non-household contacts may contribute to stark deprivation-related inequalities in SARS-CoV-2 infection and outcomes, but has not been directly investigated. We set out to investigate whether participants in Virus Watch - a large community cohort study based in England and Wales - reported...
Article
Background Increased understanding of whether individuals who have recovered from COVID-19 are protected from future SARS-CoV-2 infection is an urgent requirement. We aimed to investigate whether antibodies against SARS-CoV-2 were associated with a decreased risk of symptomatic and asymptomatic reinfection. Methods A large, multicentre, prospectiv...
Preprint
Full-text available
Objectives - To assess trends in intention to accept a COVID-19 vaccine between 1 December 2020 and 25 February 2021, explore associations between socio-demographic factors and vaccination intention and investigate how COVID-19 vaccine- and illness-related attitudes, beliefs and emotions influence vaccination intention. Design - Prospective househo...
Preprint
Full-text available
Background The effectiveness of SARS-CoV-2 vaccines in frail older adults living in Long-Term Care Facilities (LTCFs) is uncertain. We estimated protective effects of the first dose of ChAdOx1 and BNT162b2 vaccines against infection in this population. Methods Cohort study comparing vaccinated and unvaccinated LTCF residents in England, undergoing...
Article
Prospective serosurveillance of severe acute respiratory syndrome coronavirus 2 in 1,069 healthcare workers in London, UK, demonstrated that nucleocapsid antibody titers were stable and sustained for <12 weeks in 312 seropositive participants. This finding was consistent across demographic and clinical variables and contrasts with reports of short-...
Preprint
Full-text available
Background SARS-CoV-2 infection represents a major challenge for Long Term Care Facilities (LTCFs) and many residents and staff are now sero-positive following persistent outbreaks. We investigated the relationship between the presence of SARS-CoV-2 specific antibodies and subsequent infection in this population. Methods Prospective cohort study of...
Article
Full-text available
Background Understanding the T cell response to SARS-CoV-2 is critical to vaccine development, epidemiological surveillance and disease control strategies. This systematic review critically evaluates and synthesises the relevant peer-reviewed and pre-print literature published from 01/01/2020-26/06/2020. Methods For this systematic review, keyword...
Preprint
Full-text available
Background: There is an urgent need to better understand whether individuals who have recovered from COVID-19 are protected from future SARS-CoV-2 infection. Methods: A large multi-centre prospective cohort was recruited from publicly funded hospital staff in the UK. Participants attended regular SARS-CoV-2 PCR and antibody testing (every 2-4 weeks...
Article
Full-text available
Background Progress in characterising the humoral immune response to Severe Acute Respiratory Syndrome 2 (SARS-CoV-2) has been rapid but areas of uncertainty persist. Assessment of the full range of evidence generated to date to understand the characteristics of the antibody response, its dynamics over time, its determinants and the immunity it con...
Preprint
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BACKGROUND The overall risk of reinfection in individuals who have previously had COVID-19 is unknown. To determine if prior SARS-CoV-2 infection (as determined by at least one positive commercial antibody test performed in a laboratory) in healthcare workers confers future immunity to reinfection, we are undertaking a large-scale prospective longi...
Preprint
Full-text available
Introduction The Coronavirus (COVID-19) Pandemic has caused significant global mortality and impacted lives around the world. Virus Watch aims to provide evidence on which public health approaches are most likely to be effective in reducing transmission and impact of the virus, and will investigate community incidence, symptom profiles, and transmi...
Article
Full-text available
Much of routine cancer care has been disrupted due to the perceived susceptibility to SARS-CoV-2 infection in cancer patients. Here, we systematically review the current evidence base pertaining to the prevalence, presentation and outcome of COVID-19 in cancer patients, in order to inform policy and practice going forwards. A keyword-structured sys...
Article
This Web Watch introduces the VaC tracker, a web resource that features an overview of the COVID-19 ‘vaccine landscape’, a clinical trials database and a ‘living review’ that distils the results of vaccine trials as they become available.
Preprint
Full-text available
Introduction Progress in characterising the humoral immune response to Severe Acute Respiratory Syndrome 2 (SARS-CoV-2) has been rapid but areas of uncertainty persist. This review comprehensively evaluated evidence describing the antibody response to SARS-CoV-2 published from 01/01/2020-26/06/2020. Methods Systematic review. Keyword-structured sea...
Preprint
Full-text available
Introduction Understanding the cellular immune response to SARS-CoV-2 is critical to vaccine development, epidemiological surveillance and control strategies. This systematic review critically evaluates and synthesises the relevant peer-reviewed and pre-print literature published in recent months. Methods For this systematic review, independent key...
Article
Full-text available
Point‐of‐care tests (POCTs) offer considerable potential for improving clinical and public health management of COVID‐19 by providing timely information to guide decision‐making, but data on real‐world performance are in short supply. Besides SARS‐CoV‐2‐specific tests, there is growing interest in the role of surrogate (non‐specific) tests such as...
Article
Background Despite an overall national decline in violent crime, weapon carrying and serious violence among youth appears to be rising. Following the example of successful programmes taking a public health approach to violence, such as that in Glasgow (UK), we aimed to review the global evidence base to inform the development of the serious youth v...

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