The HPRU in Environmental Exposures and Health is contributing to the global research effort to tackle the COVID-19 pandemic. Below is a list of current and planned Covid-19 research studies and other activities by HPRU teams.

The REACT programme is a large-scale assessment of COVID-19 home testing, to evaluate different testing assays and inform the future deployment of self-testing, and to provide estimate levels of SARS-CoV-2 infection in the population (including asymptomatic cases). The programme comprises two main arms:
- REACT 1: a rapid, large-scale study of SARS-CoV-2 antigen prevalence in England, involving the collection and analysis of swab samples for a large sample of the population (100,000 randomly selected people from 315 local authorities across England) to identify rates of active SARS-CoV-2 infection.
- REACT 2: is the largest COVID-19 surveillance study undertaken in England examining the prevalence of SARS-CoV-2 antibodies in the community. It consists of a series of studies evaluating the accuracy, usability and acceptability of different home-use, self-administered Lateral Flow Tests (LFTs) to detect COVID-19 antibodies and prior infection, together with a large-scale study (up to 200,000 randomly selected members of the public in England) to quantify the cumulative community seroprevalence since the beginning of the SARS-CoV-2 epidemic and characterise geographical and socioeconomic variations.

• Flower B, Brown JC, Simmons B, et al. for the REACT Study group. Clinical and laboratory evaluation of SARS-CoV-2 lateral flow assays for use in a national COVID-19 seroprevalence survey. Thorax. 2020 Dec;75(12):1082-1088. doi: 10.1136/thoraxjnl-2020-215732. Epub 2020 Aug 12. PMID: 32796119.
• Graham NSN, Junghans C, Downes R, et al. for the REACT Study group. SARS-CoV-2 infection, clinical features and outcome of COVID-19 in United Kingdom nursing homes. J Infect. 2020 Sep;81(3):411-419. doi: 10.1016/j.jinf.2020.05.073. Epub 2020 Jun 3. PMID: 32504743.
• Atchison C, Pristerà P, Cooper E, et al. for the REACT Study group. Usability and acceptability of home-based self-testing for SARS-CoV-2 antibodies for population surveillance. Clin Infect Dis. 2021 May 4;72(9):e384-e393. doi: 10.1093/cid/ciaa1178. PMID: 32785665.
• Ward H, Atchison CJ, Whitaker M, et al. for the REACT Study group. Antibody prevalence for SARS-CoV-2 in England following first peak of the pandemic: REACT2 study in 100,000 adults. Nat Commun. 2021 Feb 10;12(1):905. doi: 10.1038/s41467-021-21237-w. PMID: 33568663.
• Moshe M, Daunt A, Flower B, et al. For the React Study group. SARS-CoV-2 lateral flow assays for possible use in national covid-19 seroprevalence surveys (React 2): diagnostic accuracy study. BMJ. 2021 Mar 2;372:n423. doi: 10.1136/bmj.n423. PMID: 33653694.
• Riley S, Atchison C, Ashby D, et al. for the REACT Study group. REal-time Assessment of Community Transmission (REACT) of SARS-CoV-2 virus: Study protocol. Wellcome Open Res. 2021 Apr 21;5:200. doi: 10.12688/wellcomeopenres.16228.2. PMID: 33997297.

• Riley S, Ainslie KEC, Eales O, et al. for the REACT Study group. Transient dynamics of SARS-CoV-2 as England exited national lockdown. [Preprint] medRxiv - doi: 10.1101/2020.08.05.20169078
• Riley S, Ainslie KEC, Eales O, et al. for the REACT Study group. Community prevalence of SARS-CoV-2 virus in England during May 2020: REACT study. [Preprint] medRxiv - doi:10.1101/2020.07.10.20150524
• Riley S, Ainslie KEC, Eales O, et al. for the REACT study group. Resurgence of SARS-CoV-2 in England: detection by community antigen surveillance. [Preprint] medRxiv 2020.09.11.20192492; doi:
• Ward H, Cooke G, Atchison C, et al. for the REACT Study group. Declining prevalence of antibody positivity to SARS-CoV-2: a community study of 365,000 adults. [Preprint] medRxiv 2020.10.26.20219725; doi:
• Riley S, Ainslie KEC, Eales O, et al. for the REACT Study group. High prevalence of SARS-CoV-2 swab positivity in England during September 2020: interim report of round 5 of REACT-1 study. [Preprint] medRxiv 2020.09.30.20204727; doi:
• Riley S, Ainslie KEC, Eales O, et al. for the REACT Study group. High and increasing prevalence of SARS-CoV-2 swab positivity in England during end September beginning October 2020: REACT-1 round 5 updated report. [Preprint] medRxiv 2020.10.12.20211227; doi:
• Riley S, Ainslie KEC, Eales O, et al. for the REACT Study group. High prevalence of SARS-CoV-2 swab positivity and increasing R number in England during October 2020: REACT-1 round 6 interim report. [Preprint] medRxiv 2020.10.30.20223123; doi:
• Riley S, Ainslie KEC, Eales O, et al. for the REACT Study group. REACT-1 round 6 updated report: high prevalence of SARS-CoV-2 swab positivity with reduced rate of growth in England at the start of November 2020. [Preprint] medRxiv 2020.11.18.20233932; doi:
• Riley S, Eales O, Walters CE, et al. for the REACT Study group. REACT-1 round 7 interim report: fall in prevalence of swab-positivity in England during national lockdown. [Preprint] medRxiv 2020.11.30.20239806; doi:
• Riley S, Walters CE, Wang H, et al. for the REACT Study group. REACT-1 round 7 updated report: regional heterogeneity in changes in prevalence of SARS-CoV-2 infection during the second national COVID-19 lockdown in England. [Preprint] medRxiv 2020.12.15.20248244; doi:
• Riley S, Wang H, Eales O, et al. for the REACT Study group. REACT-1 round 8 interim report: SARS-CoV-2 prevalence during the initial stages of the third national lockdown in England. [Preprint] medRxiv 2021.01.20.21250158; doi:
• Riley S, Eales O, Walters CE, et al. for the REACT Study group. REACT-1 round 8 final report: high average prevalence with regional heterogeneity of trends in SARS-CoV-2 infection in the community in England during January 2021. [Preprint] medRxiv 2021.01.28.21250606; doi:
• Riley S, Walters CE, Wang H, et al. for the REACT Study group. REACT-1 round 9 interim report: downward trend of SARS-CoV-2 in England in February 2021 but still at high prevalence. [Preprint] medRxiv 2021.02.18.21251973; doi:
• Ward H, Cooke G, Whitaker M, et al. for the REACT Study group. REACT-2 Round 5: increasing prevalence of SARS-CoV-2 antibodies demonstrate impact of the second wave and of vaccine roll-out in England. [Preprint] medRxiv 2021.02.26.21252512; doi:
• Riley S, Wang H, Eales O, et al. for the REACT Study group. REACT-1 round 9 final report: Continued but slowing decline of prevalence of SARS-CoV-2 during national lockdown in England in February 2021. [Preprint] medRxiv 2021.03.03.21252856; doi:
• Riley S, Eales O, Haw D, et al. for the REACT Study group. REACT-1 round 10 report: Level prevalence of SARS-CoV-2 swab-positivity in England during third national lockdown in March 2021. [Preprint] medRxiv 2021.04.08.21255100; doi:
• Riley S, Haw D, Walters CE, et al. for the REACT Study group. REACT-1 round 11 report: low prevalence of SARS-CoV-2 infection in the community prior to the third step of the English roadmap out of lockdown. [Preprint] medRxiv 2021.05.13.21257144; doi:
This study aims to address some of the major gaps in our understanding of SARS-CoV-2 infection and disease, in particular with respect to differences in disease susceptibility, severity of infection and disease mechanisms. We will apply a multi-omics approach - encompassing whole genome sequencing, proteomic, transcriptomic and metabolomic analyses - to mild/asymptomatic cases, to identify biological pathways that are protective of or deleterious to the response to SARS-CoV-2 infection. In a partnership between the DHSC-funded GenOMICC programme (led by Genomics England) and the REACT programme, we propose to recruit c.8000 mild/asymptomatic REACT participants for which we will obtain a multi-omic profile to sit alongside the whole genome sequencing already funded, creating an unparalleled resource for identifying novel targets for disease prevention or drug discovery.
The REACT-Long COVID (REACT-LC) programme aims to characterise the genetic, biological, social and environmental signatures and pathways that underpin progression to Long COVID, and to understand the natural history and long-term sequelae post-SARS-CoV-2 infection, to inform new approaches to diagnosis, treatment and support. This study will involve 120,000 people in the community who have taken part in the REACT study - over 30,000 that have had positive test results, plus a sample of 90,000 who tested negative. Participants will be sent regular surveys about their health, symptoms and experiences since the test, and a subset of 8,000 participants with positive tests, including at least 4,000 with Long COVID, will undergo detailed clinical phenotyping and provide samples for multi-omic analyses to identify genetic and other biological markers.
Siemens Healthineers markets a range of tests supporting the diagnosis and management of COVID-19. This industrial partner is interested in collaborating with the REACT team to assess the performance of its antibody tests and to evaluate the extent to which unsupervised subjects can self-collect samples to support testing.
The CO-CONNECT project brings together 29 different UK organisations to create a single information resource linking 44 cohort, serology and other health and non-health data sources on SARS-CoV-2 in the UK. This project addresses a major data engineering challenge, enabled by Health Data Research (HDR) UK, to create a ‘one-stop’ resource that will catalyse trustworthy, multi-stakeholder utilisation of curated COVID-19 data for public, private and third sector benefit.
This project aims to characterise and quantify the biological, social and environmental drivers of medium-term health outcomes following infection with SARS-CoV-2, through linkage of national primary and secondary healthcare data to the REACT national community prevalence programme, and further enhance this cohort through the addition of contextual geo-referenced environmental data.
This project, funded by a philanthropic donation form the Huo Family Foundation, includes a series of studies on the etiology of SARS-CoV-2 infection and on testing and surveillance technologies, to help identify at-risk populations and inform infection control measures. It includes research on: establishment and linkage of COVID-19 research databases; analyses of multi-omic signatures of individuals that have tested positive for SARS-CoV-2 in the REACT community programme to further our understanding the biology underpinning SARS-CoV-2 infection; evaluating the implementation of asymptomatic testing and follow-up contact tracing/ isolation; testing the accuracy and usability of COVID-19 diagnostic tests not included within the scope of the government-funded REACT-1 study.
Analysis of UK Biobank data identifying risk factors for testing positive or negative for SARS-CoV-2 infection up to 18 May 2020, as well as those discriminating test positive vs test negative individuals using a test negative design approach.

• Chadeau-Hyam M, Bodinier B, Elliott J, et al. Risk factors for positive and negative COVID-19 tests: a cautious and in-depth analysis of UK biobank data. Int J Epidemiol. 2020 Oct 1;49(5):1454-1467. DOI: 10.1093/ije/dyaa134; PMID: 32814959.
• Elliott J, Bodinier B, Whittaker M, et al. COVID-19 mortality in the UK Biobank cohort: revisiting and evaluating risk factors. Eur. J. Epidemiol. 2021 36(3), pp. 299-309. DOI: 10.1007/s10654-021-00722-y; PMID: 33587202
This study will investigate the impacts of the COVID-19 pandemic and public health measures on adolescent mental health and wellbeing, amongt a large adolescent cohort SCAMP (Study of Cognition Adolescents and Mobile Phones). This research will investigate questions such as:
- risk factors for mental health problems due to COVID-19 public health measures and their profound disruption to adolescent education and social networks and find out what factors can be changed to boost resilience;
- whether changes in use of digital technology have a positive or negative impact on adolescent mental health;
- who is most at-risk of negative outcomes, such as those experiencing more family stress, lack of access to healthy food and outdoor/green space.
Study evaluating the impact of the COVID-19 pandemic on non-COVID-19 morbidity and mortality including impacts of health inequalities. We used over 10 years of national level routine health data, at high spatial and temporal resolution, to dynamically track how trends are deviating from the expected patterns during the pandemic. Impacts on health inequalities were identified and findings will inform health policy and resource allocation decisions at local and national level.

Davies B, Parkes BL, Bennett J, et al. Community factors and excess mortality in first wave of the COVID-19 pandemic. medRxiv 2020.11.19.20234849; doi:
This study within the CHILL cohort aims to examine the impact of Sars-Cov-2 infection / air pollution changes (both policy and lockdown driven) on the cognitive development of children. We trialled cognitive testing in tis cohort last year and the proposal will expand on this work and establish more formal links with the Born in Bradford group, whose methodology is used.

• Colligan G, Tsocheva I, Scales J, et al. Investigating the impact of London’s Ultra Low Emission Zone on children’s health: Children’s Health in London and Luton (CHILL): Protocol for a prospective parallel cohort study. medRxiv 2021.02.04.21251049; doi:
High time resolution aerosol size distribution measurements in an ICU ward at Medway Hospital in association with Dr Rahuldeb Sarkar, Consultant in Respiratory Medicine & Critical Care Medway NHS Foundation Trust.
- Measuring aerosol generation from patient under different ventilation methodologies and different procedures
- Aim to assess aerosol exposure of staff working in close proximity to COVID patients
- Paper describing early results submitted to the British Journal of Anaesthesia.
The change in emissions associated with the pandemic provides a ‘real world’ opportunity to assess emission reduction impacts on population exposure and atmospheric chemistry at a time when there is concerted policy effort to reduce the UK’s air pollution health burden. Defra’s Air Quality Evidence Group issued a call for evidence and ERG members are undertaking analyses to inform this and prepare potential future funding applications:
- Spatial and temporal analysis of LAQN monitoring sites to establish changes in concentration between pre lockdown and lockdown periods; including accounting for the effects of changes to meteorology and dispersion to estimate emission changes.
- Estimation of the changes to the toxic mixture of air pollutants, and in particular the combined toxicity of different pollutants.
- Quantifying changes to personal exposure of people in London, indoors and outdoors, including school children, professional drivers, medics and tube users.
- This is also an ideal opportunity to study the air pollution impacts of a world working towards 'net-zero' CO2 emissions, improving our understanding of model uncertainties and the reliability of policy analysis and air pollution predictions for net zero scenarios.
- Initial analysis undertaken and reported to Defra’s Air Quality Expert Group. More detailed analytical project in planning.
The Covid-19 lockdown is the largest ‘natural experiment’ of global emissions reductions of a generation. The aim of this study is to assess the change in personal exposure of the whole London population to PM2.5 and NO2 brought about by both the change in indoor, in-vehicle and outdoor concentrations, as a consequence of the Covid-19 lockdown, and due to behaviour change such as spending more time at home and changing mode of transport. London has a diverse population so we will undertake this analysis for different population subgroups, by age, focusing on the vulnerable such as the over 70s, gender and ethnicity (e.g. BAME). We will assess the health impacts of past long-term exposures, changes in exposure during the pandemic interventions and their interactions with Covid-19 transmission and mortality.
The impact of the COVID-19 has disproportionately affected those with pre-existing disease, including those with diabetes, the obese, as well as old people, males and Black and Asian ethnic groups. Air pollution has been cited as a potential additional risk factor for COVID-19 disease. This study aims to significantly improve our understanding of the exposure to air pollution indoors and outdoors, of different vulnerable sub-populations in London during the COVID-19 lockdown. We will use the novel NERC-funded London Hybrid Exposure Model (LHEM) which is unique in the UK, and in analysis for Defra's Air Quality Expert Group has already given some important insights into the potential exposures during the COVID-19 lockdown period. During the COVID-19 lockdown and subsequent easing of the restrictions, we will assess the change in personal exposure of all Londoners to PM2.5, NO2 and O3, split by age, gender, ethnicity, socioeconomic status, and by occupation, such as professional drivers, tube users, medical staff and children. Improving our understanding of the sources of exposure will lead to policy advice on exposure reduction and provide a unique exposure dataset that will allow epidemiologists to better assess whether air pollution is a risk factor for COVID-19.
Though air pollution is a problem faced by everybody, research has shown that those living in neighbourhoods of low social economic status are more likely to be exposed to higher air pollution levels. In addition, those with underlying health conditions, including diabetes, heart and lung disease are more susceptible to its health effects. This equity gap has recently become more apparent with the COVID-19 pandemic, as air pollution has been linked to poor health outcomes of COVID-19, with a disproportionately high impact within the Black, Asian and Minority Ethnic (BAME) population. The reasons for this are not yet known but are likely to relate to existing vulnerabilities including health complications, low social economic status, absence of choice and awareness. This study’s aim is to investigate vulnerable and minority ethnic groups’ perceptions of the relationship between air pollution and health and how this relationship has been impacted by the coronavirus (COVID-19) crisis.
MAP-C19 will aim to explore the impact of atmospheric conditions on COVID in the UK, by bringing together experts responsible for the London Air Quality Network which has collected detailed data about atmospheric environmental hazards in the captial, with experts in COVID surveillance from the English Sentinel Surveillance network run by the Oxford- RCGP RSC. Together we will look to map COVID-19 occurrence rates against data from the London Air Quality Network. We will use these examples together with other data collected nationally, to understand how atmospheric conditions could affect COVID in other cities including Liverpool Manchester, Bristol, Leeds, Birmingham, Newcastle, Cardiff, Glasgow, Edinburgh and what mitigation measures may be put in place.
The aim of this project is to measure SARS-CoV-2 and pharmaceuticals in urban wastewater using mass spectrometry, to accurately monitor large population activity in near-real time. The methods developed will be applied to pre-pandemic urban wastewater samples for pharmaceuticals (collected in Dec 2019).
Via COMEAP, involved in commenting on papers on air pollution and COVID19 published by others. Via COMEAP, in discussions with PHE and ONS on possible links between air pollution and Covid-19; ONS report published in early August.