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Key FeaturesVirus Watch is a national community cohort study of COVID-19 in households in England and Wales, established in June 2020. The study aims to provide evidence on which public health approaches are most effective in reducing transmission, and investigate community incidence, symptoms, and transmission of COVID-19 in relation to population movement and behaviours.28,527 households and 58,628 participants of age (0-98 years, mean age 48), were recruited between June 2020 - July 2022Data collected include demographics, details on occupation, co-morbidities, medications, and infection-prevention behaviours. Households are followed up weekly with illness surveys capturing symptoms and their severity, activities in the week prior to symptom onset and any COVID-19 test results. Monthly surveys capture household finance, employment, mental health, access to healthcare, vaccination uptake, activities and contacts. Data have been linked to Hospital Episode Statistics (HES), inpatient and critical care episodes, outpatient visits, emergency care contacts, mortality, virology testing and vaccination data held by NHS Digital.Nested within Virus Watch are a serology & PCR cohort study (n=12,877) and a vaccine evaluation study (n=19,555).Study data are deposited in the Office of National Statistics (ONS) Secure Research Service (SRS). Survey data are available under restricted access upon request to ONS SRS.

BackgroundDifferential 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 different levels of exposure to public activities and non-household contacts during the Autumn-Winter phase of the COVID-19 pandemic according to postcode-level socioeconomic deprivation.MethodsParticipants (n=20120-25228 across surveys) reported their daily activities during three weekly periods in late November 2020, late December 2020, and mid-February 2021. Deprivation was quantified based on participants’ postcode of residence using English or Welsh Indices of Multiple Deprivation quintiles. We used Poisson mixed effect models with robust standard errors to estimate the relationship between deprivation and risk of exposure to public activities during each survey period.ResultsRelative to participants in the least deprived areas, participants in the most deprived areas persistently exhibited elevated risk of exposure to vehicle sharing (aRR range across time points 1.73-8.52), public transport (aRR 3.13-5.73), work or education outside of the household (aRR 1.09-1.21), essential shops (aRR 1.09-1.13) and non-household contacts (aRR 1.15-1.19) across multiple survey periods.ConclusionDifferential exposure to essential public activities in deprived communities is likely to contribute to inequalities in infection risk and outcomes during the COVID-19 pandemic. Public health interventions to reduce exposure during essential activities and financial and practical support to enable low-paid workers to stay at home during periods of intense transmission may reduce COVID-related inequalities.

Background SARS-CoV-2 infection in Healthcare Workers (HCWs) is a public health concern during the pandemic. Little description has been made of their antibody response over time in the presence or absence detectable SARS-CoV-2 RNA and of symptoms. We followed a cohort of patient-facing HCWs at an acute hospital in London to measure seroconversion and RNA detection at the peak of the pandemic in London. Methods We enrolled 200 front-line HCWs between 26 March and 8 April 2020 and collected twice-weekly self-administered nose and throat swabs and monthly blood samples. Baseline and regular symptom data were also collected. Swabs were tested for SARS-CoV-2 RNA by polymerase chain reaction, and serum for IgM, IgA and IgG antibodies to the virus spike protein by enzyme-linked immunosorbent assay and flow cytometry. Findings We enrolled HCWs with a variety of roles who worked in areas where COVID-19 patients were admitted and cared for. During the first month of observation, 42/200 (21%) HCWs were PCR positive in at least one nose and throat swab. Only 8/42 HCW (19%) who were PCR positive during the study period had symptoms that met the current case definition. Of 181 HCWs who provided enrollment and follow-up blood samples, 82/181 (45.3%) were seropositive; 36/181 (19.9%) seroconverted during the study and 46/181 (25.4%) were seropositive at both time points. In 33 HCWs who had positive serology at baseline but were PCR negative, 32 remained PCR negative throughout follow-up. One HCW had a PCR positive swab six days after enrollment, likely representing a waning infection. Interpretation The extremely high seropositivity and RNA detection in this cohort of front-line HCWs who worked during the peak of the pandemic brings policies to protect staff and patients in the hospital environment into acute focus. Our findings have implications for planning for the expected second wave and for future vaccination roll out campaigns in similar settings. The further evidence of asymptomatic SARS-CoV-2 infection indicates that asymptomatic surveillance of HCWs is essential while our study sets the foundations to answer pertinent questions around the duration of protective immune response and the risk of re-infection.