Occupation, Work-Related Contact, and SARS-CoV-2 Anti-Nucleocapsid Serological Status: Findings from the Virus Watch prospective cohort study

Abstract

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 to estimate the total effect of occupation on SARS-CoV-2 serological status, whether this is mediated by frequency of close contact within the workplace, and how exposure to poorly ventilated workplaces varied across occupations. Methods: We used data from a sub-cohort (n =3761) of adults (≥18) tested for SARS-CoV-2 anti-nucleocapsid antibodies between 01 February-28 April 2021 and responded to a questionnaire about work during the pandemic. Anti-nucleocapsid antibodies were used as a proxy of prior natural infection with COVID-19. We used logistic decomposition to estimate the total and direct effect of occupation and indirect effect of workplace contact frequency on odds of seropositivity, adjusting for age, sex, household income and region. We investigated the relationship between occupation and exposure to poorly-ventilated workplace environments using ordinal logistic regression. Results: Seropositivity was 16.0% (113/707) amongst workers with daily close contact, compared to 12.9% (120/933) for those with intermediate-frequency contact and 9.6% (203/2121) for those with no work-related close contact. Healthcare (OR= 2.14, 95% CI 1.47,3.12), indoor trade, process and plant (2.09, 1.31,3.33), leisure and personal service (1.96, 1.004,3.84), and transport and mobile machine (2.17, 1.12,4.18) workers had elevated total odds of SARS-CoV-2 seropositivity compared to other professional and associate occupations. Frequency of workplace contact accounted for a variable part of the increased odds in different occupational groups (OR range 1.04 [1.0004,1.07] - 1.22 [1.07, 1.38]). Healthcare workers and indoor trades and process plant workers continued to have raised odds of infection after accounting for work-related contact, and also had had greater odds of frequent exposure to poorly-ventilated workplaces (respectively 2.15 [1.66, 2.79] and (1.51, [1.12, 2.04]). Discussion: Marked variations in occupational odds of seropositivity remain after accounting for age, sex, region, and household income. Close contact in the workplace appears to contribute substantially to this variation. Reducing frequency of workplace contact is a critical part of COVID-19 control measures.

Validation of a COVID-19 Job Exposure Matrix (COVID-19-JEM) for Occupational Risk of a SARS-CoV-2 Infection at Work: Using Data of Dutch Workers

“…The results showed indeed that higher-risk scores attributed by the COVID-19-JEM were associated with a higher incidence of self-reported COVID-19, except for the dimensions on precarious work. This observed association is in line with other studies investigating associations between topics similar to the transmission and mitigation factors of the COVID-19-JEM and COVID-19 or other respiratory diseases ( Jefferson et al , 2008 ; Kampf et al , 2020 ; Vokó and Pitter, 2020 ; Backer et al , 2021 ; Beale et al , 2022 ; Li and Tang, 2021 ). These findings indicate that the COVID-19-JEM is a useful tool for assessing the risk of having had COVID-19 when data on exposure at individual level are lacking.…”

“…Moreover, we need to be aware that only one third of the infected study population thought they were infected at the worksite. Even though this is a substantial proportion which is in line with what others have reported ( Lan et al , 2020 ; Beale et al , 2022 ), it also means that it is not the only key setting of being infected with SARS-CoV-2.…”

“…In many countries, these strategies are incorporated in measures, affecting the entire population. The workplace is one of the key settings in the spread of COVID-19 and plays a role in COVID-19 caused mortality ( Baker et al , 2020 ; Lan et al , 2020 ; Marinaccio et al , 2020a ; Beale et al , 2022 ; Nafilyan et al , 2021 ). To minimize social interactions, and thereby reduce infection rates, governments encouraged workers to work from home as much as possible, and restricted opening hours of other sectors several times during the pandemic, although responses varied between countries and stages of the pandemic.…”

“…Outbreaks have also been described in industries with a high prevalence of precarious workers, such as agriculture and meat processing ( Dyal, 2020 ; Fassani and Mazza, 2020 ). In England and Wales, workers with an elevated risk of infection were healthcare workers, indoor trade workers, process and plant workers, leisure and personal service workers, transport workers and workers working with mobile machines ( Beale et al , 2022 ). This elevated risk was substantially accounted for by the frequency of contacts at the workplace.…”

Occupational differences in SARS-CoV-2 infection: Analysis of the UK ONS Coronavirus (COVID-19) Infection Survey

“…Several studies have found increased risks of infection and mortality from COVID-19 amongst healthcare workers (5)(6)(7)(8) and those working in public facing transport occupations when compared to non-essential or other workers. Other studies have not found an increased risk (9) or suggest it varies by type of worker and/or stage of the pandemic (10)(11)(12)(13)(14)(15)(16).…”