Occupational risk of SARS-CoV-2 infection: a nationwide register-based study of the Danish workforce during the Covid-19 pandemic 2020-21

ObjectivesMost earlier studies on occupational risk of Covid-19 covering the entire workforce are based on relatively rare outcomes such as hospital admission and mortality. This study examines the incidence of SARS-CoV-2 infection by occupational group based upon real-time polymerase chain reaction tests (RT-PCR). MethodsThe cohort includes 2.4 million Danish employees, 20-69 years of age. All data were retrieved from public registries. The sex-specific incidence rate ratios (IRR) of first-occurring positive RT-PCR test from week 8 of 2020 through week 50 of 2021 were computed by Poisson regression for each 4-digit DISCO-08 job code with more than 100 employees (337 in men; 297 in women). Occupational groups with low risk of workplace infection according to a job exposure matrix constituted the reference group. Risk estimates were adjusted by demographic, social and health characteristics including household size, completed Covid-19 vaccination, pandemic wave and occupation-specific frequency of testing. ResultsIRRs of SARS-CoV-2 infection were elevated in 34 occupations comprising 12 % of male employees and 45 occupations comprising 41 % of female employees. All IRR estimates were below 2.0. Decreased IRRs were observed in 85 occupations in men but none in women. DiscussionWe observed a modestly increased risk of SARS-CoV-2 infection among employees in numerous occupations indicating a large potential for preventive actions, especially in the female workforce. Cautious interpretation of observed risk in specific occupations is needed because of methodological issues inherent in analyses of RT-PCR-test results and because of multiple statistical tests. WHAT IS ALREADY KNOW ABOUT THIS TOPIC?O_LIEpidemiological studies suggest that the workplace contribute to the Covid-19 pandemic C_LIO_LIResults are mostly based upon studies of less frequent outcomes as Covid-19 morbidity or mortality which limits inference about risk in specific occupations C_LI WHAT THIS STUDY ADDSO_LIThe risk of Covid-19 infection was increased in 34 of 337 occupations in men and in 45 of 297 occupations in women C_LIO_LISome 12% of the Danish male workforce and 41% of the female workforce are at increased risk of Covid-19 infection C_LI HOW THIS RESEARCH MIGHT AFFECT RESEARCH, PRACTICE OR POLICY?O_LIPreventive actions targeting the workplace may contribute substantially to alleviate disease occurrence in the ongoing Covid-19 and similar future pandemics. C_LI