Association of working shifts, inside and outside of healthcare, with severe COVID-19: an observational study

Background Health and key workers have elevated odds of developing severe COVID-19; it is not known, however, if this is exacerbated in those with irregular work patterns. We aimed to investigate the odds of developing severe COVID-19 in health and shift workers. Methods We included UK Biobank participants in employment or self-employed at baseline (2006-2010) and with linked COVID-19 data to 31st August 2020. Participants were grouped as neither a health worker nor shift worker (reference category) at baseline, health worker only, shift worker only, or both, and associations with severe COVID-19 investigated in logistic regressions. Results Of 235,685 participants (81 center dot 5% neither health nor shift worker, 1 center dot 4% health worker only, 16 center dot 9% shift worker only, and 0 center dot 3% both), there were 580 (0 center dot 25%) cases of severe COVID-19. The odds of severe COVID-19 was higher in health workers (adjusted odds ratio: 2 center dot 32 [95% CI: 1 center dot 33, 4 center dot 05]; shift workers (2 center dot 06 [1 center dot 72, 2 center dot 47]); and in health workers who worked shifts (7 center dot 56 [3 center dot 86, 14 center dot 79]). Being both a health worker and a shift worker had a possible greater impact on the odds of severe COVID-19 in South Asian and Black and African Caribbean ethnicities compared to White individuals. Conclusions Both health and shift work (measured at baseline, 2006-2010) were independently associated with over twice the odds of severe COVID-19 in 2020; the odds were over seven times higher in health workers who work shifts. Vaccinations, therapeutic and preventative options should take into consideration not only health and key worker status but also shift worker status.