Shift work is associated with positive COVID-19 status in hospitalised patients

Introduction Shift work is associated with both mental, and physical ill health, including lung disease and infections. However, the impact of shift work on significant COVID-19 illness has not be assessed. We therefore investigated whether shift work is associated with COVID-19. Methods 501,000 UK biobank participants were linked to secondary care SARS-CoV-2 PCR results from public health England. Healthcare workers and those without an occupational history were excluded from analysis. Results Multivariate logistic regression taking into account age, sex, ethnicity and deprivation index revealed that irregular shift work (OR 2.42 95%CI 1.92-3.05), permanent shift work (OR 2.5, 95%CI 1.95-3.19), day shift work (OR 2.01, 95%CI 1.55-2.6), irregular night shift work (OR 3.04, 95%CI 2.37-3.9) and permanent night shift work (OR 2.49, 95%CI 1.67-3.7) were all associated with positive COVID-19 tests compared to participants that did not perform shift work. This relationship persisted after adding sleep duration, chronotype, pre-morbid disease, BMI, alcohol and smoking. Work factors (proximity to a colleague combined with estimated disease exposure) were positively correlated with COVID-19 incidence (r 2 =0.248, p=0.02). If this was added to the model shift work frequency remained significantly associated with COVID-19. To control for non-measured occupational factors the incidence of COVID-19 in shift workers was compared to colleagues in the same job who did not do shift work. Shift workers had a higher incidence of COVID-19 (p<0.01). Conclusions Shift work is associated with a higher likelihood of in-hospital COVID-19 positivity. This risk could potentially be mitigated via additional workplace precautions or vaccination.