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 (r2=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.