Covid-19 and Shift Work: A Preliminary Note from the COVISTRESS Online Survey

Previous studies showed an increased risk of COVID-19 in several occupations, particularly healthcare workers. We aimed to explore whether night shift work, a possible determinant of immune suppression, might have contributed to COVID infection in the pre-vaccine months using data from 435 Italian participants (330 women, 105 men) to the COVISTRESS online survey. After adjusting for age, sex, and education, the risk of COVID-19 was elevated among night shift workers (OR = 5.5, 95% CI 2.92, 10.2), particularly among healthcare workers (OR = 8.7, 95% CI 4.07, 18.4). After excluding healthcare workers from the analysis, subjects working night shifts in other jobs also run a 5-fold elevated risk of COVID-19 (OR = 5.1, 95% CI 1.92, 18.4), which was confirmed in a sensitivity analysis excluding subjects who reported working remotely. Parenting school-aged children was also a significant predictor (OR = 2.5; 95% CI 1.20–5.21) of SARS-CoV-2 infection, but there was no interaction with night shift work. Education, marital status, smoking, and sleep quality did not account for the association with night shift work. Our results suggest that, during the 2020 COVID-19 pandemic, night shift workers run an excess risk of COVID-19 infection. Whether this was because of sleep loss-induced suppression of the immune system, confounding, or chance remains to be clarified.