Are night shift workers at an increased risk for COVID-19?

Abstract

Recent data has revealed an association between coronavirus disease-19 (COVID-19) incidence and seasonally regulated androgen sensitivity. This potential relationship between SARS-CoV-2 infection and clock genes, coupled with previously reported effects of night shift work on health, leads us to hypothesize that night shift workers may be at an increased physiological risk of coronavirus disease-19 (COVID-19). Shift work, especially night shift work, has long been associated with several chronic health conditions. The mechanisms that drive these associations are not well understood; however, current literature suggests that the disruption of circadian rhythms may cause downstream hormonal and immune effects that render night shift workers more susceptible to disease. First, circadian rhythms may play a role in the mechanism of viral infection, as viral vaccines administered in the morning elicit greater immune responses than those administered in the afternoon. Next, increased exposure to light at night may inhibit the production of melatonin, which has been observed to enhance DNA repair and shown to upregulate expression of Bmal1 , an established inhibitor of herpes simplex virus and influenza. Finally, abnormal immune cell and cytokine levels have been observed following night-shift work. These data suggest that further research is warranted and that high-risk occupations should be taken into consideration as public health policies are introduced and evolve.

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

“…Alongside other risk factors (e.g. health-related behaviours [ 15 ], psychological stress and genetic predisposition), this may be associated with a ‘cytokine storm’ [ 22 , 29 , 30 ] contributing to the increased odds of severe COVID-19 we observed in shift-workers.…”

“…Shift workers are more likely to have disturbed sleep and variable sleep patterns [ 21 ] leading to disruption of the circadian rhythm. This has been hypothesised to increase the odds of COVID-19 in night shift workers [ 22 ], but is evident even if the shift pattern does not include night work, likely due to sleep disruption in relation to circadian rhythms [ 21 ], which may persist in the years following cessation of shift work [ 23 ]. Recent data have suggested that sleep disruption and high variability in sleep timing are associated with the odds of testing positive for COVID-19 and development of severe infection [ 15 ].…”

Developing a Flexible National Wastewater Surveillance System for COVID-19 and Beyond

“…For COVID-19, collecting samples in the morning (when most people routinely use the bathroom) may help capture a larger viral load. However, some suggest that larger flows in the morning could result in a more diluted signal ( WRF 2020 ), and morning sampling might also overlook certain underrepresented populations, such as shift workers, who may be more susceptible to COVID-19 and exacerbating chronic conditions ( Lim et al. 2020 ).…”

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

“…Alongside other risk factors (e.g. lifestyle factors, psychological stress and genetic predisposition), this may be associated with a ‘cytokine storm’ 22,28,29 contributing to the increased risk of severe COVID-19 we observed in shift-workers.…”