Hospital staff who regularly work night shifts have a 20 per cent higher risk of flu-like and respiratory complaints than staff who only work day shifts. This is shown by a RIVM National Institute for Public Health and the Environment study among almost 600 employees of six Dutch hospitals. An article about this research was recently published in the American Journal of Epidemiology.

More than 500 hospital staff (mainly nurses but also doctors, caregivers and paramedics) who regularly work night shifts and nearly one hundred day workers participated in the study. During the influenza season, everybody was asked to keep track of their flu-like or respiratory complaints for six months using a specially developed smartphone app. The app then identified episodes of such complaints. An episode was defined as having at least one day of/with? two or more different flu-like illness or respiratory symptoms, or at least one of those complaints during two days, such as nasal cold, cough or fever. The study showed that people who worked at night experienced an average of 3 to 4 episodes of flu- and respiratory complaints during the winter season. Among the hospital staff who worked only during the day, that number was between 2 and 3 episodes. However, the average duration of the episodes was not different.

In addition, it appeared that night shift workers also reported more episodes with serious complaints than day workers. This research shows that for night shift workers, in addition to the already known risks, a higher susceptibility to respiratory infections is also present. This has direct consequences for the health of night shift workers, but possibly also indirect consequences for patients, such as a higher risk of infection. Follow-up research should provide insight into possible causality and underlying mechanisms connecting night shift work and infection susceptibility. The research is part of a larger RIVM project into night shift work and health, which also focuses on mechanisms that connect night shift work with health, such as diet, sleep and physical activity. Amsterdam University Medical Center (Amsterdam UMC)  and University Medical Center Utrecht (UMC Utrecht) also contributed to this research.