Evaluation of workplace infection prevention and control measures for COVID-19: A prospective cohort study in Japan

Encouraging the implementation of infection prevention and control (IPC) measures has been necessary to prevent workplace infections caused by the coronavirus disease 2019 (COVID-19). However, the effectiveness of these measures in reducing infections has not been thoroughly evaluated. We evaluated employees’ COVID-19 infection rates in relation to the implementation of IPC measures at their workplaces to identify effective workplace measures. This prospective cohort study was conducted between December 2020 and December 2021 using Internet-based self-assessment questionnaires, with 11,982 participants included from the baseline. To estimate whether implementing workplace IPC measures was associated with COVID-19 incidence rates among participants, we estimated multivariate-adjusted relative risk (RR) using a log-binomial model. After adjusting for sex, age, education, household members, occupation-related factors, and personal preventive behaviors, requesting ill employees to refrain from going to work showed significantly lower COVID-19 infection rates than not requesting it (RR: 0.56, 95% CI: 0.34–0.91, p  = 0.019). Employees restricted from reporting to work when ill had significantly lower COVID-19 infection rates than those who did not follow this measure. The results indicated that not coming to work when ill was effective in reducing COVID-19 infections at the workplace. We suggest that companies proactively adopt this policy and encourage their employees to comply with it.