Although multilayered strategies including preventive behaviors should be adopted to mitigate coronavirus disease 2019 (COVID-19) transmission, evidence on the effectiveness of preventive behaviors against COVID-19 remains limited. This Internet-based prospective cohort study collected baseline data in November 2020 and follow-up data in February 2021, during the third wave of the epidemic in Japan. Among the 19 941 included participants, the percentages reporting that they always used a face mask, practiced hand washing/disinfection, gargling, and ensuring proper room ventilation were 85.4%, 36.0%, 51.1%, and 44.6%, respectively. Multiple logistic regression analyses revealed that less frequently practicing hand washing/disinfection (odds ratio [OR] = 1.20, 95% confidence interval [CI]: 1.10-1.32), gargling (OR = 1.20, 95% CI: 1.10-1.30), and ensuring proper room ventilation (OR = 1.38, 95% CI: 1.26-1.52) were significantly associated with self-reported COVID-19-like illness (CLI). These results suggest that personal preventive behaviors may be effective in reducing CLI, even when universal masking is practiced.
Influence of room ventilation settings on aerosol clearance and distribution
