The role of mask mandates, stay at home orders and school closure in curbing the COVID-19 pandemic prior to vaccination.

BACKGROUND: COVID-19 has quickly spread throughout the world, necessitating assessment of effective containment methods. The purpose of this study was to examine the impact of government mandated school closures, stay at home orders and mask requirements METHODS: Cumulative incidence rates were calculated at 14-day intervals until the day of the first vaccine administration in the country. Rate ratios were calculated using negative binomial regression while investigating the effects of adjusting for several sociodemographic and medical factors RESULTS: Faster implementation of mask mandates was consistently shown to be protective. States with mask mandates made at three to six months had a 1.61 times higher rate than those who implemented within one month (adjusted rate ratio = 1.61, 95% confidence interval: 1.23-2.10, P = .001). States with mask mandates made after 6 months or with no mandate had a 2.16 times higher rate than those who implemented within 1 month (adjusted rate ratio = 2.16, 95% confidence interval: 1.64-2.88, P < .0001). In contrast, both stay at home orders and school closures had no significant influence on disease trajectory. DISCUSSION: The benefits of mask mandates are apparent, especially when mandates were issued within a month. The impact of school closing and stay at home orders were less clear. CONCLUSIONS: Our results suggest that of the different physical distancing measures implemented by the government, mask mandates are the most important.