The Impact of State Mask-Wearing Requirements on the Growth of COVID-19 Cases, Hospitalizations, and Deaths in the United States

Abstract

In ecologic analyses of US states, piecewise multivariable models showed lower post- vs. pre-mask requirement case-rate slopes, with -1.0% (95%CI: -1.34%, -0.57%) and -0.44% (95%CI: -0.86%, -0.03%) per 100,000 per day among early- and late- versus never-adopter states, respectively. Our findings support statewide mask requirements to mitigate COVID-19 transmission.