Effects of mask mandates, opening restaurants on COVID-19 cases, mortality

Editor's Note

The Centers for Disease Control and Prevention (CDC) on March 5 released a study showing mask mandates were responsible for a decrease in COVID-19 case growth rates by 0.5% after 20 days and by 1.8% after 100 days.

Mask mandates also were associated with a 0.7% decrease in mortality rates at 20 days and a 1.9% decrease after 100 days.

Daily case and mortality growth rates before implementation of mask mandates were not statistically different from the reference period.

During the same period, states allowed restaurants to reopen for on-premises dining in 97.9% of US counties. Changes in COVID-19 case and mortality rates were not statistically significant at 20 and 40 days after restrictions were lifted. On-premises dining was associated with a 1.1% increase in cases at 100 days and a 3% increase in mortality at 100 days.

Daily mortality rates before restrictions were lifted were not statistically different from those during the reference period. There was a significant difference in cases between 41 and 60 days before restrictions were lifted.

The study covered county-level mask mandates across the US from March 1 through December 31, 2020.