Elsevier

Annals of Epidemiology

Volume 57, May 2021, Pages 46-53
Annals of Epidemiology

Brief communication
Differences in rapid increases in county-level COVID-19 incidence by implementation of statewide closures and mask mandates — United States, June 1–September 30, 2020

https://doi.org/10.1016/j.annepidem.2021.02.006Get rights and content
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open access

Highlights

  • Nationwide data on effect of community mitigation policies on COVID-19 incidence are limited.

  • U.S. counties in states that closed for <60 days were more likely to have rapid increases in COVID-19 rates.

  • U.S. counties in states with mask mandates were 43% less likely to have rapid increases in COVID-19 rates.

  • Effects of mitigation measures are greater in less urban counties.

  • Statewide mask mandates and longer closures could help limit COVID-19 incidence.

ABSTRACT

Background and Objective

Community mitigation strategies could help reduce COVID-19 incidence, but there are few studies that explore associations nationally and by urbanicity. In a national county-level analysis, we examined the probability of being identified as a county with rapidly increasing COVID-19 incidence (rapid riser identification) during the summer of 2020 by implementation of mitigation policies prior to the summer, overall and by urbanicity.

Methods

We analyzed county-level data on rapid riser identification during June 1–September 30, 2020 and statewide closures and statewide mask mandates starting March 19 (obtained from state government websites). Poisson regression models with robust standard error estimation were used to examine differences in the probability of rapid riser identification by implementation of mitigation policies (P-value< .05); associations were adjusted for county population size.

Results

Counties in states that closed for 0–59 days were more likely to become a rapid riser county than those that closed for >59 days, particularly in nonmetropolitan areas. The probability of becoming a rapid riser county was 43% lower among counties that had statewide mask mandates at reopening (adjusted prevalence ratio = 0.57; 95% confidence intervals = 0.51–0.63); when stratified by urbanicity, associations were more pronounced in nonmetropolitan areas.

Conclusions

These results underscore the potential value of community mitigation strategies in limiting the COVID-19 spread, especially in nonmetropolitan areas.

Keywords

COVID-19
Closures
Mask mandates
Mitigation strategies

Cited by (0)

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

1

These authors contributed equally.