BACKGROUND AND PURPOSE:

• On June 9, 2020 the governor of Kansas enacted a state-wide mask mandate to stop the spread of COVID-19 in public spaces
  • Individual counties were able to opt out of the mandate
• Van Dyke et al. (MMWR, 2020) report on the incidence of COVID-19 in counties with and without the state mask mandate

METHODS:

• Data source
  • Data from the Kansas Health Institute
  • COVID case and population counts were accessed from USAFacts
• Study design
  • Mask mandate: Counties that did not opt out
  • Opted out of mask mandate: Opted out of the state mandate, as allowed by Kansas state law, and did not adopt their own mask mandate
  • Daily county-level COVID-19 incidence: Calculated as the 7-day rolling average number of new daily cases per 100,000 population
    • Before the government order (June 1–July 2)
    • After the government order (July 3–August 23)
    • Mandated and nonmandated counties were compared over time

RESULTS:

• Mask mandate compliance
  • Had a mask mandate: 24 counties | Accounted for 2/3 of Kansas population
  • Opted out of mask mandate: 81 counties
  • 54% mandated counties and 9% nonmandated counties had implemented at least one other public health mitigation strategy (e.g., limits on size of gatherings and occupancy for restaurants)
• After the governor’s mask mandate, COVID-19 incidence decreased among counties with a mask mandate, but increased among counties without a mask mandate
  • Had mask mandate: Mean decrease 0.08 cases per 100,000 per day | Net decrease of 6%
  • Opted out: Mean increase 0.11 cases per 100,000 per day | Net increase of 100%

CONCLUSION:

• Kansas counties that adopted a mask mandate decreased the incidence of COVID-19, while those counties that opted out saw a continued increase in cases, providing more evidence for the benefit of face masks for preventing the transmission of SARS-CoV-2
• The authors state

After implementation of mask mandates in 24 Kansas counties, the increasing trend in COVID-19 incidence reversed

…rates in mandated counties declined markedly after July 3, compared with those in nonmandated counties

Kansas counties that had mask mandates in place appear to have mitigated the transmission of COVID-19, whereas counties that did not have mask mandates continued to experience increases in cases

Learn More – Primary Sources:

Trends in County-Level COVID-19 Incidence in Counties With and Without a Mask Mandate — Kansas, June 1–August 23, 2020

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