The Effectiveness of Face Mask Mandates on COVID-19 Transmission in Utah.

Objective: Throughout the COVID-19 pandemic, the effectiveness of face mask mandates was intensely debated. The objective of this study was to describe how face mask mandates at the state, county, and local levels differed in their effectiveness in reducing the number of COVID-19 cases in the jurisdiction where the mandate was implemented and throughout Utah.

Methods: We used publicly available data from the Utah Department of Health and Human Services. We calculated the effectiveness of face mask mandates () in each local health district after 3 key mandates: the enactment of face mask mandates in Salt Lake and Summit counties (SLSC) on June 28, 2020, and June 27, 2020, respectively; the enactment of a statewide face mask mandate on November 9, 2020; and the lifting of the statewide face mask mandate on April 10, 2021.

Results: Most counties in Utah had a reduction in the growth rate of COVID-19 cases after enactment of face mask mandates. We found an average 11.9% reduction in after the introduction of the SLSC face mask mandates, with 8 of 13 local health districts experiencing a reduction, and an average 12.7% reduction after introduction of the statewide mandate, with 12 of 13 local health districts experiencing a reduction. After mandates were lifted, many counties had an increase in .

Conclusion: Face mask mandates were an effective way to reduce transmission of COVID-19 in local jurisdictions and in neighboring jurisdictions in Utah. Our evidence supports the use of face mask mandates as a way to prevent disease transmission and be better equipped to respond to future pandemics.