Department of Research & Evaluation News

A year-long study of mask adherence and social distancing among more than 100,000 people in 126 U.S. cities found people were 3 times more likely to wear masks correctly in places where a mask mandate was in place. The study was published recently in the American Journal of Infection Control.

“City, county, and state leaders can have a powerful influence on whether people protect themselves with masks from COVID-19 infection,” said the senior author on the research, Deborah Cohen, MD, of the Kaiser Permanente Southern California Department of Research & Evaluation.

The national observational study was conducted from September 2020 through August 2021. Faculty from 16 different U.S. colleges and universities trained students to document whether people wore masks correctly and whether they maintained a 6-foot distance from other people in public settings. These student observers and others spread out to 126 cities across the United States in commercial settings such as retail centers and public streets, and non-commercial areas such as parks, playgrounds, and trails.

In total, 109,999 people were observed in these outdoor settings.

• 48% wore masks correctly with the highest adherence among females, teens, and seniors, and the lowest adherence among whites, people who were engaged in vigorous exercise, and people in large groups.
• Having a local mask mandate increased the odds of wearing a mask by nearly 3-fold compared to places with no mandates.
• People in non-commercial areas such as parks were less likely to wear masks than people in commercial areas.
• Correct mask use was greatest in December 2020 and remained high through June 2021.
• Most likely to socially distance were seniors, males, people who were Black or African American, and those engaged in vigorous exercise.
• Masking policy requirements were not associated with social distancing.

“The strong association we found between mask mandates and correct mask use suggests that public policy has a powerful influence on people’s behavior and should be considered in the future to control disease contagion,” Dr. Cohen said.

This study was funded by National Heart, Lung, and Blood Institute and Resolve to Save Lives, which did not have any role in the study design or preparation of the manuscript.

Authors on the study included lead author, Eric J. Puttock, PhD, of the Department of Research & Evaluation. Other authors from the Department of Research & Evaluation included Deborah R. Young, PhD, Abraelle M. Shirley, MPH, and Bing Han, PhD. Other authors included Jose Marquez and Iveris Martinez, PhD, California State University Long Beach; Thomas L. McKenzie, PhD, San Diego State University; Nicole J. Smith, PhD, California State University, Fresno; Kathleen Manuel, PhD, and Deanna Hoelscher, PhD, University of Texas; Suzanne Spear, PhD, California State University, Northridge; Monica Ruiz, PhD, George Washington University; Charlotte Smith, PhD, University of California, Berkeley; Kimberly Krytus, PhD, University at Buffalo; Hosung So, PhD, California State University, San Bernardino: Marian Levy, DrPH, and Vikki Nolan, DSc, The University of Memphis;, Erika Bagley, PhD, Muhlenberg College; Amber Mehmood, MBBS, University of South Florida; Joy Goens Thomas, MSPH, Mercer University; Lily Apedaile, University of Montana; Shelby Ison, University of Illinois; Daheia J. Barr-Anderson, PhD, University of Minnesota; John G. Heller, MPH, University of Oklahoma.