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Mask mandates in school reduce COVID-19 cases among students, staff, and members of the community
Clinical Question
Do requirements for the use of face masks in schools reduce COVID-19 cases in children, staff, and members of the community?
Bottom line
School systems with mask mandates have a lower incidence of COVID-19 among students and staff than school systems with partial or no mask mandates. The benefit extends to the community, with fewer cases of COVID-19 in communities where schools had mask mandates. 2c
Reference
Study design: Time series
Funding: Government
Setting: Population-based
Synopsis
An area of continuing controversy in the COVID-19 pandemic is the requirement for children to wear face masks in schools. Previous studies have shown a benefit, including one study in Arizona schools during the late summer of 2021. The current study was set in Arkansas and compared K-12 school districts with full or partial mask mandates with districts that had no mandate. (A partial mandate limited mask requirements to certain settings or populations.) The authors first calculated incidence rate ratios adjusted for vaccination rates, weekly community attack rates, and the percentage of kids getting free or reduced cost lunches as a proxy for socioeconomic status and disparities. They found that COVID-19 incidence among students and staff was significantly lower in districts with full mask policies than those with no mask requirements (incidence rate ratio [IRR] 0.77; 95% CI 0.66 - 0.88). Partial mask policies did not result in a similar reduction. A second analysis looked at cases before and after a mask mandate was implemented in a district, which found a large drop in student and staff infection rates, from more than 800/100,000 per week to less than 400/100,000. Community infections dropped as well, from approximately 400/100,000 per week to less than 300/100,000. Finally, a third calculation of the ratio of observed to expected cases was highest (ie, worst) in districts with no mask policies. A caveat: This study took place during the Delta wave, and results may be different with the more transmissible Omicron variant.
Reviewer
Mark H. Ebell, MD, MS
Professor
University of Georgia
Athens, GA
Comments
Very informative
Everyone has to wear mask in malls religious places etc
Masks and NNT
I am disappointed that this particular POEMs writers abandon the idea of evidence-based medicine and forgot to represent the information in the most comprehensible way. I suspect we may shy away from saying that 1000 people need to wear masks in community to prevent one case of infection. The mask wearing in the schools would need 250 students to wear a mask to prevent one case infection. Nevertheless, this will be more understandable and will re-iterate the available information on effectiveness of mask wearing for COVID transmission prevention. This will, of course, depend on prevalence of COVID in various phases of pandemics. Therefore the effectiveness can go up and down significantly in real world settings.
Other data
The report failed to mention other US school studies that found no benefit.
The study is consistent with pre-covid studies in universities that found a 4% reduction in influenza with a mask mandate. So it seems likely the study is a valid indicator of efficiency.
mask mandates in schools
decreases incidence of covid