I lead with the money quote:
Schools that required universal masking for adults and students saw 72 percent fewer secondary infections—in which students infected with COVID-19 in the community spread the virus to others in school—than did schools that had no mask requirements or partial masking.
Mask Mandates Cut COVID-19 Spread in Schools, Studies Find
Mask requirements still offer one of the strongest tools to prevent COVID-19 outbreaks in schools, say new studies.
The findings come from the Centers for Disease Control and Prevention and from a nationwide
study published this morning in the journal Pediatrics. They land as the latest pandemic wave recedes, federal masking guidelines begin to relax, and education leaders work toward more flexible approaches to masking for staff and students.
But the data offer the strongest evidence to date on the effectiveness of masking in curbing COVID spread in schools, regardless of whether or not students are vaccinated.
In the Pediatrics study, Duke University researchers in the ongoing
ABC Science Collaborative—which tracks pandemic mitigation efforts in schools—analyzed masking policies and infection rates in 61 districts, more than 3,000 schools, and more than 1.1 million students and adults in nine states. For the first time, the national study looked at mitigation from July through December 2021, during the delta wave and the start of the omicron waves of the pandemic.
Schools that required universal masking for adults and students saw 72 percent fewer secondary infections—in which students infected with COVID-19 in the community spread the virus to others in school—than did schools that had no mask requirements or partial masking. Once school size, vaccination rates, and other characteristics were taken into account, schools with universal masking had nearly 90 percent lower infection rates.
Moreover, about half of the students and staff in the study had completed vaccination against COVID-19 by the end of the study, and Duke researchers found universal masking policies were associated with fewer infections even among those who were already vaccinated.
https://www.edweek.org/leadership/mask-mandates-cut-covid-19-spread-in-schools-studies-find/2022/03