Two new studies from the Centers for Disease Control and Prevention came to a similar conclusion on Friday: Schools that require masks see fewer COVID-19 outbreaks.
One study suggested that the odds of a COVID-19 outbreak were 3.5 times higher in schools that didn't require masks than those that did. The study examined more than 1,000 K-12 public schools in Arizona's most populous counties, Maricopa and Pima.
Schools that implemented mask mandates when the school year began saw fewer outbreaks overall: Just 8% of COVID-19 outbreaks recorded from July to August took place in schools with early mask mandates. Another 33% took place in schools that implemented mask requirements late, and 59% in schools with no mask requirement.
Across the US, counties with school mask mandates have also recorded fewer COVID-19 cases among kids overall, a second CDC study found. The study examined 520 counties from July to September, 62% of which didn't have a school mask requirement.
Over the two-week period before and after school started, counties with school mask requirements saw their COVID-19 rates rise by 16 daily cases per 100,000 children, on average. Meanwhile, counties without school mask requirements saw their COVID-19 rates rise by 35 daily cases per 100,000 children, as shown in the chart below.
The studies provide evidence that students can safely attend school in-person this fall.
Indeed, a third CDC study found that 96% of US public schools were able to remain fully open for in-person learning from August to September. Just 1.5% of those schools — 1,800 in total — temporarily closed due to COVID-19 outbreaks. The number of school closures was highest in the South.
Masks are key until young kids can get vaccinated
The CDC recommends a combination of strategies — masks, vaccines, testing, and social distancing — to prevent school outbreaks. But vaccines aren't authorized for kids under 12 yet.
Trials are still studying how well vaccines perform among younger age groups, and Pfizer expects to have data about the 5-to-11 age group any day now. Assuming that data is promising, the FDA could greenlight the shots for younger kids by late October. Moderna, meanwhile, expects to have data about its vaccine's efficacy among young kids later this fall or in early winter.
Even though young kids are less likely to develop severe COVID-19, they're still vulnerable.
"The Delta variant has created a new and pressing risk to children and adolescents across this country, as it has also done for unvaccinated adults," Dr. Lee Savio Beers, president of the American Academy of Pediatrics, wrote in an August letter to the FDA.
The letter called upon the FDA to "ensure that COVID-19 vaccines for children can be authorized as swiftly as possible."
