Improving ventilation in elementary schools and requiring staff to wear masks significantly reduces transmission of coronavirus, a Centers for Disease Control and Prevention study released Friday found, backing up a nationwide push to reopen schools after over a year of on-and-off closures.
Looking at 169 Georgia elementary schools in November and December of last year, coronavirus cases among students and staff were 37% lower in schools with staff mask mandates, after adjusting for infection rates in the surrounding community.
Case counts were also lower if students were required to wear masks, but the difference wasn’t statistically significant, and the study’s authors think mask mandates were more effective with staff because adults are more vulnerable to Covid-19.
Ventilation also put a dent in coronavirus cases: Schools reported 35% fewer infections if they just diluted the air indoors by opening windows and plugging in fans, and schools saw a 48% drop in cases if they also installed HEPA air filters.
One caveat: The data was collected months before the more contagious B.1.1.7 coronavirus variant — first discovered in the United Kingdom — became the dominant strain in the United States, and it’s been blamed for a rise in cases among American children.
“[Findings] in this report suggest universal and correct mask use is an important COVID-19 prevention strategy in schools as part of a multicomponent approach,” the study said.
Federal officials are pushing all school districts to return to full-time in-person classes by next fall, phasing out the hybrid and virtual instruction that some schools are still conducting more than a year after the pandemic first started. The CDC says in-person learning “has not been associated with substantial community transmission,” but the agency encourages schools to minimize the risk through ventilation, social distancing and mask-wearing. Most — but not all — studies say the risk of reopening is fairly low, especially if schools take precautions.
What To Watch For
The risk of Covid-19 in schools could drop further if more students are vaccinated. Federal regulators authorized Pfizer’s vaccine for Americans ages 12 to 15 last week, and drugmakers are testing their vaccines on even younger children. Vaccination rates remain fairly low for minors: Some 8.9% of children ages 12 to 15 and 31.8% of 16 and 17 year olds have received at least one vaccine dose, according to CDC data updated Thursday.