Updated at 10:58 a.m. ET Wednesday
Data from K-12 schools that reopened for in-person instruction in the fall show little evidence that schools contributed meaningfully to the spread of COVID-19, according to a new article published Tuesday in JAMA, the journal of the American Medical Association.
The overview from the Centers for Disease Control and Prevention, authored by three of its scientists, represents the clearest view yet of the facts behind what has become a heated debate over when and how schools should reopen.
Last spring and into fall, schools across the country closed — and many remain closed — out of fear that allowing students and staff to return to school buildings would drive communitywide spread of the virus, much as nursing homes and crowded bars have done.
The CDC report says data from reopened classrooms show that "the type of rapid spread that was frequently observed in congregate living facilities or high-density worksites has not been reported in education settings in schools."
Among the school systems cited in the review were 11 North Carolina districts serving more than 90,000 students and staff. During a nine-week period this fall, researchers found just 32 infections acquired in school — compared with 773 cases of students and staff infected outside school. None of those 32 in-school transmissions involved students infecting teachers or staff.
In another study, of 17 schools in rural Wisconsin, mask-wearing helped keep the COVID-19 incidence lower in schools than in the larger community.
While the researchers call the findings "reassuring," they make clear that much of the success schools have had in preventing transmission is the result of their embrace of safety precautions.
"All recommended mitigation measures in schools must continue: requiring universal face mask use, increasing physical distance ... increasing room air ventilation, and expanding screening testing to rapidly identify and isolate asymptomatic infected individuals," the report says.
The CDC authors do single out a few school-based functions that can drive infections, namely indoor sports practices and events. They cite a pair of high school wrestling tournaments in Florida where 38 of the 54 participants who were tested, tested positive, some of whom brought the virus back to their families and friend circles. The report also serves as a reminder that schools do not operate in a vacuum. To keep COVID-19 out of classrooms, communities should be prepared to fight it elsewhere, including by restricting indoor dining.
The summary was published online as a "Viewpoint," and, though it was authored by CDC scientists, it included a disclaimer that its conclusions "do not necessarily represent the official position of the Centers for Disease Control and Prevention." But, when asked by NPR if the article's conclusions could be attributed to CDC, an agency spokesman confirmed that they could.
The report comes at an inflection point for the U.S., where more than 420,000 people have died from the disease and communities have been bracing for the arrival of more contagious coronavirus variants. At the same time, the federal government has begun a massive, if plodding, vaccination rollout. Some states have prioritized inoculating educators and school staff as teachers unions in some communities have resisted a return to school for safety reasons.
President Biden has pledged to help the majority of schools reopen within his first 100 days. His administration has proposed sending $130 billion in relief to K-12 schools to help pay for the kinds of costly mitigation efforts the CDC recommends, including socially distanced classrooms and ventilation updates for aging buildings.