There's "little evidence that schools have contributed meaningfully to increased community transmission" of the novel coronavirus, according to a new JAMA report from CDC researchers. But they cautioned success was predicated on both precautions taken at school and within the broader community.

CDC finds in-person schooling doesn't lead to increased coronavirus transmission

In the report, CDC reviewed several studies assessing coronavirus transmission in schools, including three domestic studies and two international ones.

One study that looked at 17 elementary and secondary schools in Wisconsin, where consistent mask-wearing among staff and students appeared to correlate with the schools reporting infection rates 37% lower than those in the community. Specifically, the researchers found that, during 13 weeks of the fall of 2020, 191 infections were reported among staff and students, but just seven of those infections were a result of in-school transmission.

Another study in the review, this one focused on Mississippi, found that while children who attended small gatherings outside their home and had people over their house had a higher risk of being infected with the novel coronavirus, those attending school did not.

And in a third study, which focused on 11 school districts in North Carolina with more than 90,000 students and staff, researchers found that in-school transmission of the novel coronavirus was "very rare." Overall, the study identified just 32 total infections acquired in school, compared with 773 acquired within the community. The researchers also found no instances of viral transmission between students and staff.

The researchers also assessed two international studies. One, a report from Israel, identified a large outbreak in a high school—although, in that case, the rooms were crowded, mask-wearing wasn't universal, and there was poor ventilation—while the other, from Europe, found schools were not contributing to an increase in community spread.

As a result of the available evidence, the researchers concluded that in-person schooling could safely resume only if certain precautions were implemented, including mandatory mask-wearing, limiting students' exposure by keeping them in cohorts, enabling people to be six feet apart, screening tests to identify anyone who may be asymptomatic, and increasing air ventilation.

"Back in August and September, we did not have a lot of data on whether or not we would see the same sort of rapid spread in schools that we had seen in other high-density work sites or residential sites," Margaret Honein, a member of CDC's Covid-19 emergency response team and first author of the report, said. "But there is accumulating data now that with high face mask compliance, and distancing and cohorting of students to minimize the total number of contacts, we can minimize the amount of transmission in schools."

CDC recommends certain precautions—inside and outside of school

CDC also recommended that certain restrictions should be implemented in the community at large in order to safely reopen schools, including placing restrictions on indoor dining, bars, and gyms that are poorly ventilated, in an effort to reduce overall community infection rates.

In addition, CDC recommended limiting certain extracurricular activities. Specifically, a separate CDC report noted two high school wrestling tournaments that took place in Florida in December 2020 where 30% of the 130 athletes, coaches, and referees tested positive for the novel coronavirus. Following the tournament, 95 additional people in close contact with those infected were tested and 43% came back positive. Ultimately, the tournament led to at least 79 infections and one death.

"It's not going to be safe to have a pizza party with a group of students," Honein explained. "But outdoor cross-country, where distance can be maintained, might be fine to continue."

Separately, Emily Oster, a professor of economics and public policy at Brown University and creator of the Covid-19 School Response Dashboard, said, "Prioritizing schools is going to mean limiting some of those other activities, and deciding that we want to undertake some of those sacrifices to keep schools open, because we've decided as a society that schools are important relative to other things" (Rabin, New York Times, 1/26; Meckler, Washington Post, 1/26; Chander, Reuters, 1/26; Turner, NPR, 1/26).