The Centers for Disease Control and Prevention published studies showing that so-called “test-to-stay” strategies, relying on at least two tests a week, didn’t lead to more student cases than schools that sent exposed kids home outright. 

The strategy “allows unvaccinated children to stay in school, even if they have been exposed to the virus, so that they don’t have to miss school while they’re quarantining at home,” CDC Director Rochelle Walensky said Friday in a press briefing. She called it a “promising and now proven practice.” 

The studies relied on certain criteria, including the use of masks, and that students exposed to a case had to remain asymptomatic. The two studies set different testing intervals—California required two tests in a week, while Illinois required four—but generally found no examples where an exposed student relayed the virus to a third one.

“These studies demonstrate that test-to-stay works to keep vaccinated children in school safely,” provided other prevention measures are also included, like masks and monitoring for symptoms, Walensky said. “Test-to-stay is an encouraging public health practice to keep our children in school.”

A U.S. surge in Omicron COVID cases is “inevitable,” White House medical adviser Anthony Fauci said in the briefing. President Joe Biden’s administration has staked out school reopenings as a sign of success fighting the virus, and signaled this week that it doesn’t plan to recommend closures in the face of the highly mutated variant. 

Biden warned Thursday that the variant will wreak havoc on the unvaccinated, their families and hospitals that are already overwhelmed, and begged people to get vaccines and boosters. “We’re going to keep schools and businesses open if we do this,” he said. 

Testing capacity

A test-to-stay school strategy, however, will rely on substantial testing capacity. Demand is already spiking across the country, and Biden’s administration has faced pressure over shortages of affordable at-home rapid tests.

The supply chain for COVID-19 testing is still not where it needs to be to enable this type of strategy in every school district, Romney M. Humphries, medical director of Vanderbilt University Medical Center’s Clinical Microbiology Laboratory, said in an Infectious Diseases Society of America briefing on Dec. 15.

“Running a clinical lab, I still deal with trying to get COVID testing reagents on a weekly basis,” she said. “These are great strategies, but we do need to be able to resource them appropriately for them to be effective. And we’re really still not quite there yet with the testing supplies.”

To be successful, testing strategies need adequate resources, Joshua Barocas, an associate professor of medicine at the University of Colorado, added during the IDSA call.

“The test-to-stay strategy is a very good strategy,” Boracas said, “but we have to understand that different school districts have different resources.”