Publisher Health

When the schools in Marietta, Ga., opened their doors on Aug. 3, the highly contagious Delta variant was sweeping across the South, and children were not being spared.

By Aug. 20, 51 students in the city’s small school district had tested positive for the coronavirus. Nearly 1,000 others had been flagged as close contacts and had to quarantine at home for seven to 10 days.

“That’s a lot of school, especially for children that are recovering from 18 months in a pandemic where they missed a lot of school or had to transition to virtual,” said Grant Rivera, the superintendent of Marietta City Schools.

Last week, the district changed tack. Students who are identified as close contacts can now continue attending school as long as they have no symptoms and test negative for the virus every day for seven days.

An increasing number of school districts are turning to testing to keep more children in the classroom and avoid disrupting the work lives of their parents. The resource-intensive approach — sometimes known as “test to stay” or modified quarantine — allows students who have been exposed to the virus to stay in school as long as they take frequent Covid tests, which are typically provided by the school, and adhere to other precautions.

Experts agree that children who are infected with the virus should isolate at home, but the question of what to do about their classmates poses a dilemma.

Allowing children who have been exposed to the virus to remain in school does pose a potential transmission risk, and the Centers for Disease Control and Prevention says that it “does not have enough evidence” to support the approach. Instead, it recommends that close contacts who have not been fully vaccinated quarantine for as long as 14 days. (Vaccinated close contacts can remain in the classroom as long as they are asymptomatic and wear a mask, according to the agency’s school guidance.)

“At this time, we do not recommend or endorse a test-to-stay program,” the C.D.C. said in a statement to The New York Times. The agency added, “However, we are working with multiple jurisdictions who have chosen to use these approaches to gather more information.”

The C.D.C. guidelines mean that a single case of Covid in an elementary school, where students are generally too young to be vaccinated, can force an entire classroom of children out of school. New York City’s school guidelines also stipulate that all unvaccinated students must quarantine for seven to 10 days if one of their classmates contracts the virus.

With the academic year barely underway, some districts in Florida, Louisiana, Missouri and other Covid hot spots have already had to quarantine hundreds or even thousands of students. In mid-August, Mississippi had nearly 30,000 students in quarantine, according to data reported to the state.

A new study, which was published last week in The Lancet, suggests that the test-to-stay approach can be safe. The randomized controlled trial included more than 150 schools in Britain, and found that case rates were not significantly higher at schools that allowed close contacts of infected students or staff members to remain in class with daily testing than at those that required at-home quarantines.

Roughly 2 percent of school-based close contacts ultimately tested positive for the virus, researchers found, which means that schools were keeping 49 uninfected students out of class every time one student tested positive.

“When you put that in the broader context of what we’re doing in society, it’s putting a pretty strong penalty on young people, I think,” said Dr. Bernadette Young, an infectious disease expert at the University of Oxford and a lead author of the paper.

This summer, the United Kingdom announced that children identified as close contacts no longer needed to quarantine, although it encouraged them to be tested for the virus.

As school officials embark on a third pandemic academic year, many say the time has come for a new approach.

“The philosophy of this is how can we keep healthy kids in school and sick kids at home?” said Isaac Seevers, the superintendent of Lebanon City Schools in Ohio, which is preparing to start a test-to-stay program. “I think there’s some real optimism that this is a game-changer for how we learn to live with Covid.”

Testing trials

Melissa True Gibbs, a mother of two teenagers in Sandy, Utah, prefers not to think about last fall. “It was hell,” she said.

In August, her soccer-playing daughter, Lydia, and theater-loving son, Brody, trudged off to Alta High School.

By late September, with Covid cases on the rise, the school shut its doors and transitioned to online learning. Two weeks later, it shifted to a hybrid schedule — in which students came to school on some days and learned from home on others — and then back to in-person and then back to hybrid and then back to entirely online as case numbers rose again.

“My kids are pretty resilient,” Ms. True Gibbs said. “But man, that first half of that year, I saw things happening with my kids that scared me. They weren’t emotionally well, they weren’t mentally well, they were struggling.”

Many other schools in Utah were having similar experiences. So as winter approached, officials developed a test-to-stay protocol. Small schools that had 15 cases, or larger ones that had a 1 percent infection rate, could either switch to online learning or hold a mass testing event. Students who tested negative could return to class, while those who were infected, or whose families did not consent to the testing, would stay home.

Thirteen schools, including Alta High, conducted test-to-stay events early this year. Just 0.7 percent of 13,809 students tested positive, researchers reported in May.

“That made us feel really confident that continuing in-person learning in these schools was the right call,” said Dr. Adam Hersh, an expert in pediatric infectious diseases at the University of Utah and a co-author of the paper.

The program saved more than 100,000 in-person student-days last winter, the researchers found.

Ms. True Gibbs said that the testing program allowed her children, who tested negative, to keep going to class, practice and rehearsal. “For my kids, it made them feel safer, because they knew the students who were at school weren’t sick,” she said.

In March, the state enacted a law requiring schools to hold test-to-stay events when they hit certain outbreak thresholds.

Other schools and districts have adopted similar solutions, focusing on testing only students who had been identified as close contacts.

Some states, including Illinois, Kansas, California and Massachusetts, have now outlined their own test-to-stay or modified quarantine protocols, as have some local districts elsewhere. More than 2,000 schools in Massachusetts are using the state’s procedure, which allows close contacts to stay in school as long as they are asymptomatic, wear a mask and test negative for the virus daily for seven days after exposure.

Mixed opinions

Many parents across the country are thrilled about the new approach. For Monica Fambrough, who has twin daughters in second grade and a son in fifth grade in school in Marietta, the first six weeks of school had been harrowing.

“We have, every Friday, sort of done a little cheer — we made it through the week without getting quarantined,” she said. “I just feel like every day that I send them to school, we’re kind of rolling the dice that we’re going to get a close-contact notice. And so having the option to keep them in school, even if they are a close contact, is a very big deal for my family.”

Attending class in person is not only a better educational experience for her children, she said, but also a boon for her and her husband, both of whom work at home.

But Jennifer Shotwell, who has children and grandchildren in school in Missouri, worried that allowing close contacts to remain in school could put vulnerable children — like her granddaughter, who has an autoimmune disorder — at risk. “If I could have my way, modified quarantine would not be used in her classroom at all until students can be vaccinated,” she said.

And some localities have more stringent guidelines than others. While Massachusetts and Marietta require daily testing for close contacts, Illinois calls for testing every other day and California’s guidelines stipulate twice-weekly testing.

Some districts have solved the problem of disruptive quarantines by abandoning the practice altogether. “If you’re a close contact, we’re not requiring that you stay home for a quarantine period,” said Joe Koch, the deputy superintendent of the school district of Waukesha, Wis. The school board has taken the approach that “essentially it’s up to you how you want to manage Covid for yourself,” he said.

Making it work

For the test-to-stay approach to work, the tests must be readily available and easily accessible. Relatively few families have opted into Marietta’s program so far, perhaps because they don’t have transportation to the district’s central testing site, Dr. Rivera said. (The district hopes to expand the number of testing sites soon.)

In Bay County, Mich., more than 300 students have already been identified as close contacts, said Joel Strasz, the county’s health officer.

“We require that the test be done on site prior to entry to school,” Mr. Strasz said of the test-to-stay protocol. “It’s pretty manageable if you only have to test five or 10 kids. But when you’ve got to test close to 100, then that can be challenging, and we had to scramble to get resources to the schools.”

Test-to-stay programs are most feasible when paired with other safety measures, including masking, experts said. Utah, which required masks in schools last year, has banned such mandates this year, and some districts have decided not to do any testing at all unless they hit the outbreak threshold, said Kendra Babitz, the state’s Covid testing director.

Robust testing is a “really important” strategy for supporting in-person learning, Dr. Hersh said. “But it’s operationally challenging. So to the extent that we can reduce the frequency with which we need to be concerned about close contact exposures, and all that goes with that, we’re going to be creating much more sustainable learning environments.”