• Health
  • COVID-19

Here’s What the Science Actually Says About Kids and COVID-19

7 minute read

Benjamin Knorr, a 40-year-old single father in Janesville, Wisc., says there’s about a 50-50 chance he’ll send his two teenage sons back to school this fall. His 13-year-old, Aiden, would especially like to get back to his friends, sports, and regular life. But Knorr, an independent contractor, has asthma, and fears that his health and finances would be imperiled if one of his boys brought COVID-19 home from school.

“If the numbers go up in Dane County and Rock County, where I work and live, it’s over. We’re just doing the online school,” Knorr says. “We already got through two months of it, and yeah, it was hard. It was stressful. And yeah, it was more work on my part to come home and do the online schooling with them and stuff. But we can’t be homeless.”

As school districts across the United States decide whether to welcome kids back into the classroom for in-person education this fall, administrators find themselves weighing a complex set of variables. There’s the risk of children, teachers and staffers getting sick or spreading the disease, on the one hand. But on the other, there’s evidence that being out of school can degrade children’s long-term learning prospects and mental health; make it harder for many to get the food they need; and make it difficult for parents to work—especially mothers, who are often expected to handle a disproportionate amount of childcare duties. Millions of students, meanwhile, lack access to high-speed broadband internet and other technological resources required to get the most out of remote learning, making it an inadequate substitute for many.

Meanwhile, the debate over reopening schools has become intensely politicized. U.S. President Donald Trump and many other Republicans are pressuring schools to reopen, in part because they want American life to feel as normal as possible before Election Day this November. But many Democrats say it’s too early to go back to school, and we shouldn’t put the lives of children and teachers at risk before a vaccine is ready.

Putting politics aside, what the science so far shows is this: young kids may be less likely to get sick from COVID-19 and rarely get very ill if they do show symptoms, and they seem to be less likely to infect other people. This June study, which examined epidemiological data from China and five other countries, found that people under 20 are about half as likely to get infected as older people, and only 21% of people between 10 and 19 years old who become infected show symptoms.

Complicating matters in the U.S., experts tell TIME, is that American schools closed early in the pandemic and have since remained shuttered; therefore, we don’t have very good data about the way the virus spreads in U.S. classrooms. The best we do have so far comes from a large South Korean study published earlier this month. After contact tracing about 5,700 COVID-19 patients, researchers found that kids under the age of 10 spread the virus at about half the rate of adults, but kids between 10 and 19 spread it at a similar rate as adults (although the study included fewer people from that age group than adults). That suggests administrators and policymakers need to think differently about middle and high schoolers than they do younger students. “My take home from that is that it’s an age continuum,” says Dr. William Raszka, a pediatric infectious disease specialist at the University of Vermont. “The older you are, the more likely it is you’re going to have transmission similar to adults.”

The findings out of South Korea comport with those of other, smaller studies. Research into French primary schools released as a pre-print in June found no evidence of transmission by children in schools; and research from Iceland published in April found that children under 10 were less likely to test positive for the virus than those over 10. Another small study published in July, based on data from hospitals in the Chinese cities of Wuhan and Qingdao, found that, among 68 pediatric COVID-19 patients, 96% were infected by another adult in their household, and there was no evidence that the children transmitted the virus to others (it’s unclear from the study how the other 4% of children became infected).

There could be a number of reasons that younger people are less likely to spread COVID-19, says Justin Lessler, an epidemiologist at Johns Hopkins Bloomberg School of Public Health. The virus may not replicate in children as much as it does in adults, meaning an infected child would have less viral material to pass on. Furthermore, because children generally have no or less severe symptoms, they may be less likely to spread the virus by coughing or sneezing, as a sick adult might.

Still, that could be a mixed blessing, says Lessler—if a child is infected but doesn’t seem sick, they could be sent to school and wind up infecting others. “It’s a trade-off,” he says. “If they’re not shedding a lot of virus, it may be less likely, but they may be having a lot more contact because they’re not ill.” Absent proper health safeguards, that could be big trouble for schools. School-age children typically have more contact with other people than adults while school is in session. And even if they’re not coughing or sneezing, children are generally pretty good at spreading disease through other habits, like touching everything in sight or crying.

Another big unknown is whether children who are asymptomatic or pre-symptomatic can spread the virus—Dr. Yvonne Maldonado, a pediatric infectious disease physician and epidemiologist at Stanford Medicine, points out that the aforementioned South Korean study only traced the contacts of symptomatic children.

One thing we do know: about a quarter of U.S. teachers are at higher risk of severe illness from COVID-19, according to a July analysis by the Kaiser Family Foundation, because they are over 65, have a preexisting condition such as chronic obstructive pulmonary disease (COPD), or a body mass index over 40. And unfortunately, discussions over kids’ vulnerability to COVID-19 frequently sidesteps the issue of whether reopening schools puts teachers’ and other staffers’ lives on the line. Randi Weingarten, the head of the American Federation of Teachers, gave the green light on July 28 for union members to go on so-called “safety strikes” in protest of unsafe working conditions. “If authorities don’t protect the safety and health of those we represent and those we serve,” she told union members, NPR reports, “nothing is off the table.”

There are ways to help reduce risk, says Maldonado: precautions like social distancing, having teachers wear masks and face shields, and splitting children into smaller groups and staggering their school days can all help. (Some of those measures, especially social distancing, will be tougher in jam-packed schools or in schools with fewer resources.) “We have not seen transmission when you take the proper precautions,” Maldonado says. “So what I would want to know as a parent is, what is my school doing to make sure those precautions are in place. And that’s the key. If the school can do it, then I would feel comfortable. If the school seems like they really don’t have their act together, or they don’t have the resources, then I might be worried about that.”

Whether a given school or district can safely reopen may ultimately be tied to the situation in the community more broadly—if a given state or county is experiencing a significant outbreak, it may be wise to keep the school doors closed.

“You cannot easily separate schools from the community,” says Raszka, the University of Vermont specialist. “They’re not totally separate. And if you really want to minimize the risk of transmission in schools, then you should minimize the risk in the community.”

More Must-Reads from TIME

Contact us at letters@time.com