The coronavirus variant discovered in Britain is more easily spread among children, as it is among adults. Current safeguards should protect schools, experts said, but only if strictly enforced.
It wasn’t until last fall that many parents started to breathe easier, as it became clear that elementary schools, at least, were not cesspools of infection with the coronavirus. But the alarming news of a more contagious version of the virus, first identified in Britain, revived those concerns.
Initial reports were tinged with worry that children might be just as susceptible as adults, fueling speculation that schools might need to pre-emptively close to limit the variant’s spread. But recent research from Public Health England may put those fears to rest.
Based on detailed contact-tracing of about 20,000 people infected with the new variant — including nearly 3,000 children under 10 — the report showed that young children were about half as likely as adults to transmit the variant to others. That was true of the previous iteration of the virus, as well.
“There was a lot of speculation at the beginning suggesting that children spread this variant more,” said Muge Cevik, an infectious disease expert at the University of St. Andrews in Scotland and a scientific adviser to the British government. “That’s really not the case.”
But the variant does spread more easily among children, just as it does among adults. The report estimated that the new variant is about 30 percent to 50 percent more contagious than its predecessors — less than the 70 percent researchers had initially estimated, but high enough that the variant is expected to pummel the United States and other countries, as it did Britain.
Prime Minister Boris Johnson of Britain had promised last year to do all he could to keep schools open. But he changed course in the face of soaring infections and buckling hospital systems, and ordered schools and colleges to move to remote learning. Other European countries put a premium on opening schools in September and have worked to keep them open, though the variant already has forced some to close.
In the United States, the mutant virus has been spotted only in a handful of states but is expected to spread swiftly, becoming the predominant source of infections by March. If community prevalence rises to unmanageable levels — a likely proposition, given the surge in most states — even elementary schools may be forced to close.
But that should be a last resort, after closures of indoor restaurants, bars, bowling alleys and malls, several experts said.
“I still say exactly what many people have said for the past few months — that schools should be the last thing to close,” said Helen Jenkins, an infectious disease expert at Boston University. Keeping schools open carries some risk, but “I think it can be reduced substantially with all the mitigations in place,” she said.
Reports of the new variant first surfaced in early December, and some researchers initially suggested that unlike with previous versions of the virus, children might be just as susceptible to the new variant as adults.
Researchers at P.H.E. looked at how efficiently people of various ages transmitted the variant to others. They found that children under 10 were roughly half as likely as adults to spread the variant.
Adolescents and teenagers between ages 10 and 19 were more likely than younger children to spread the variant, but not as likely as adults. (The range for the older group in the study is too broad to be useful for drawing conclusions, Dr. Cevik said. Biologically, a 10-year-old is very different from a 19-year-old.)
Over all, though, the variant was more contagious in each age group than previous versions of the virus. The mutant virus will result in more infections in children unless schools shore up their precautions, experts said.
“The variant is not necessarily affecting children particularly, but we know that it’s adding on more transmissibility to all age groups,” Dr. Cevik said. “We need to find ways to return these kids back to school as soon as possible; we need to use this time period to prepare.”
In Germany, Chancellor Angela Merkel had vowed that schools would be the last thing to close during the second lockdown that began in November. Schools went to great lengths to keep in-person classes in session, requiring children to wear masks and opening windows to ensure better ventilation even as temperatures plummeted.
But fear of the variant’s spread prompted Ms. Merkel to keep schools closed following the holiday break at least through the end of January.
In France, where the new variant has not resulted in a surge of infections so far, schools reopened earlier this month after the winter break. France was not dealing with a particularly difficult epidemic, and health protocols put in place last September limited transmission in schools, Jean-Michel Blanquer, France’s education minister, has said.
The Italian government, too, has allowed not just elementary schools to open but also high schools, albeit at half capacity. Still, local leaders have implemented tighter restrictions, with some high schools slated to stay closed until the end of the month.
In the United States, the variant has only been spotted in a handful of states, and still accounts for less than 0.5 percent of infections. Schools remain open in New York City and many other parts of the country, but some have had to shut down because of rising virus infections in the community.
“Obviously, we don’t want to get to a point where it seems like we closed schools too late,” said Dr. Uché Blackstock, an urgent care physician in Brooklyn and founder of Advancing Health Equity, a health care advocacy group. “But at the same time, I think that we should try to keep our young children in school for as long as possible for in-person learning.”
It’s been clear for months what measures are necessary, Dr. Blackstock and other experts said: requiring masks for all children and staff; ensuring adequate ventilation in schools, even if just by opening windows or teaching outdoors; maintaining distance between students, perhaps by adopting hybrid schedules; and hand hygiene.
The new variant, while more contagious, is still thwarted by these measures. But only a few schools in Britain implemented them.
“When we look at what’s happened in the U.K. and think about this new variant, and we see all the case numbers going up, we have to remember it in the context of schools being open with virtually no modification at all,” Dr. Jenkins said. “I would like to see a real-life example of that kind of country or state or location, which has managed to control things in schools.”
There are some examples within the United States.
Erin Bromage, an immunologist at the University of Massachusetts Dartmouth, advised the governor of Rhode Island, as well as schools in southern Massachusetts, on preventive measures needed to turn back the coronavirus. The schools that closely adhered to the guidelines have not seen many infections, even when the virus was circulating at high levels in the community, Dr. Bromage said.
“When the system is designed correctly and we’re bringing children into school, they are as safe, if not safer, than they would be in a hybrid or remote system,” he said.
The school Dr. Bromage’s children attend took additional precautions. For example, administrators closed the school a few days before Thanksgiving to lower the risk at family gatherings, and operated remotely the week following the holiday.
Officials tested the nearly 300 students and staff at the end of that week, found only two cases, and decided to reopen.
“That gave us the confidence that our population was not representative of what we were seeing in the wider community,” he said. “We were using data to determine coming back together.”
The tests cost $ 61 per child, but schools that cannot afford it could consider testing only teachers, he added, because the data suggest the virus is “more likely to move from teacher to teacher than it is from student to teacher.”
In New York City, students and teachers are randomly tested, and have so far shown remarkably low rates of transmission within schools.
Dr. Blackstock has two children at an elementary school in Brooklyn, and said her son has not been tested all year. Even if the new variant brings a spike in cases, the city’s policy of closing a school if it has two unrelated infections is “too conservative,” she said.
If the number of cases skyrockets and the schools shut down more often, “then I would probably say, ‘This doesn’t feel right, let’s keep them home,’” she said. “But they’re going to be in school as long as I can possibly keep them.”
Emma Bubola contributed reporting from Milan, Melissa Eddy from Berlin, Constant Méheut from Paris and Benjamin Mueller from London.