Schools aren't low-risk when it comes tocoronavirus transmission.- Studies have also shown that school closures significantly reduced infections and deaths.
- New research suggests that
children under age 5 have particularly high amounts of virus in their respiratory tracts. - But some public-health experts say reopening schools is worth the risk nonetheless.
There's a strong case for reopening schools in the US: Remote learning has already stymied children's progress and led to higher rates of absenteeism, particularly among low-income students, who are more likely to lack internet access. Millions of children also rely on school lunches for regular meals. And working from home is difficult or impossible for many parents, which in turn leads to devastating financial consequences for families and economic damage in the US as a whole.
But a growing body of research suggests that schools can be high-risk when it comes to coronavirus transmission, since children may be just as infectious as adults.
That was evident during a June outbreak at an overnight camp in Georgia, where three-quarters of the campers tested for the coronavirus (most of whom were under 18) wound up with positive results. Children ages 6 to 10 saw the highest rate of infections — 51% — compared to 44% for campers ages 11 to 17 and 33% for those ages 18 to 21.
What's more, children under 5 may have between 10 and 100 times more virus in their upper respiratory tracts than adults, according to a research letter published in the journal JAMA Pediatrics. Children ages 5 to 17, meanwhile, had roughly the same amount of virus in their upper respiratory tracts as adults.
"Young children can potentially be important drivers of SARS-CoV-2 spread in the general population," the researchers wrote, adding that "close quarters in school and day-care settings raise concern."
A recent New York Times analysis found that more than 80% of Americans live in a county where a school of 500 students and staff would see at least one infection within the first week of reopening. The risk was particularly high in Miami, which might expect to see around 19 cases at a 500-person school, based on its current infection rate. A 500-person school in Los Angeles, meanwhile, might see around four cases in the first week of reopening.
It's no wonder, then, that 60% of US parents support delaying school reopenings, according to a July survey. Teachers have also expressed concern about their own welfare: The American Federation of Teachers, the country's second-largest teachers' union, has threatened to strike in states that reopen classrooms without proper safety measures.
But President Donald Trump continues to push schools to reopen: "Much of our Country is doing very well," he tweeted on Monday. "Open the Schools!"
Most kids develop mild cases, but there are exceptions
Children represent around 5% of confirmed coronavirus infections in the US — the lowest of any age group, according to the Centers for Disease Control and Prevention. But pediatric coronavirus cases can be difficult to track, since they're often mild or asymptomatic.
One of the largest studies of children with the coronavirus to date, from the CDC, found that 18% of children tested positive but didn't report symptoms. Nearly three-quarters of the children in the study developed fever, cough, or shortness of breath, compared to 93% of adults. Out of more than 2,500 pediatric cases, only three patients died.
One reason for this could be that children have less mature ACE2 receptors — the enzymes that serve as ports of entry for the coronavirus — which could make it more difficult for the virus to infect a child's cells. The immune system also becomes more dysregulated as a person ages. So the pediatric immune system may simply be better at battling the coronavirus than the adult immune system.
But infants tend to develop more severe outcomes than older kids. More than 60% of infants with the coronavirus in the CDC study were hospitalized — the highest percentage among the pediatric age groups. Some scientists suspect that's because infants can have a greater inflammatory response than kids of other ages, so they're more likely to experience tissue damage as their bodies try to fight off the virus. Others suspect it's because infants have a less developed immune response than older children do.
While it's not clear yet how often kids transmit the virus to others, the CDC study found that children play at least some role in spreading the virus in the US. A study published last week found that US school closures may have prevented 1.37 million coronavirus cases in the span of just 26 days. The researchers estimated that school closures reduced the weekly rate of new cases in the US by 62%.
They also estimated that around 40,600 lives were saved over a 16-day period because of the closures.
School-aged kids may bring the virus home
Classrooms come with known coronavirus-transmission risks: They're often poorly ventilated indoor spaces and generally hold groups larger than 10.
Surveys conducted in Wuhan and Shanghai found that when schools were open, children had about three times as many contacts — either brief in-person conversations or physical interactions such as a handshake — as adults did. The researchers determined that closing schools reduced peak infections in those cities by up to 60%.
Gathering kids in classrooms could also increase the odds that students bring the virus home and pass it to older family members who are more likely to develop severe cases.
A recent study from South Korea found that school-aged children — ages 10 to 19 — were more likely to spread the coronavirus to their household contacts than any other age group. The study was conducted from January 20 to March 27, when schools in South Korea were closed.
On average, the results showed, 11.8% of people who shared a home with someone infected with the coronavirus got
Reopening schools may still be worth the risk
Closing schools may reduce transmission for two reasons: For one, keeping children home may create fewer opportunities for the virus to spread among them. It might also force parents to work from home or engage in fewer social activities, curbing close contact between them as well.
However, reopening schools didn't seem to drive up transmission in the Netherlands, Denmark, Finland, Belgium, Austria, Taiwan, or Singapore. European researchers also recently determined that there was "no clear association" between intergenerational relationships and the spread of the coronavirus.
Many public-health experts have suggested that sending kids to school might be worth the risk in the US.
Last week, Harvard professors wrote in the New England Journal of Medicine that reopening elementary schools should be "a top national priority." But the decision to reopen middle schools and high schools is more challenging, they added, given that susceptibility to the virus seems to increase with age.
The professors lamented the need to make these choices without more testing or contact tracing in place.
"It is tragic that the United States has chosen a path necessitating a trade-off between risks to educators and harms to students," they wrote. "This dilemma represents a social and policy failure, not a medical or scientific necessity."