WWhen state officials decided whether to close their schools in March, the evidence they had to work with was scant. They knew that children easily catch and transmit influenza, and that school vacations and closings have helped curb its spread. But they weren’t sure if the same was true for Covid-19.
Now, a study published Wednesday in the Journal of the American Medical Association shows that closing all schools in a state was associated with a drastic decrease in both Covid-19 cases and deaths. And the point at which officials made that call was important: those states that adopted the policy while few people tested positive saw a more correlated case curve.
“It is a nice study. It’s clear that, coinciding with the closing of schools, the numbers improved, “said Helen Boucher, chief of the division of geographic medicine and infectious diseases at Tufts Medical Center, who was not involved in the investigation. But she noted that we have to be careful when drawing too broad conclusions from a single radical closure strategy: “The closure of the school did not occur in a vacuum.”
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It is also unclear how likely it is that children of different ages will catch and transmit the virus, making it difficult to discover the reasons why school closings could have helped change the outbreak.
“It is very possible, and likely, that people will change their behavior because they thought, ‘Oh my gosh, this new virus exists and it’s so scary that schools will close,'” said pediatrician Katherine Auger, associate president of Cincinnati results. Children’s. Hospital Medical Center, and the first author of the new article.
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“One thing we cannot decipher is how much of the effect was related to the spread of the virus within schools and the biggest change in the community because now parents are not going to work,” he added.
The findings come amid a furor over school reopens. This spring, the Centers for Disease Control and Prevention released guidelines on preventing viral transmission within schools, recommending that students be physically separated, by putting desks 6 feet away, for example. For some schools, that seemed impossible, given the number of children enrolled and the architecture of the classrooms. That meant that at least some teaching would be done online, contradicting the president’s optimistic, and for many risky, public health experts ideas about the reopening.
After both Trump and Vice President Mike Pence criticized the guidelines and encouraged schools to reopen entirely, the CDC released revised guidelines, raising fears that federal public health experts would collapse under political pressure.
The new study shows no cause and effect, just an association between school closings and case counts in one area. The authors cautioned that it also cannot provide a general recipe for fall.
“Our study took place at a time when schools were not doing things like masking,” explained Auger. “It is really impossible to project the old form of schools into the future of schools, assuming they will follow the lead of the experts.”
For her, the work supports the “flexible and agile” approach endorsed by the American Academy of Pediatrics. Having children physically present in schools not only stimulates academic learning and the essential cognitive and emotional development that comes from social interaction, the organization said. It also enables them to receive a host of services, from free meals to adult eyes that can detect signs of abuse at home.
But those benefits must be weighed against the risks of Covid-19 to children, parents, grandparents, and teachers, a threat that must be controlled with rapid tests that much of the country cannot provide.
In the new study, Auger and his team compared reality, in which all 50 states closed schools in March, to a computer model in which everything else remained the same while schools remained open. They calculated the time it would take to transmit infections acquired in schools, and for these patients to report to hospitals and for a certain fraction of them to die.
His projection found that if the schools had remained open, there could be approximately 424 more coronavirus infections and 13 more deaths per 100,000 residents over the course of 26 days.
Extrapolating that to the American population, and the country could have seen as many as 1.37 million more cases and 40,600 more deaths, explained Samir Shah, director of medicine at the hospital at Cincinnati Children’s Hospital Medical Center and one of the authors of the Article.
“These numbers seem ridiculously high and it’s mind-boggling to think these numbers are just … in the first few weeks,” Shah said. “That’s crazy”. However, he cautioned that those numbers should be taken with a grain of salt. Although its statistical model tries to identify the impact of open or closed schools, the method cannot establish any type of causal relationship.
The authors realized that their estimate of how long it might take for a detected infection in a school to become a symptomatic case of Covid-19 could be off, and they wondered if that could influence their results. However, when those time intervals changed, they still found a significant correlation between school closings and decreased workload and mortality.
For Steffanie Strathdee, associate dean of global health at the University of California, San Diego, that’s what made this study compelling. “This study took imperfect data but did a very elegant analysis,” he said. “If we are wrong, what is the other extreme, would it change the results? If these children infected the parents, but it took a little longer or a little shorter, then what?
The bottom line, he said, was that strategies like school closings seem to make a difference when it comes to Covid-19 risks.
Auger’s team also analyzed whether the timing of school closings correlated with a change in cases and deaths. “The states that closed schools before their Covid numbers were high had the greatest effect,” he said.
While children appear to be less likely to become ill than adults, there is evidence that schools may be important sites of coronavirus transmission. Younger children appear less likely to transmit the virus than preteens and teens, although more research is needed to fully understand the various risks.
Shah, meanwhile, warned that people reading the study should not forget the risks of disruptions to education. “We can quantify Covid’s risk. It is much more difficult to quantify the risk of being absent from school for an extended period of time, “she said.
He and Auger both emphasized the importance of tailoring strategies to the needs and risks of coronavirus within each family and community, and that better and faster testing would allow for a safer strategy for back to school. “It is a real challenge, and I think our study is a very important piece of the puzzle in how we think about this,” Shah said.