Enric Álvarez at the Universitat Politècnica de Catalunya looked at different regions within Spain for his recent co-authored working paper. Spain's second wave of coronavirus cases started before the school year began in September. Still, cases in one region dropped three weeks after schools reopened, while others continued rising at the same rate as before, and one stayed flat.
Nowhere, the research found, was there a spike that coincided with reopening: "What we found is that the school [being opened] makes absolutely no difference," Álvarez told NPR.
Spain does extensive contact tracing, so Álvarez was also able to analyze how much schools are contributing to the spread of the coronavirus. Álvarez said his research suggests the answer is: not much. He found that, for all the students and staff who tested positive, 87% of them did not infect anyone else at the school. They were single cases.
"We are not sure that the environments of the schools may not have a small and systematic effect," said Álvarez, "But it's pretty clear that they don't have very major epidemic-changing effects, at least in Spain, with the measures that are being taken in Spain."
These safety measures include mask-wearing for all children older than 6, ventilation, keeping students in small groups or "bubbles," and social distancing of 1.5 meters — slightly less than the recommended 6 feet in the United States. When a case is detected, the entire "bubble" is sent home for quarantine.
Insights for Education is a foundation that advises education ministries around the globe. For their report, which was not peer reviewed, they analyzed school reopening dates and coronavirus trends from February through the end of September across 191 countries.
"There is no consistent pattern," said Dr. Randa Grob-Zakhary, who heads the organization. "It's not that closing schools leads to a decrease in cases, or that opening schools leads to a surge in cases."
Some countries, such as Thailand and South Africa, fully opened when cases were low, with no apparent impact on transmission. Others, such as Vietnam and Gambia, had cases rising during summer break, yet those rates actually dropped after schools reopened. Japan, too, saw cases rise, and then fall again, all while schools were fully reopened. But the United Kingdom saw a strong upward trend that started around the time of reopening schools.
"We're not saying at all that schools have nothing to do with cases," Grob-Zakhary said. What the data suggests instead is that opening schools does not inevitably lead to increased case numbers.
What about the U.S.?
On Oct. 14, the Infectious Diseases Society of America gave a briefing on safe school reopenings. Bottom line? "The data so far are not indicating that schools are a superspreader site," said Dr. Preeti Malani, an infectious disease specialist at the University of Michigan's medical school.
One place in the U.S. where systematic data gathering is happening — Utah — seems to echo the conclusions drawn by the new international studies. Utah's state COVID database clearly reports school-associated cases by district. And while coronavirus spread is relatively high in the state, State Superintendent of Public Instruction Sydnee Dickson believes that schools are not, for the most part, driving spread.
"Where you see cases on the rise in a neighborhood, in a county, we see that tend to be reflected in a school," Dickson said. "[But] we're not seeing spread by virtue of being in school together."
Tom Hudachko of the state's health department said that after both colleges and schools reopened in early September, there was a rise in cases among the 15-24 age group. But with targeted public health messaging those cases have started to come down.
For the most part, Hudachko said, K-12 school clusters have been concentrated at high schools. "We have had some outbreaks in middle schools. They've been far less frequent. And elementary school numbers seem to be one-offs here and there."
And these clusters — including one large reported outbreak with at least 90 cases — have largely been traced to informal social gatherings in homes, not to classrooms. (Álvarez, in Spain, also said that clusters among young people there have been traced to social gatherings, including rooftop and beach parties).
Few states are reporting school-related data as clearly as Utah. And that's a shame, said Buntin at Vanderbilt. "One might argue that we're running really a massive national experiment right now in schools," Buntin said, "and we're not collecting uniform data."
The largest centralized effort at such data collection in the United States — the unofficial, crowdsourced COVID-19 School Response Dashboard — has gotten a lot of publicity. But it is self-reported, not a representative sample of schools.
Buntin and other experts said it's likely that the dashboard is biased toward schools that are doing an exemplary job of following safety precautions and are organized enough to share their results. Also, the dashboard doesn't yet offer the ability to compare coronavirus cases reported at schools with local case rates.
In the absence of data, there are scary and tragic anecdotes of teachers around the country dying of COVID-19. But it's hard to extrapolate from these incidents. It's not immediately clear whether the educators contracted the virus at school, whether they are part of school-based clusters, or what safety precautions were or were not followed by the schools in question.
A recent study from Yale University could potentially shed some light on these questions. It tracked 57,000 childcare workers, located in all 50 states, Washington, D.C., and Puerto Rico, for the first three months of the pandemic in the United States. About half continued caring for very young children, such as the children of essential workers, while the other half stayed home. The study found no difference in the rate of coronavirus infections between the two groups, after accounting for demographic factors.
Walter Gilliam, lead author of the study and a professor of psychology at the Yale Child Study Center, cautioned that it's difficult to generalize this report to a K-12 schools setting, because the children were mostly under the age of 6 and kept in very small groups — and, he said, the childcare workers were trained in health and safety and reported following strict protocols around disinfection. However, he said, "I think it would be great to do this study with school teachers and see what we can find out."
Risk and benefit
When you add up what we know and even what we still don't know, some doctors and public health advocates said there are powerful arguments for in-person schooling wherever possible, particularly for younger students and those with special needs.
"Children under the age of 10 generally are at quite low risk of acquiring symptomatic disease," from the coronavirus, said Dr. Rainu Kaushal of Weill Cornell Medical Center. And they rarely transmit it either. It's a happy coincidence, Kaushal and others said, that the youngest children face lower risk and are also the ones who have the hardest time with virtual learning.
"I would like to see the students, especially the younger students, get back," said Malani at the University of Michigan. "I feel more encouraged that that can happen in a safe and thoughtful way."
Chicago Public Schools, one of the largest districts in the country, seemed to take that guidance into consideration when it announced recently a phased reopening starting with pre-K and special education.
Kaushal said it's important to keep in mind that Black, Latinx and Native American communities are much more severely affected by COVID-19. And that many of the "children that are at the severest risk of disease, are also at the severest risk of not having a school open, whether it be for food security, adult time, security, losing the time to learn or losing the skills that they have acquired over the last year or so."