Schools in more than 100 countries, including most in the U.S., are closed to aid in social distancing during the COVID-19 pandemic, but a new review study questions how much these closures will really help to reduce the disease's spread.
The authors, from University College London, reviewed 16 studies on the effect of school closures during coronavirus outbreaks, and concluded that "evidence to support national closure of schools to combat COVID-19 is very weak." In contrast, the harms of school closures, including high economic costs, are more clear-cut.
Policy makers should be aware of the uncertainty of evidence supporting school closures and may need to consider "other less disruptive social-distancing interventions in schools," the authors wrote in their paper, published online April 6 in the journal The Lancet Child & Adolescent Health. These might include keeping schools open only for the children of essential workers, staggering school start times and lunch breaks across different grades, increasing the space between students in classes or closing playgrounds.
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Most of the scientific data on the effects of school closures comes from studying seasonal or pandemic flu, and some of this research does show a benefit.
In particular, studies on flu suggest the effects of school closures may be greatest when viruses have a low transmissibility and infect children at higher rates than adults. (When a virus doesn't transmit that easily, school closures by themselves may reduce contact in the population enough to reduce the size of the epidemic.)
But this doesn't seem to be the case for the new coronavirus, SARS-CoV-2, which spreads more easily than the flu and causes less severe disease in children than it does in adults, the authors said. (Although it's unclear how big a role children play in spreading the new coronavirus, they may be less likely to spread the disease by coughing and sneezing since they tend to develop mild or asymptomatic cases, the authors said.)
In the new study, the authors reviewed research on the effects of school closures during the SARS outbreak of 2002, as well as research on school closures and social distancing in response to COVID-19. They looked at both studies published in peer-reviewed journals and studies that haven’t yet gone through that process but have been published on so-called preprint websites.
Studies on the SARS outbreak largely found that schools did not play a role in transmission of the virus, and so school closures didn't contribute to control of the outbreak, the authors said.
Recent studies on COVID-19 in China have found that a "package of social-distancing measures" that includes school closures were effective in reducing the size and peak of the outbreak there. But critically, these studies didn't separate the effects of school closures from other social-distancing measures, the authors said, so the true effect is unclear.
The authors found only one study that looked at the effect of school closures separate from other social-distancing measures. This study, which modeled the effect in the U.K. population, suggested that school closures by themselves were predicted to reduce COVID-19 deaths by only 2% to 4%, which was much lower than the effect of other measures, such as isolating infected cases.
'Urgent need' for research
There is an "urgent need" to better study the effects of school closures during COVID-19, as well as how countries that have already shut schools and offices can "safely return students to education and parents to work," the authors said.
More studies are also needed to figure out how big of a role children play in transmitting COVID-19, they said.
"Education is one of the strongest predictors of the health and the wealth of a country's future workers, and the impact of long-term school closure on educational outcomes, future earnings, the health of young people and future national productivity has not been quantified," they concluded.
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Originally published on Live Science.