In most German schools, face masks are mandatory at least to some extent. Moreover, all schoolchildren and the few unvaccinated teachers are tested for COVID-19 up to three times a week. A new IZA discussion paper by Ingo E. Isphording, Marc Diederichs, Reyn van Ewijk and Nico Pestel investigates how school re-openings after the summer break have affected the spread of the pandemic.
Since summer holidays are staggered across German states, the researchers were able to compare states where schools opened again after the summer break with states where schools were still closed. To isolate the effect of school re-openings, they controlled for changes in mobility as people increasingly commuted to work again.
The analysis shows that open schools did not accelerate COVID-19 infection rates. While cases among 5 to 14-year-olds did increase temporarily due to positive tests of children who had not been tested during the holidays, there was no longer-run effect on COVID-19 cases in this age group, nor among people aged 60 and over. Most remarkably, infections among 15 to 59-year-olds remained even lower than they would have been if the schools had remained closed.
These findings indicate that mandatory testing in schools promotes the early detection and quarantining of infected children, which contributes to curbing the pandemic also outside of schools. Since COVID-19 cases among children are often asymptomatic yet infectious, keeping schools open with mandatory testing helps identify infected children and prevent them from spreading the disease.
The authors conclude that schools – at least in the German school system where testing, mask-wearing and a set of additional hygiene measures are in place – do not pose a considerable infection risk to children, while at the same time they can help stem the pandemic.