COVID-19: we need randomised trials of school closures.

One of the most controversial and radical societal interventions to curb the COVID-19 epidemic is the closing of schools and nurseries. There seems to be broad agreement that the effect this will have on the spread of the virus is uncertain, and the negative implications are obvious. Economic costs are high when parents must stay at home to take care of their children and cannot work1 for children, and social isolation and the impact on learning are key concerns, especially if school closures are long-lasting. Empirical evidence on the effect of school closures stems from observations during influenza epidemics.2 3 Systematic reviews have not identified any randomised trials, but observational data indicate that school closures reduce the spread of influenza.2 3 However, while children play an important role in transmitting influenza viruses, the available data seem to show that their role may be smaller in the transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2): relatively few children have tested positive, and children are mildly affected compared to adults,4 5 which is likely to mean that they are also less infectious.6 The facts that there are few documented cases of children as sources of transmission and no reports of outbreaks among children in schools or nurseries support the inference that children play a smaller role in the spread of SARS-CoV-2 than influenza. From a ‘better safe than …