School Closure During the Coronavirus Disease 2019 (COVID-19) Pandemic

An Effective Intervention at the Global Level?In most countries, attempts to reduce severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) circulation and new coronavirus disease 2019 (COVID-19) development have been mainly based on restrictive measures, including the avoidance of social interactions, the prohibition of movements within the national territory, and the closureofallnonessentialactivities,includingschools.While the closure of factories and the avoidance of other social interaction together with proper hand washing remain the best measures to reduce the total burden of COVID-19, the usefulness of school closure can be debated.It is highly likely that the most important reason leadinggovernmentstocloseschoolswastheevidencethatthe early introduction of this restrictive measure had been effective in reducing influenza incidence rates and related clinical,social,andeconomicproblemsduringbothseasonal and pandemic influenza outbreaks. 1However, it is not at all certain that the same advantages can be expected in the case of the COVID-19 pandemic.It is even possible that schoolclosuremayhavenegativeeffectsandleadtogreater medical, economic, and social problems.Modeling studies seem to indicate that school closure can be significantly effective for infection control only when the outbreaks are due to viruses with low transmissibility and attack rates are higher in children than in adults.This applies to influenza viruses and influenza infection but does not seem valid for coronaviruses,includingSARS-CoV-2,whichhavedifferent transmission dynamics, or for COVID-19, which affects mainlyadultsandelderlyindividuals.Ithasbeencalculated that the expected number of cases directly generated by 1 case of SARS-CoV-2 infection (R 0 ) is high and not lower than 2.5. 2 Moreover, children younger than 10 years account for only 1% of COVID-19 cases, 3 and although a certain number of them can experience an asymptomatic infection, the total number of children with SARS-CoV-2 infection seems lower than expected.Although no official data are available, to our knowledge, on the effectiveness of school closure during the COVID-19 epidemic, the poor relevance of this restrictive measure seems confirmed by the evidence that in Taiwan, the spread of COVID-19 was minimized without widespread planned school closures. 4n the other hand, using UK population and school data together with data on SARS-CoV-2 transmission dynamics calculated in the early COVID-19 pandemic in China, it was predicted that school closure would be insufficient to mitigatethepandemic.Finally,thepooreffectofschoolclosure during coronavirus epidemics has already been evidenced in some studies carried out during the SARS epidemic.In China,itwasfoundthatschoolclosurefor2monthswasnot significantlyeffectivefordiseasepreventionmainlybecause of the very low incidence of symptomatic disease among school-aged children. 5Moreover, in Taiwan, it was evidenced that the risk of transmission of infection among