@Oaktree55 quoted from The Lancet.
School closure was widely adopted previously to control influenza outbreaks and pandemics, and was shown to reduce and delay peaks of epidemics.16, 17 For SARS-CoV-2, the role of children in its transmission is still unclear. A modelling study from China showed that school closure alone could not interrupt transmission, but it could potentially reduce peak incidence by 40–60% and delay the epidemic of COVID-19.18 In this study, we showed that closing schools alone could decrease transmission by 15% (R ratio 0·85, 95% CI 0·66–1·10) on day 28 and reopening schools could increase transmission by 24% (1·24, 1·00–1·52) on day 28. It should be acknowledged that in our analysis, we were unable to account for different precautions regarding school reopening that were adopted by some countries, such as physical distancing within classrooms (eg, limiting class sizes and placing transparent dividers between students) and outside classrooms (eg, physical distancing during meal times, recreation, and transportation), enhanced hygiene (eg, routine deep cleaning and personal handwashing and face masks), and others (eg, thermal temperature checks on arrival).19, 20 Such precautions are imperative for safer school reopening. A COVID-19 outbreak was reported in a high school in Israel 10 days after its reopening; students were in crowded classrooms and were not instructed to wear face masks due to high temperatures.21 In addition, it should be noted that we did not consider the normal school holidays in some countries. We were also unable to assess the effect of reopening different levels of school (eg, elementary vs middle schools) since the effect might differ by finer age bands within school-age children and adolescents.21, 22 A report found that children younger than 5 years with mild to moderate COVID-19 had high viral loads in their nasopharynx compared with older children and adults, and thus could potentially be important drivers of transmission in the general population.23