A number of factors may cast doubts on the real usefulness of school to limit COVID-19 pandemic. Maintaining children at home in order to reduce the risk of them becoming infected and developing COVID-19 can be considered of poor clinical importance as children, when infected by SARS-CoV-2, generally remain asymptomatic or suffer from a mild disease that does not require hospital admission [
3].
Moreover, school closure during the SARS and MERS epidemics was poorly effective in reducing morbidity and mortality, as was the experience of Taiwan, one of the very few countries where schools remained open during the first wave of the COVID-19 pandemic [
4]. Studies that have monitored the epidemiology of SARS-CoV-2 before and after school re-opening when the first COVID-19 wave was considered over did not definitively solve the problem of the importance of school closure. In some countries, re-opening was not associated with any significant variations in COVID-19 incidence or related deaths [
5,
6]. In contrast, in a study carried out in the USA, closure was associated with a significant reduction in SARS-CoV-2 circulation and related clinical problems [
7]. However, it cannot be excluded that this positive effect was not strictly related to the school closure per se but could depend on several other concomitant factors, including the adherence of school workers and parents to the recommended preventive measures such as mask use, social distancing and frequent hand washing. Use of cloth face coverings in the U.S. population varied significantly during COVID-19 pandemic. Immediately after the first national recommendations were made, only approximately 60% of the enrolled adults reported the use of face masks [
8]. On the contrary, 1 month later, in May, the prevalence of mask use increased to 76.4%. On the other hand, adherence to social distancing among people also seemed to be suboptimal. Finally, as most of the American people interviewed responded that they repeatedly wash their hands during the day to prevent COVID-19, a nonmarginal proportion of them (19%) do not regularly follow recommendations [
9]. A further factor that may suggest that schools per se play a minor role in favouring COVID-19 diffusion is the evidence that, when general measures for infectious disease transmission were carefully followed, risk of transmission of SARS-CoV-2 from child to child during summer camps was several times lower than that of the general population.
Although reports of outbreaks of COVID-19 among children in schools and summer camps have been made [
10], several studies have shown that children in educational setting and attending summer camps do not contribute significantly to COVID-19 diffusion [
11]. On the other hand, previous experience has shown that school closure is systematically associated with the development of problems involving students, teachers and parents, particularly among populations with poor resources [
2]. In children, opportunities for growth and development were dramatically reduced. Social isolation could lead to psychological limitations of much longer duration than the school closure itself. In some cases, nutrition could be compromised, as many children rely on free or discounted meals provided at schools. Furthermore, connections with students were frequently difficult, particularly when distance learning was not previously experienced and some parents had economic difficulties in activating e-learning.
The available experience highlights that in presence of an efficient contact tracing flexible protocols permit attendance of schools by children and adolescents without a significant increase in COVID-related morbidity and mortality.