Open schools or school re-opening: under which conditions has it jeopardized epidemic control in 2020-2021
The disparity of evidence brings us to the second key unknown we had previously identified: what have we learnt about the role that transmission among children and adolescents has played at the population level? Epidemiological data coming from countries that have prioritized continuous in-presence schooling especially for the younger age groups, such as Iceland, France, Norway, Sweden, Estonia, Denmark, and studies monitoring the effect of re-opening of schools in countries that had previously kept them closed, such as Italy, Germany, USA, UK, can be greatly informative to understand the real-life epidemiological consequences of leaving complete school closure to be a last resort in controlling the COVID-19 pandemic. Although multiple contextual variables could be factored out to account for any incompatibilities in this large pool of evidence, three appear to be of key importance: the age of the school-children involved, the background prevalence, and the infection control measures initiated concurrently with opened educational facilities.