Important data point: Israel reopened schools May 17. Since then at least 1,335 students and 691 staff have become infected and it appears to have fueled a resurgence of COVID-19 outbreaks. wsj.com/articles/israe…
Epidemiological surveys showed that after Israel opened its school system w/o restrictions 5/17, a spike in infections occurred among the country’s youth that later spread to the general population. Schools were 2nd highest known place of infection outside people’s communities. 
Looking back, a lot of this appears to have been about lack of seriousness among many schools, students, and families about wearing masks and minimizing crowding indoors.
