Kevin Drum has a round-up of the effect of school closures on pandemic spread. Everybody agrees that people under 25 face very little chance of death or even hospitalization – unless they are immuno-compromised in some way. So if we re-opened the schools more children would die in bus accidents than from the virus.
On the other hand, children do get infected and can spread the infection to others, especially others they live with. e.g., their parents.
On the third hand, if parents have to stay home to care for their children, that may have some effect on rates, although there is no agreement about what this effect might be.
Drum thinks that right now the evidence is that we should re-open most schools. I think I agree, assuming we keep in place some kind of distance learning for kids with severe asthma etc.
Some US colleges are going to an abbreviated Fall semester, opening at the normal time but then not coming back after Thanksgiving. This is for two reasons: first, because they are betting that this is a seasonal virus, and second, because colleges always see a bad wave of colds and flu after students go home for Thanksgiving and then come back bringing a nationwide stew of viruses.