Is there any good data on what impact opening schools[1] actually has on the spread of the virus?

Here in Sweden schools were kept open so that essential workers wouldn't have to stay home from work to take care of their children, and that decision doesn't seem to have impacted us negatively [2]. So it seems to me that, unless a child is in an at-risk group, there shouldn't be a negative impact from sending them to school.

The U.S. and Sweden are of course very different countries, so there might be some other factors at play that I haven't thought of.

[1] by schools I mean for kids up to the age of about 15, not universities and the like

[2] https://www.reuters.com/article/us-health-coronavirus-sweden...