Pre-school teachers here have not had higher cases either, as far as I can tell. Many have stayed open. No outbreaks reported that I know of.
We're seeing cases in summer camps (mostly the stay-over, sleep-in-a-cabin type). At age 12, the symptoms in kids here are more significant and all of our deaths, as far as I know are in the over 13 group. We don't know how teachers will fare. Classroom sizes here in California, if not lowered by policy, can be 35 kids in a fairly small space (sometimes without windows, just a door that opens).
Community transmission seems the most likely vector for most teachers in the data we have (not transmission from kids). High school teachers are more likely to get CoVid than are primary grade teachers (and middle schools are in the middle). It appears that teaching 17-18 year olds is less safe and that more of the teenagers get the illness.
Our nation is less healthy than Sweden, sadly. Lots more obesity and diabetes, high blood pressure meds are in use in kids as young as their teens. The data are actually pretty awful:
High Blood Pressure in Kids and Teens | cdc.gov.
We also don't know yet whether those with hypertension are more susceptible to CoVid and its symptoms to begin with. We may be about to find out, given that some states and counties seem determined to have school as usual. But there is evidence that hypertension seems to make CoVid worse, when a person gets it.
I'm guessing that hypertension and diabetes are much less common in the teen population of Sweden.
