I am actually hoping that the risk for the teachers may not be as great as we feared. Sweden had their schools open during the entire pandemic and they have published a report on Covid per work category- based on lab confirmed Covid tests for the period 13march - 27 May. They showed number of cases, total number active in the profession and calculated a relative risk (RR) per profession.
The most risky professions in order were Taxi drivers, pizza makers, buss / train drivers with relative risks between 4.8 and 4.3 (how much more they were likely to catch Covid compared to other risk professions).
Schools had a special table and relative risk in related works (cleaners, teachers, nursery workers etc) were between 0.7 and 1.1.
I believe that the study excluded doctors etc (but not sure). Total number of cases analysed were 3188. There are obviously a huge number of other factors that influence things, but on a first glance, data from a country with open schools looks encouraging.
www.folkhalsomyndigheten.se/contentassets/5e248b82cc284971a1c5fd922e7770f8/forekomst-covid-19-olika-yrkesgrupper.pdf