There is some initial evidence that teacher unions may influence school openings. From the abstract: Using data on the reopening decisions of 835 public school

There is some initial evidence that teacher unions may influence school openings. From the abstract: Using data on the reopening decisions of 835 public school districts in the United States, we find that school districts in locations with stronger teachers’ unions are less likely to reopen in person even after we control semi-parametrically for differences in local demographic characteristics. These results are robust to four measures of union strength, various potential confounding characteristics, and a further disaggregation to the county level. We also do not find evidence to suggest that measures of COVID-19 risk are correlated with school reopening decisions. http://dx.doi.org/10.2139/ssrn.3684867 http://dx.doi.org/10.2139/ssrn.3684867