I have a relative (not a teacher) who can no longer have vaccines due to Guillain-Barré and another friend's relative currently intubated in the hospital with a single J&J shot (no booster unfortunately.)
Kids while not very vulnerable seem to be a carrier into the home.
I don't believe mandated student vaccines is enough for these people (or for the parents of vulnerable students). Instead, we have to do the hard work of allowing appropriate accommodations for high risk individuals. Unfortunately, vaccine or not, much of the responsibility for derisking will inevitably fall to vulnerable individuals themselves, ideally with as much societal support and backing as possible (e.g., plexiglass enclosures for vulnerable employees? I'm not the expert here).
Nothing else we've done so far seems to move the needle much. The stakes aren't personally high enough for everyone else in society to maintain the necessary vigilance for years on end.