What should a schoolteacher do then, die? I'm not going to ask them to do that.
They should be put in one of the top priority categories for vaccination, and THEN we can expect them to go in classrooms (but we shouldn't be doing that anyway unless all kids are also vaccinated - otherwise they will keep the virus in circulation. They tend to have extremely mild or completely asymptomatic cases, but they DO catch it and spread it further)
Feudal traditions aside, no one has the right to draw an income from a position where they are not doing the job. So, if teachers don't want to teach, then they can find another occupation which they are comfortable doing.
Why not the same thing a grocery clerk is expected to do? Or do you not consider primary education to be “essential” ?
Also, do you know what else has unknown long-term effects in children?