As an anarchist I do not accept that the State (at any level) has the right to oblige parents to vaccinate their children. However, my kind of mutual aid anarchism does not mean a complete lack of rules.
The sharing of scarce resources often requires some form of agreed reciprocity from all who gain from the sharing — an agreement to follow the rules of the club, if you like, as the cost of membership in the club. It follows from that that school boards, managing the distribution of education by school-board paid teachers and facilities, a scare resource, as delegates from the parents and children assembling, can set a rule insisting that children be vaccinated as a prerequisite to delivery of the resource.
They can set such a rule and they should do so for the protection of the community as a whole.
Parents who choose not to follow the rule should be left to make their own arrangements for the education of their children.