Assault and battery, probably. And then you'd be the defendant in a civil law suit, which even if you win will require time and legal fees.
A different solution: unless your child has a medical reason (allergy to one of the ingredients in the vaccine, compromised immune system, or the like -- "I don't want it" doesn't count) not to have the vaccine, the child won't be permitted in public school. This includes the classroom, extracurricular activities, etc. The parents will have to arrange (and pay) for alternate schooling, to protect the general school population. The principals, superintendents, and school boards can even describe it as "We're thinking of the children."