There is a group that advocates against the use of vaccines in children. I will have to find the link. Each state has different requirements under which you can claim exemption, be it religious or another allowable reason. They also advise to write up a letter for which you will ask for their signature that says something like they take full responsibility for any and all adverse reactions to the vaccine that your child may encounter. Any sane person would never sign such a thing, knowing full well the legal implications of signing it.