Vaccination is like catastrophic insurance coverage.if you have it when catastrophe/infection hits you will survive.
If one chooses to not vaccinate against smallpox and the child dies from it.This would be a catastrophe allowed to happen.Is this just?Is it an acceptable risk?
Life is and all things are risky to some degree.Does society have a say in this risk management technological?
And then there is the zonifiable alternative which is nothing at all.