To be honest, I can see how mandatory vaccinations would be an unethical law. I am not an anti-vaxxer, but I am not a big fan of forcing medical procedures on people either.
This is just an anti-vaccination web site. There are no other comparable "medical procedures" to vaccinations. Non-specialist scientists are not qualified to make "informed consent" decisions, no less uneducated, untrained parents. And the anti-vaccine movement seems focused on the measles vaccine at the moment, which is considered "optional" by the anti-science dummies, because many of them had measles as kids, and they think it's just "a bad cold with itchy spots". Unbelievable.
In most states you can be forced to allow medical treatment for your children, even if you are convinced that prayer is the better alternative, especially for infections where antibiotics are effective. In fact, depending on the state, your children can be placed in foster care if you refuse to let them be treated; constitutional protections for freedom of religion don't apply.
We already live with mandatory "procedures" that are more dangerous than vaccines. The use of seat belts and air bags in cars, to name two examples. I refuse to drive in cars without at least three-point seat belts (no 1965 Mustang driving or riding for me),but personally I hate the notion that airbags are mandatory because some people don't like to wear seat belts. Airbags are explosives. Or how about mandatory helmet laws?
And then there's smoking, banned pretty much everywhere in the US in public places now, but still allowed in private homes with children. Now there's an interesting moral question, where the science is obvious.