"If your child was infected with measles and you knowingly sent him/her out in public while still contagious then yes, I do believe you should be held responsible if others were infected as a result. "
I really agree that parents who knowingly allow their child to potentially infect others, without their consent, are morally responsible here, but I'm interested in how this could play out legally.
I'm in the UK not the US, but I think our legal systems are pretty similar-do you guys not have laws about transmission of infectious diseases? I'm not up on this law but I'd guess prosecution would not need to show intent, only negligence, ie lack of care. To my mind, to take a child known to be suffering from measles out and about would constitute negligence with regard to exposing others to an infectious disease. It wouldn't much matter why a child had measles-whether through having refused vaccination, having had the vaccine fail, or being immunosuppressed and so unable to recive the vaccination.
Its an interesting question though as to whether parents who refused vaccination could be prosecuted or sued. What's the period when these diseases are infectious? Is it before the appearance of symptoms? If so, actually I can really see theoretically how not vaccinating could open a parent up to either a civil or a criminal action for negligence.
And actually, this isn't something that needs to happen on a state level. Certainly in the UK, afaik, it would be technically possible to bring a civil action for negligence against parents who, through not having taken what the court considered sufficient care, allowed their child to infect another, with financially measurable consequences. For a civil case, the standard of proof would be the balance of probabilities (its not unknown for civil cases to be brought after criminal prosecutions fail, just because the burden of proof is lower). I think a criminal prosecution would really struggle, and would ultimately fail at having to prove beyond reasonable doubt that the disease had been transmitted by child x
OTOH the worst that can happen after being found guilty in the civil courts is that you have to pay up to the person who brought the case against you. And tbh, it costs a lot of money to go through the civil courts, especially, I'm guessing, in America. AND individuals are seldom targeted because what's the point? They don't have usually have that much money, so the most likely outcome if they get a bill for $1 million is that they may end up bankrupt. Which may be emotionally satisfying for the party bringing the case, but long term who wins?