This is not just a civil liberties issue. It is a medical autonomy issue.
The moment that the law becomes involved in medical decisions of patients for anything besides emergency cases such as a quarantine, the right to informed consent goes out the window.
People have the right to choose what the majority may view, with however much ample justification, as the objectively inferior treatment course.
The issue is complicated somewhat when a child is being subjected to a parent's ignorance or ideological issues.
However, civil actions should reasonably be filed against those who parents whos children get others sick.