I thought I’d offer some thoughts on an issue that is starting to get attention: Should parents who choose not to vaccinate their children against standard childhood illnesses (measles, mumps, whooping cough) be held liable if their child makes someone else’s child sick with one of these diseases? For purposes of this discussion, let’s make two assumptions. First, the choice not to vaccinate was not made for religious reasons. (That presents a more complex problem.) Second, there is no contributory negligence (in those jurisdictions) or significant comparative negligence (in jurisdictions that bar recovery when plaintiff is more negligent than defendant) by the parents of the sick child.
The most plausible factual scenario goes something like this. Plaintiff’s child is too young to be vaccinated fully against a disease or cannot be vaccinated for some unavoidable reason. This child is exposed to defendant’s child, who is old enough for full vaccination but was not given vaccine and is a host for the disease. The choice not to give vaccine is made because of concern about the risks that vaccines pose, the belief that they increase the chance of becoming autistic, or some other non-religious reason.Now the question that will generate the most controversy is whether parents are negligent for not vaccinating their child under these circumstances. I want, though, to focus on how the causation issue would play out. How would a plaintiff show that exposure to defendant’s child was the cause of the disease?
Here we face an ironic problem. One thought behind vaccination is “herd protection.” The idea is that if everyone in a given population who can be inoculated is inoculated then it is far less likely that those who cannot get vaccinated will get sick. (You can argue that those who are not vaccinating are free riding on those who do.) When it comes to legal liability, though, herd protection favors those who choose not to vaccinate. The more children there are like that, the harder it will be for a plaintiff to show but-for cause with respect to any individual child.
How should courts deal with that? Is the answer that these claims should be viable when a plaintiff can prove that only one child could have exposed his or her child to measles? Or should we shift the burden of proof to defendants? Is this a Summers v. Tice situation (at least if we could narrow culpability to a few children) That question depends, in part, on how bad we think not vaccinating is. Generally the more egregious the wrong, the more likely we are to extend the scope of causation to hold the wrongdoer liable.
Anyway, I’m sure this will be litigated at some point, and it’s a topic to watch.