The Volokh Conspiracy

Mostly law professors | Sometimes contrarian | Often libertarian | Always independent


Libertarianism and Communicable Disease


In a recent post, I mentioned that I tentatively support UC's new requirement that all students, faculty, and staff get vaccinated against the flu. (I say tentatively because it's possible that the medical benefits aren't great enough.) My reasoning there specifically focused on the government's propriety role there: I think it's generally legitimate for institutions (government or otherwise) to protect their clients (including students) and employees from the risk of harm—including inadvertent harm—inflicted by other clients and employees.

But I also think that it would be morally permissible for the government to require various vaccines for everybody, and not just for its employees or students. Again, it might be that the costs of some particular vaccine mandate would exceed the benefits; and we should count cost to liberty in some measure in this analysis. But I don't think that vaccinations are categorically precluded on libertarian grounds, or in particular the Millian "free to do what I please so long as I don't harm others" principle. Let me quickly lay out my thinking.

It is a sad fact of biology that we can spread communicable diseases without any conscious decision on our parts, even without knowing that we are infected. Any time we do this, we are causing physical harm to someone else, and indirectly causing physical harm to many others; and we do that without choosing to cause such harm.

An analogy might be guns. Libertarians generally frown on gun bans, and instead seek to ban misuse of guns. People who use guns properly, the theory goes, should be free to keep doing that; only those who choose to misuse them (to kill or to shoot recklessly or the like) should be punished. Likewise with alcohol and the like.

But say that you had a gun that had a 1% chance of just randomly shooting someone—or perhaps a 1% chance of leaking a deadly poison into the air around you—even when that wasn't at all your desire; and there was a procedure that could be performed on your gun that would pretty safely eliminate or at least sharply reduce that chance. It seems to me that it would be reasonable to require you to have your gun treated with that procedure, to prevent you from inadvertently inflicting such physical harm to others. Likewise when the dangerous weapon (or the poison-leaking device) is your body.

Some libertarians respond that the right approach is to allow people to choose whether to be vaccinated, but to allow others to exclude the non-vaccinated from spaces that those others control. That might cut in favor of private universities or even public ones mandating vaccination, but might still forbid the government from imposing such mandates. And perhaps such an approach might work in a libertarian society where all property was private, and policed effectively for who is coming on the property and who isn't.

But in our society, for better or worse, people routinely go onto shared government-controlled property, and are generally allowed to go on much private property (such as businesses open to the public) without any effective screening of such visitors. We need a second-best libertarian analysis that works for this society, and I think it makes sense to allow compulsory vaccinations, by counting exposure (even inadvertent) to communicable disease as an unconsented-to harm that people can be prevented from inflicting on others.

More concretely, let's consider a topic that was in the news some years ago (when I first blogged a version of this post): immunizations against sexually transmitted diseases, such as HPV. I'll start with that, and turn to flu immunizations at the end of the post.

Say Alan has sex with Betty, who then has sex with Carl, who then has sex with Denise; say Alan is infected with HPV, and each sexual act would (absent immunization) spread HPV; and say Betty isn't immunized against HPV. Betty's failure to get immunized would lead to her unwittingly spreading the virus, which ends up hurting Denise. Betty hasn't intentionally harmed Denise, but she has harmed her—you might categorize the harm as negligent (in that it flows from negligent failure to get immunized) or not, but it is indeed the infliction of harm.

Now it's true that the harm also flowed from Denise's voluntary decision to have sex with Carl. But it's hard to see why this should excuse the harm caused by Betty, any more than Denise's voluntary decision to get on the road excuses the harm that someone imposes on Denise by crashing into her with a car (or, if you prefer, that Betty imposes on Denise by crashing into Carl's car, which then crashes into Denise's).

Even if you think that some people's having many sexual partners should affect the analysis, remember that HPV can be spread even among people who are about as sexually constrained as can be expected. The Alan-Betty-Carl-Denise connection can happen even if Betty was a virgin when she married Alan; if she then didn't have sex with Carl until she married him (assume Alan had died, or had left Betty); and if Denise was a virgin when she married Carl (again, assume Betty had died, or had left Carl).

This specific scenario might be rare—but lots of other scenarios in which people had led fairly safe lives, but find themselves getting HPV, are also quite plausible. And more broadly, even if people are leading somewhat riskier lives than this, participating in infecting them with a disease may still be quite rightly seen as harming them, despite their own role in choosing risky behavior.

Of course, if HPV immunization were 100% reliable, and 100% available, then this analysis wouldn't apply with quite the same strength: Presumably any person who remains at risk of HPV infection would be at risk because of her own refusal to get the vaccine. Yet some people don't get the vaccine, possibly because they can't afford it; some can't get it because they're in the small but significant group of people for whom the vaccine would be unsafe; for some classes of people, the vaccine hasn't been tested (for instance, for people in their age group); and for at least some vaccines, the vaccine may be far from 100% effective for any individual recipient.

So I think that a libertarian may reasonably conclude, I think, that refusing to get immunized is wrongful behavior. Such refusal may lead to one's becoming a vehicle for transmitting a dangerous and sometimes deadly disease to third parties, and thus harming those third parties (in a way that an "assumption of risk" argument would not excuse). And while a vaccine will step in before the harm is inflicted, rather than as punishment for inflicting harm, it doesn't make sense to take a punishment model: Again, the harm of spreading communicable disease generally isn't inflicted through deliberate choice to do something unusually dangerous (other than the deliberate choice not to get vaccinated).

And that's for sexually transmitted diseases. When a disease can be spread through casual contact—sneezing, coughing, perhaps even breathing—the disease is even harder for people to reliably avoid spreading, or to reliably avoid acquiring. The case for forbidding people from inflicting this disease on others, by requiring them to take reasonably safe and effective steps to keep their bodies from being deadly, is thus even stronger.

So a brief summary: There may well be practical problems with truly mandatory immunization, and it may well be that herd immunity would mean that 90% immunization is good enough to reduce the risk to a level that doesn't merit regulation. There may of course also be practical objections to immunization if the immunization seems unduly risky.

But as a moral matter of individual liberty, it seems to me that there's little support for a claimed freedom from getting immunized—and especially a claimed freedom from getting your underage children immunized. A requirement that people not allow their bodies to be media for unwitting transmission of deadly diseases strikes me as quite compatible with a generally libertarian perspective on the world.

UPDATE: Note that, when I wrote this, the debate was about mandating vaccinations for girls and women, whether because the HPV vaccine was better tested there, was more seen as cost-effective there, or was more likely to benefit the vaccinated themselves (given that a major hazard of HPV is cervical cancer); that's why I focus the analysis on the women in the chain. But to the extent that the vaccination is seen as medically effective for male as well, I think the moral case for compelling it is present for men and boys as well as for women and girls.