Bioethics Forum Essay
Measles, Vaccination, and the Tragedy of the Commons
After having been virtually eliminated in the United States in the year 2000, measles have made a comeback, with nearly 150 cases in 17 states and nearly 30 confirmed cases of the illness in the Canadian provinces of Ontario, Quebec, and Manitoba.
Blame for the current measles outbreak has largely fallen on the “anti-vaxxers” and, more specifically, on parents who choose not to vaccinate their children against measles. In the U.S. and Canada, exemptions from mandated vaccines permit parents to opt out of vaccinating their children for medical, religious, or philosophical reasons.
In the U.S., all states mandate certain vaccines for children attending schools, but most states allow exemptions for religious reasons, and 20 states allow exemptions for philosophical reasons. California recently introduced a bill that would prohibit all nonmedical exemptions. If it passes, California will join two other states with the same prohibition. North of the border, Ontario, New Brunswick, and Manitoba are the only Canadian provinces that mandate vaccinations for school children, and all allow exemptions for medical, religious, and philosophical reasons.
The Holy Grail in the vaccine world is to achieve “herd immunity,” the point at which the majority of a population is immune to a particular illness. Experts say that 90 percent to 95 percent of the population needs to be vaccinated in order to achieve herd immunity. Herd immunity also helps protect vulnerable members of the population who cannot be vaccinated, such as infants and young children, and individuals with certain illnesses.
Once parents come to realize that vaccinating their children is the best defense against certain illnesses – and indeed in their child’s best interest – one would hope that parents would opt to vaccinate. But there are reasons why they might not.
To understand why, think of vaccination and the quest for herd immunity as a collective action problem. Garrett Hardin’s “tragedy of the commons” illustrates the basic logic of collective action problems. Imagine that 50 farmers share common land (“the commons”) upon which they graze their sheep. The commons are lush, and so each farmer can easily allow four sheep to graze at a given time without depleting the resource. But imagine that each farmer seeks to maximize his own good (what economic theory refers to as “rational” behavior) and it is better for him to graze more sheep than fewer. The farmers will, in effect, be “free-riding” – in this case, taking more than their fair share of the common resource while benefitting from the restraint of others. The trouble is that, while adding one more sheep to the commons does not deplete the resource, adding 50 does. The combined actions of each farmer, acting rationally, leads to an outcome that is worse for all.
The tragedy of the commons reveals that what is good for the individual is at odds with what is good for all. This is the basic logic of collective action problems. We see a similar logic in the case of vaccines. If most get vaccinated, then everyone will be better off. But it would be best for any particular individual if all others got vaccinated and he or she did not. That way, the individual could enjoy the benefits of the common good (herd immunity) without bearing any of the costs (e.g., risk of possible side effects or complications associated with vaccine). This, again, is a free-rider temptation. The trouble is that if everyone thought that way, no one would become vaccinated and everyone would be at risk of falling ill.
From this perspective, anti-vaxxers are not ill-informed parents with distorted views of what is in their child’s best interest. They are acting perfectly rationally. The trouble is that there are enough of them to generate the tragedy of the commons. Hence, vaccination levels drop and measles rates rise.
Thus, even if efforts to educate the public about the risks and benefits of vaccines succeed, wherever there is herd immunity there is a temptation to free-ride. Policies are often enacted to counteract this temptation. These can take many forms. One would be to appeal to the common good in order to motivate action. Since voluntary compliance is best, policies that encourage (or, to borrow from Cass Sunstein, “nudge”) a concern for the common good (e.g., “Help keep your city clean.” “Prevent the spread of measles.”) are preferable.
But if nudging fails or, as in the case of vaccination, the stakes are very high, then heavier-handed interventions may be needed. There are fines for littering in many municipalities because appealing to clean common spaces does not always work. Similarly with vaccines, since voluntary compliance cannot be guaranteed, sterner measures may be needed to secure near-universal vaccination. Time will tell if California’s measures are indeed the answer, but the proposed legislation to toughen up on vaccine exemptions is an important first step.
Katharine Browne is a postdoctoral fellow at Novel Tech Ethics at Dalhousie University in Halifax, Canada.
Posted by Susan Gilbert at 02/25/2015 10:33:30 AM |