Whose Risk is Important? Why?

Sitting around in my collection of unopened moving boxes is a copy of In Pursuit: of Happiness and Good Government, in which Charles Murray offers an invaluable insight into how social risk should be calculated. With regard to the link between speed limits and highway deaths, Murray argues that the proper quantity with which we should be concerned is the risk that a driver moving at a proposed speed limit (70 mph, in Murray's example) poses to those driving at the existing speed limit (55 mph, at the time of the book's publication). He wrote that the danger posed by the "fast" driver to himself and to other "fast" drivers is not properly a public concern in a free society. Only the true externality should be accounted, and weighed against the positive goods of the increased limit.

This strikes me as a powerful argument, and one that came immediately to mind when Megan, indicating support for mandatory vaccinations, issued the following obiter dictum.

[P]arents who don't vaccinate their children are able to do so only because most parents do vaccinate theirs.

This is almost certainly true, but it struck me as a poor argument for mandatory vaccinations. I'm not an immunologist, and I don't actually know what the risks actually are, but in the comments, I put forth that only the risk that unvaccinated people pose to vaccinated ones merits consideration. Commenter Rob Lyman enumerated such risks thusly:

Because [1] sometimes the vaccine doesn't "take," because [2] immunity wears off over time, because [3] populations of inccubators encourage mutations which might not have been included in vaccines, and because [4] some number of people can't be vaccinated, the failure of herd immunity cause by elective non-vaccination poses a threat to the non-elective ones.

I replied:

So it appears that between groups 1, 2, and 4, above, there remains a core of effectively un-vaccinated people posing a risk primarily to each other, but also some risk to the vaccinated population by incubating mutations. It is this last risk that should be quantified.

I would then ask: to what extent does the marginal electively unvaccinated person increase that risk. I would then ask how that risk compares to the risk of receiving the vaccine. I don't know what these risks actually are, but it seems reasonable to insist that the first risk outweigh the second before resorting to coercive measures.

Rob subsequently objected to my dismissal of the marginal risk posed by the electively unvaccinated to the non-electively unvaccinated on the grounds that, through either bad health or ignorance, the latter couldn't help their own vulnerability and externalized risk, while the former group could.

My first reaction is to rebel at this distinction. Those in group [4] clearly have not run the risk they would seek to impose on others, and perhaps in group [1] as well. People in group [2] presumably run the risk, but in both case [1] and [2], are there no other alternatives? Cannot anyone concerned about the effectiveness of their own vaccination be tested for the antibodies? My impulse is to look for alternatives before reflexively resorting to coercive vaccinations. But perhaps I am being myopic or hard-hearted.

Unfortunately, I can't end this essay without pulling back the curtain, so to speak, on my own suspicions. No small amount of the energy put into the calls for mandatory vaccinations is simple herd-think: we have accepted the risk of vaccinations for ourselves, and thereby produced some externalized good; you therefore must not be allowed to enjoy that benefit without accepting the same risk. This syllogism is powerfully seductive as a psychological matter, but it's not the same thing as risk management.

And at the risk of descending even further into tinfoil hat territory, I have difficulty in trusting the motivations of Megan's more zealous commenters. I suspect that the enthusiasm of many self-identified "progressives" for mandatory vaccinations is a function of their perception, not entirely unjustified, that resistance to vaccination programs is overrepresented among highly religious people, and that coercive measures is yet another front in their ongoing efforts at "conservative ethnic cleansing" about which I have written much.

UPDATE: After taking me to task for my tinfoil hattery, Trumwill brings up another class of unvaccinated persons that I had not considered: children too young to receive the vaccine but who are nonetheless vulnerable to the disease. I want to state that absolutely the risk to such children should be accounted when contemplating mandatory vaccination programs on the grounds that such risk is univeral -- although I would still insist that such programs result in positive-sum utility.