The Herd That Has the Immunity

Paul Jacob
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Posted: Feb 08, 2015 12:01 AM
The Herd That Has the Immunity

Hillary Clinton and Barack Obama gave cautious support for the anti-vaxxer cause a few years ago. While running for the presidency in 2008, Obama called the alleged link between autism and vaccination scientifically “inconclusive.” In the same year, Mrs. Clinton went further, expressing her support for an official study to track down “possible environmental causes” of autism “like vaccines.”

No scandal — though the eventual winner of the race did win a few “Pinnochios” for his statement. (Studies at that time had already determined no such link, hence the Washington Post’s awarding of demerits to both Obama and his Republican opponent, John McCain, for their suggestions otherwise.)

But only now that Hillary and Barack have stood up for vaccination, and Republican politicians Chris Christie and Rand Paul have openly talked about the risks of (as well as of parental rights and responsibility regarding) childhood vaccination has the issue hit the headlines. Indeed, the hot issue last week became mandatory vaccination.

As in state and federally mandated vaccination of children . . for the usual suspect list of diseases I got vaccinated for as a child, and which my children, in turn, received the prescribed dosages (though, on my wife’s delayed schedule, not according to state demands or the doctor’s usual schedule).

Of course, discussion of such talk in politics and in major media tends to the hysterical and simple-minded. Just as folks tend to move from “is” statements quickly and jerkily to “ought” statements (as David Hume famously observed), talking heads on TV quickly shift from chatting up the obvious benefits of past vaccination programs (and they are legion: millions of lives saved, after all) to the absolute necessity of requiring vaccination, backed by government force.

Science writer Ronald Bailey offered a more modest proposal. “Vaccination is arguably the greatest public health triumph of the past century,” he begins. But he continued not by calling for mandating vaccines, but for social pressure: “person-to-person shaming and shunning.”

Of the “anti-vaxxer” parents. That is, of the folks who refuse to let their children be vaccinated.

Shaming is one way to solve such problems — it is a traditional, manners-level version of “social control,” as social scientists like to say. And it is a much less extreme solution to such problems.

But what is the problem, at base?

Those who fear a negative personal effect from vaccination and refuse to vaccinate themselves or their children become “free riders,” as economists put it. They gain a de facto immunity without having to pay — either in money or in the small risk that vaccinations do indeed demonstrate.

This particular free rider benefit depends on the concept of “herd immunity.” That’s a conjectured level of protection for individuals who lack biological immunity. This immunity accrues to them by the overwhelming presence of vaccinated (or otherwise immune) people in a population. The disease can’t spread because it hits too many dead ends in healthy hosts. The modal target resists the infection, and so it doesn’t spread to the members of population who aren’t similarly immune.

That’s as I understand it anyway. As I often caution: I am not a doctor, I don’t even play one on TV.

But there’s a wrinkle to this herd immunity (do you like thinking of yourself as a head of cattle, by the way?): the more anti-vaxxers there are, the less the herd immunity. Epidemiologists estimate that herd immunity kicks in only at the higher concentrations of immunity in a population: probably above 90 percent.

And recent outbreaks of measles at California’s Disneyland and elsewhere suggest that Americans are losing the herd immunity that had seemingly eradicated that disease, and others, such as mumps and whooping cough, decades ago. The anti-vaxxers are endangering the population. And the biggest losers are those people whose immune systems are so endangered that vaccination does them no good: cancer patients and the like.

I don’t know if Bailey’s shaming strategy can work — though I suspect it can, since such strategies seem to move people to vote for bad presidents over and over. Unfortunately, different political groups are susceptible to different types of shaming. So it could get tricky.

As has been often noted the last few days, though the anti-vaxxer trend has mainly tended to “infect” (as a “meme”) urban populations of left-leaning folks — epitomized by Hollywooders Jenny McCarthy and Jim Carrey — the new backlash against anti-vaxxer rights has come strongest from the left-leaning media.

Republican “offenders” provide cover?

Apparently, those of the Democratic herd think they have immunity . . to criticism.