Like a lot of researchers who have taken a hard look at the damage vaccine refusers are causing to public health in the U.S., Dartmouth professor Brendan Nyhan proposes policy adjustments to change their behavior. But I think it will take more than that -- it will take a social movement -- and it's Nyhan's own research that convinced me.
In an article in the New York Times yesterday, Nyhan proposes that parents who want a child to be exempt for non-medical reasons from school vaccination requirements must consult with a health-care provider. However, in Nyhan's own recently published study, parents who expressed negative attitudes about vaccines only hardened their positions after being presented with written messages correcting negative myths about vaccines and promoting their benefits. In theory, such parents might be more open to what their child's pediatrician had to say, but that's not how it seems to work.
Nyhan and his fellow researchers didn't posit why vaccine refusers are so obstinate, but it may have to do with a phenomenon psychologists call reactance. According to this theory, if a person perceives that his freedom of action is threatened, he may rebel against the threatening force. In a 2011 study in Australia, smokers demonstrated reactance, saying they were less likely to quit smoking after being exposed to cigarette-packet warning labels, especially graphic ones.
So how do we get vaccine refusers to change their behavior? When cigarette warning labels didn't curb smoking, government officials turned to tax penalties on cigarettes and limitations on public smoking. Similarly, states that allow parents to exempt their children from school vaccine requirements on non-medical grounds need to tighten the rules.
Nyhan suggests that beyond a parental signature, states should require the sign-off of a health-care-provider and proof that the parents received information about vaccine benefits. By making these changes, Washington state has cut the number of exemptors by 24 percent in two years.
This is a start. Such reforms, however, probably most influence parents who had been too lazy or disorganized to get their kids vaccinated. That will still leave hard-core refusers undeterred. Some may be moved if health-insurance providers begin charging higher premiums to cover unvaccinated individuals, just as they charge more for smokers.
Yet I suspect the most applicable lesson from smoking has to do with what caused its greatest decline: a change in public attitudes. That was a direct result of increased understanding that smokers were harming others with second-hand smoke. Smokers felt the change in popular sentiment not just because they couldn't smoke at their desks anymore but because of the way people looked at them when they lit up. Smoking stopped being cool and came to be seen, properly, as antisocial behavior, a matter not just between the smoker and his doctor, but between the smoker and us all.
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