Study: Teaching anti-vaxxers that the flu shot is safe only makes things worse

Convincing people to get vaccinated is going to take a lot more than good information, researchers show

Published December 8, 2014 4:19PM (EST)

           (Reuters/Brian Snyder)
(Reuters/Brian Snyder)

We're in for a nasty flu season, the CDC warned last week, thanks to the fact that this year's flu vaccine doesn't seem to be working as effectively as usual. It has zero chance of working, of course, if you don't get vaccinated to begin with, as public health officials are perpetually trying to get more people to do. Some people may just not have bothered to get the shot, but others may be intentionally avoiding it out of fears that it might be dangerous -- and a new study from researchers at Dartmouth and the University of Exeter highlights just how difficult it is to change their minds.

The flu vaccine itself doesn't cause the flu, but 43 percent of Americans believe it does, found researchers Brendan Nyhan and Jason Riefler. Their study, published in the journal Vaccine, attempted to figure out if correcting that misperception would inspire more people to get vaccinated. Long story short: it didn't. When their subjects, a representative sample of U.S. adults who responded to a 2012 survey, were given information taken from the CDC explaining that neither the flu shot nor nasal spray can transmit the flu, they actually became less likely to say they'd get vaccinated. The message backfired.

This is obviously concerning, although it's not very surprising. In a study last March, Nyhan and Reifler uncovered a similar phenomenon surrounding the MMR vaccine, which is plagued by a tiny but vocal contingent of parents swayed by the false belief that it causes autism. They determined that presenting people with the facts -- as opposed to, for example, frightening them with stories about children contracting the measles -- was, appropriately enough, the best way of educating them. But they also found that, for anti-vaxxers, no message was effective: and there, as here, the facts backfired. Those parents, already highly distrustful of the vaccine, became even less likely to vaccinate their children.

Dealing with flu vaccine misinformation has soon advantages over the MMR shot, Nyhan told Salon: for one, even though the idea that it causes the flu is pervasive, it's not nearly as pernicious. The myth wasn't begun by a retracted and debunked study that just won't go away, helped along by celebrities like Jenny McCarthy. Vaccines are often made from a weakened or killed strain of virus they're intended to prevent against, and so it's understandable why a layperson might come to believe it could make them sick. Setting the record straight, Nyhan and Reifler showed, is simple enough: in their study, people presented with information explaining that the flu vaccine was safe became less likely to believe it was unsafe.

But it didn't make them more likely to get vaccinated. And a high rate of unvaccinated people, regardless of how educated they are, continues to pose a public health threat. None of the messages tested in the study, including one that emphasized the health risks of the flu, were able to positively influence people's intention to get vaccinated.

"We shouldn't think of messaging as a silver bullet," Nyhan said. It's good to try, he added, but if public health officials are going to get better at promoting vaccination, they're going to need to rethink the ways they reach people. One approach that might work? Reaching out to people through their schools and workplaces, Nyhan suggests, might be a good place to start. "I think messages from distant public health agencies are likely to be less effective than trusted community institutions and organizations," he said.

By Lindsay Abrams

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Anti-vaxxers Cdc Flu Vaccine Public Health