Researchers surveyed a nationally representative sample of 1,000 Americans on their level of concern about vaccine side effects (around a quarter said they were “extremely concerned” or “very concerned”) before dividing them into three groups: one that read a message adapted from the CDC debunking the myth that people can contract the flu from the vaccine, one that read about the danger of the flu, and one that received no additional information. Afterwards, participants answered questions about the safety of the vaccine and whether or not they intended to get it for the coming flu season.

Around 43 percent still said they thought that the flu vaccine could cause the flu, though people who read the myth-busting message were the least likely of the three groups to say so. Among the people who had expressed the most concern about side effects, though, reading the correction tended to push them further in the opposite direction—after learning that the virus in the vaccine couldn’t cause the flu, they were less inclined to get it.

“The corrections we tested were effective at reducing misperceptions—which seems great, until you get to the behavioral outcomes and people say they’re less likely to vaccinate, rather than more,” said study co-author Brendan Nyhan, a professor at Dartmouth College.

The study built on previous research from Nyhan and Exeter University’s Jason Reifler, published earlier this year in the journal Pediatrics, that found a nearly identical effect when parents were exposed to information about the measles-mumps-rubella (MMR) vaccine. After reading that the MMR vaccine wasn’t dangerous to their children, the Pediatrics study found, the most concerned parents were less likely that before to say they would vaccinate their children.

Both political scientists, Nyhan and Reifler have spent the past several years studying what they call the “backfire effect,” or the idea that when presented with information that contradicts their closely-held beliefs, people will become more convinced, not less, that they’re in the right. In one study, when staunch conservatives read information refuting the idea that the U.S. found weapons of mass destruction in Iraq, they tended to believe more firmly than before that it was true; the researchers saw similar effects in studies correcting the notion that President Obama is Muslim and the claim that “death panels” were a part of healthcare reform.

From there, vaccination seemed like a logical next step in their research, Nyhan said: “Vaccines aren’t a partisan or ideological issue, but they’re controversial. They bring up issues of identity and tribalism that feel a lot like politics,” he explained. “I have kids, and talking about vaccines on the playground is like bringing up religion. It’s very weird and delicate and controversial.”