We know that vaccines aren't a partisan issue. There are pro- and anti-vaxxers on both sides of the political spectrum. Even the science-minded President has, at times, equivocated on the issue. But as the vaccine debate took on a political pitch this week — with Republicans firing back at Obama's suggestion that parents "get your kids vaccinated" — how and why people believe what they do about immunizations was on the minds of many.

I called Brendan Nyhan, a political scientist at Dartmouth who specializes in the sometimes magical thinking people have in politics and health care. In a study on perceptions of flu shots, he found correcting myths had the opposite of the desired effect on the most vaccine-skeptical among us. In another study on the measles, mumps, rubella vaccine, he found that myth-busting actually increased some parents' wariness about the shot. In his political research, he has demonstrated that giving people corrective information can deepen their misperceptions — findings that dishearten any debunker.



Here's our interview about why it's so hard to get people to change their minds about vaccines, why corrective information fails, and how to prevent vaccine denialism in the first place. What follows has been lightly edited for clarity.

Julia Belluz: If I had to briefly sum up your research findings, I'd say: it's near impossible to change peoples' minds. Are vaccine beliefs any different from other types of beliefs?

Brendan Nyhan: Vaccine beliefs are a lot like the political beliefs my co-author [Jason Reifler] and I study. People feel passionately, they are not inclined to hear contradictory messages, and there are all sorts of myths circulating. The way people reason about vaccines, it's the same as the way people reason about other controversial topics.

Vaccines are a victim of their own success here. JB: And yet the evidence on the benefits of vaccines is overwhelming. Why is it so hard to get some parents on side?

BN: The benefit is not tangible in any way. It's not a case where your child is sick, you get a medicine, they get better, and you can see it. With vaccines, your child is well, you give them a vaccine, they stay well. The only potential downside is the perspective of certain parents who focus on these myths about side effects. That’s really tough.



That’s part of the reason vaccines historically have been so controversial. It goes back to the very first vaccines, not just the MMR-autism scare in 1998. People have always been suspicious of vaccines. There has always been an instinctive response to the idea of using a disease to protect yourself against the disease. It gives people the heebie jeebies. Finally, many of the diseases that vaccines prevent today are essentially invisible in the US. Vaccines are a victim of their own success here.

JB: Who most influences parents' thinking about vaccination?

BN: Parents rate their child’s doctor as their most-trusted source on vaccines by far. For all the coverage of Jenny McCarthy, parents tell us their pediatrician is who they trust and listen to. That’s why providers are so important. For similar reasons, we should promote vaccines from the bottom up within communities that are at risk of not getting vaccinated.

For all the coverage of Jenny McCarthy, parents tell us they listen to their pediatrician.

During the Ebola outbreak in West Africa, there was a moment when the medical teams were trying to fight the epidemic by communicating the science of how to prevent the spread of the diseases. But they weren’t trusted. When they started working with community leaders and using those leaders in turn to work with people within communities, that’s when they started changing peoples' practices.

In the US, most places have very good levels of vaccination. The US doesn't have a vaccine crisis. We have pockets of un- and under-vaccinated people that create potential hotspots. It's important to be targeted in our approach. In all those places where people are vaccinating, we don't want to scare them.

JB: You've written about the "backfire effects" of being too hard in trying to convince people to see another point of view. How does that relate to vaccines and how should we address the vaccine-hesitant?

BN: My co-authors and I have found that corrective information about controversial issues like vaccines is often ineffective and can even have counterproductive effects. In this case, we found that debunking myths about the MMR vaccine and the flu shot can make people who have the least positive views of vaccines less likely to intend to vaccinate rather than more.

A better approach is to help healthcare providers communicate more effectively. There are too many providers who are too accommodating in their language about alternative schedules or selective vaccination. When my son was born, we went to a pediatric practice in Chapel Hill, North Carolina, and the first thing they said to us was: 'We're willing to work with you on vaccines.' I interpreted that as meaning, 'We’re open to negotiating vaccines with you.' We said, 'No, no, we want everything.' But the danger is that if that’s your opening offer as a doctor, parents may take it.

JB: How does the language doctors use impact whether people vaccinate their kids or not?

BN: Studies have found that providers who use presumptive language, saying, 'It’s time for some shots,' are much more likely to have successful vaccine compliance than providers who use participatory language like, 'What do you think about shots?' It's of course important to respect patient autonomy but I think, at the same time, the language providers use gives patients a cue about the strength of the medical evidence.

If you roll into the emergency room on a stretcher with a gun shot wound, no one says, 'How do you feel about getting bullets out of you?' They say, 'We need to get this out of you now.' There is a move in medicine toward participatory approaches in contexts in which the benefits are less clear. But this is an area where the science is very clear and the language we use should reflect that.



We need to create conditions where we don't have to change as many minds about vaccines in first place.

JB: There's a movement that seems to be bubbling up in the US: the "vaccine delayers." These parents who don't quite refuse vaccines, but they opt for alternative vaccine schedules, delaying some shots and skipping others. What do you make of it?

BN: It’s a tough issue because a certain group of parents are used to being in charge of their kids' healthcare and customizing their own personal healthcare in a way that seems consistent with alternative vaccine schedules. People have an idea that they know what their child needs and what their child is ready for. But federal schedules are based on the best-available science. Making up your own is just delaying protecting your kid. The danger is they increase the amount of time kids are at risk for these diseases.

JB: Knowing that it's hard to change peoples' minds, how do you deal with vaccine denialism?

BN: The best approach is to create conditions where you don't have to change as many minds in first place. We should protect the social consensus around vaccination and prevent it from being politicized, from turning into a partisan debate between Chris Christie and Rand Paul on one hand and Obama on the other. That would be the fastest way to squander the gains we have made and create conditions where some of these diseases could return.