There’s more than one way to persuade people to vaccinate

doctor talking to a father

Some research suggests that the language doctors use affects parents’ willingness to vaccinate their children. But exposure to antivaccine views and other psychological tricks combine to keep some parents undecided. 


Measles used to sound like such an old-fashioned disease. But the current Disneyland measles outbreak has put it back in the news, with 141 cases reported so far this year in 17 states and the District of Columbia. While the outbreak has some parents who formerly delayed or refused to vaccinate racing to the clinic, others are becoming more entrenched in their belief that vaccination is both dangerous and futile.

Research has begun to examine why people fear vaccines, and what can be done about it. Some studies show that fear is a powerful motivator for convincing people to vaccinate. But other work finds that fearful facts have the opposite effect. Some studies suggest that perhaps doctors should approach vaccines as a given, or maybe an equal conversation would be better. But in all of the research, one thing is clear: There is not a single, foolproof way to convey that the benefits of vaccination far outweigh the harms.

“At the end of the day, parents who vaccinate and parents who don’t vaccinate are motivated by the same thing — doing right by their kids,” explains Kristin Hendrix, a pediatric health services researcher at Indiana University School of Medicine in Indianapolis.

Why so scared?

Parents never lack for things to worry about.  But in theory, vaccination shouldn’t be one of those things. The data are clear: Vaccination works. It rid the world of smallpox, has drastically reduced the incidence of polio and until recently, made measles a thing of the past in the United States. And even though some diseases are now so rare as to seem medieval, vaccination remains hugely important in keeping disease at bay.

But fear and worry about the dangers of vaccines has made skeptics of some parents. Some of the concern may be due to exposure to anti-vaccine theories, such as the now discredited connection between the measles/mumps/rubella vaccine and autism.  “A lot of information that is passed around to people from the media tends to promote the idea that information [about vaccines] is being hidden from them or they don’t necessarily know the truth,” says Karen Douglas, a social psychologist at the University of Kent in England. “That can appeal to people who might be mistrustful or might want to have complete, 100-percent-solid evidence that something isn’t harmful before they do it.”

Fear is a powerful motivator. In psychology, a fear appeal attempts to scare someone into altering their behavior. The best fear appeals present both a big threat, and an effective way of getting rid of the threat.  Just as fear may be preventing people from vaccinating their kids, it may also offer a strategy for promoting immunization. The threat is getting sick. To get rid of the threat, get vaccinated. Since the majority of the population still does get their shots on time, these fear appeals, combined with the ease of getting the shots, do appear to work.

But for some, vaccines have become victims of their own fear appeal success. “The more effective vaccines are, the fewer cases of disease will emerge and the less the public will perceive the diseases as dangerous,” explains Elizabeth Wolf, a pediatrician who studies vaccine delivery at the University of Washington in Seattle. Many parents will have never seen a child with the measles, let alone someone with, say, diphtheria or rubella.

And through social media, fear appeals about the vaccines themselves get more psychological weight. In the past, someone who mistrusted the public health system or didn’t trust vaccines may or may not be able to find others in their area who shared those beliefs, explains Kumanan Wilson, who studies vaccination and public health at the Ottawa Hospital Research Institute in Canada. “But what used to happen geographically can happen virtually,” he says. “People are finding each other on the Internet and reinforcing each other’s beliefs. A mother questioning vaccines finds other mothers who say, ‘yes, you are right,’ and they start to mistrust the original sources of health information.” Instead of fearing the disease, the parents may start to fear the vaccine — and mistrust the providers who would vaccinate their children.

It’s all about the baby

The risk of catching measles, mumps or rubella may still be very low, and the risk of a vaccine’s side effects even lower. But presumably, people would still want to vaccinate to perpetuate herd immunity — the protection for vulnerable individuals that comes from most of the population being immune to the disease.  We should all still get vaccinated for the sake of those who can’t be, the thinking goes.

Unfortunately, when it comes to vaccination, these altruistic appeals have little weight. “We gave parents information about the societal benefits of vaccination, and we found that it didn’t have too much of an impact on people immunizing,” Hendrix says. “The information doesn’t hurt and it’s important, but in and of itself it may not be enough to motivate families.”

What did increase parents’ intention to vaccinate was emphasizing the benefit to the child. Parents care about their own children, not other people. “We’ve found most parents weren’t concerned with herd immunity, they were concerned with the child in front of them,” says pediatrician Margaret Danchin of the Royal Children’s Hospital in Melbourne, Australia. The benefits to the child might end up far more persuasive than any altruistic arguments.

Not just the facts, ma’am

But just a list of risks and benefits may not be enough on its own.  “Providing the facts is part of the consultation, but it’s got to be engaging,” Danchin says. “You’ve got to develop a platform of trust and then start providing facts.”

It’s also important to realize that this approach may only work with parents who are hesitant about vaccines or who have questions. For those least inclined to vaccinate, presenting information to correct myths might trigger disconfirmation bias, suggests Brendan Nyhan, a political scientist at Dartmouth College.When presented with information that contradicts our beliefs, we may become biased against the new — and unwelcome — revelations. “When it comes to issues people have strong feelings about, we’re not the dispassionate arbiters of truth we’d like to think we are,” he says. “When we hear unwelcome information we have a tendency to resist it and to think of reasons why it’s wrong.”

Trust between health care providers and parents is going to be the most important part to a positive reception of a discussion on the benefits of vaccination.  “A physician needs to realize early on when there’s no point in having the discussion,” says Wilson. “By showing continued care and concern for the child’s well-being the parent may come to trust the doctor in the long run.”

Presumption or persuasion

While shame and fear may have limited success in promoting vaccination, there are other kinds of social persuasion. A December 2013 study in Pediatrics by Douglas Opel at the University of Washington showed that the attitude of the doctor might also play a role. If a doctor simply presumes that the parent will be getting the child vaccinated, they may encounter less resistance than if they enter into a more participatory dialog where the parent can air their concerns.  

But Danchin says she doesn’t really believe that the presumptive approach will be more effective. In a written response to Opel’s 2013 study, Danchin, her colleague Julie Leask, and others at the University of Sydney note that while parents in the study said they agreed to vaccinate, they didn’t actually have to go through with it. Danchin and colleagues worry that a doctor’s presumptive attitude might increase a parent’s doubts and decrease their trust. Instead, they promote an approach that offers plenty of facts about both the risk of disease and the risks associated with the vaccine.

In the end, the most persuasive argument for vaccination will vary from parent to parent. Some may require gentle persuasion, while others may be content with a list of the facts. And of course, a few may be completely unwilling, regardless of the argument. “It’s hard to tailor the information,” Hendrix notes. “That’s the major drawback to trying to target people’s specific fears from a public communication perspective.”

There may not be one psychological method available to persuade everyone to vaccinate. But, as with seatbelts, smoking and other behaviors, legislation could make vaccination mandatory for those without the need for a medical exemption. School requirements for up-to-date vaccination records, state laws requiring vaccination for employment, and rigorous opt-out policies might succeed where persuasion fails. “Click it or ticket” worked for seatbelts. Perhaps the day has come for “Don’t face a fine, get your shots on time.”

Luckily, parents who adamantly refuse to vaccinate are in the minority. Unluckily, as the Disneyland outbreak shows, that tiny minority is still needed to keep infectious diseases from rising again. “The reality is that most people do get vaccinated, “Wilson says. “Maybe it’s 90 percent, but you need 95 or 100 percent. It’s challenging to get 100 percent of the population to agree to something. It’s not that there’s a disastrous failure of messaging. It’s that the threshold for success is so high.” 

Bethany was previously the staff writer at Science News for Students. She has a Ph.D. in physiology and pharmacology from Wake Forest University School of Medicine.

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