World Health Matters (United States): Can ‘vaccine sceptics’ be won over?

by Gary Finnegan: The question of whether vaccines cause autism may have been settled long ago but the debate on how to share this message with the public is far from finished.

A series of recent publication have found that bombarding vaccine sceptics with scientific facts is worse than futile – it many even backfire. By reminding them of the thoroughly debunked claim made in a paper published (but since retracted by The Lancet), parents become more hesitant about vaccination.

In fact, even where parents state that they do not believe there is an association between vaccines and developmental disorders, the likelihood of their children being vaccinated still falls once they are reminded of the controversy.

But a new study published in the Proceedings of the National Academy of Sciences, suggests it may be possible to overcome anti-vaccine views. The key, they believe, is to remind sceptics, with words and images, why vaccines exist.

Psychologists at the University of Illinois and the University of California at Los Angeles (UCLA) tested 315 participants’ views about a number of potentially controversial subjects, including their attitude towards vaccines and their willingness to vaccinate their children.

Participants were then randomly assigned to one of three groups. The first looked at materials challenging the anti-vaccination point of view. The second, a “disease risk group,” focused on the risks associated with measles, mumps and rubella.

Participants read a paragraph written by a mother about her child’s infection with measles; saw pictures of a child with measles, a child with mumps and an infant with rubella; and read three short warnings about the importance of vaccinating one’s children. This intervention was more in-depth than those in the previous, unsuccessful study, according to the authors.

A third group, a control group, read about a subject not associated with vaccines.

Afterwards, participants again completed the vaccine attitude evaluation and answered questions about their past vaccine behaviours and their intention to vaccinate their children in the future.

“We found that directing people’s attention to the risks posed by not getting vaccinated, like getting measles, mumps and rubella and the complications associated with those diseases, changed people’s attitudes positively towards vaccination – and that was for even the most sceptical participants in the study,” said researcher Zachary Horne. “Actually, the largest effect sizes were for people who were the most sceptical.”

“Of course, the sceptics are the people with the greatest amount of room to move, so in a sense that finding is unsurprising,” Hummel said. “But it’s also extremely important, because those are precisely the people you want to move. That’s the kind of result we were really looking for.”

Horne said he thinks the study was successful in part because it addressed parents’ primary concern – their children’s well-being.

“People who fear vaccines ultimately do care about the safety of their children, so our manipulation focuses on the safety of their children,” he said. “So there’s not just one calculation in your decision whether to get a vaccination, but now there are two.”