Online comments on vaccination 'more influential' than official announcements

The recent measles outbreak in the US has reignited the fierce debate over vaccinations. The Internet has proved to be the main arena for this particular battle, and now a study has examined to what extent online comments influence opinions on vaccination.

Medical News Today recently took an in-depth look atboth sides of the vaccination debate and how it relates to the worrying resurgence of measles in the US.

In that spotlight feature, we explained how pro-vaccination groups blame the rise in measles cases on "anti-vaxxers" - skeptics of the safety of the measles, mumps and rubella (MMR) vaccine, who refuse to vaccinate their children against these conditions. However, the MMR vaccine skeptics believe that the vaccine may increase risk for autism, and claim the right not to vaccinate is part of their human rights.

But where do these two communities get their information from? Is it from health campaigns run by governmental organizations such as the Centers for Disease Control and Prevention (CDC)? Or are people more influenced by the online commentary of their peers?

To investigate, researchers from Washington State University in Pullman conducted two experiments. They publish the results of this study in the Journal of Advertising.

In the first experiment, 129 participants were shown two made-up public service announcements - a pro-vaccination announcement and an anti-vaccination announcement. The participants were told that the pro-vaccination announcement was sponsored by the CDC, while the anti-vaccination announcement was sponsored by the National Vaccine Information Council.

Both of the public service announcements were carefully designed to resemble official publications from the websites of the respective organizations.

As well as the fabricated public service announcements, the researchers also faked comments from a range of fictional online commenters, espousing a variety of pro- and anti-vaccination viewpoints.

The researchers found that the participants were "equally persuaded" by the public service announcements and online comments. "That kind of blew us away," says co-author Ioannis Kareklas. "People were trusting the random online commenters just as much as the [public service announcement] itself."

Expert opinion is more powerful in 'word of mouth' form than official announcements

The participants in the first experiment were not given any information about who the commenters were, and gender biases were avoided by giving the commenters unisex names. However, in the second experiment, participants were given more details about the fictional commenters.

An English literature student, a health care lobbyist and a doctor specializing in infectious diseases and vaccinology were the identities behind the comments, the participants were told. Perhaps predictably, the participants in this experiment attached most credibility to the comments from the fictional doctor.

"We found that when both the sponsor of the [public service announcements] and the relevant expertise of the online commenters were identified, the impact of these comments on participants' attitudes and behavioral intentions was greater than the impact of the [public service announcement] and its associated credibility," the researchers write.

The researchers believe that their findings offer a clue as to why the anti-vaccination movement has been so persistent. The study supports previous research that found people take word-of-mouth communications, whether Internet-mediated or in person, more seriously than they do advertisements.

How should health websites approach reader comments?

This faith in word-of-mouth communication has even led to Science, The Huffington Post and the Chicago Sun Timesbanning anonymous online comments as these publications feel that the comments have the potential to undermine proven science.

However, Kareklas says the team does not subscribe to the practice of taking down comments, as publications would lose credibility if they only posted positive comments.

He suggests instead that health websites should include opposing viewpoints where relevant, but ensure that supporting comments are abundant and can be easily verified, calling for "credible online exchanges where innovative thinking facilitates collaborative problem solving and results in improving customer welfare for all parties involved."

Written by David McNamee

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