Vaccination campaigns can backfire, warn researchers
Campaigns designed to encourage parents to vaccinate their children against measles, mumps and rubella (MMR) can backfire, according to research.
Academics tested four types of messages designed to promote MMR vaccination with a nationally representative sample of parents in the US.
The trial showed that none of the messages increased parents’ intent to vaccinate, and some of them actually had the opposite effect. The study is in the latest issue of the journal Pediatrics, published online.
“Waiting for a deadly measles outbreak to convince parents to vaccinate is too costly”
In the trial − conducted by Dr Jason Reifler, a social scientist at the University of Exeter, in collaboration with colleagues from Dartmouth College, Georgia State University, and the University of Michigan − parents were randomly assigned to one of five conditions.
These conditions represent four potential strategies available to public health agencies to promote vaccination, as well as a control group for comparison.
One group was given information adapted from (but not attributed to) the US Centres for Disease Control and Prevention (CDC) explaining the lack of evidence that the MMR vaccine causes autism.
Another group was given written information about the dangers of the diseases.
The MMR vaccine
A third group was given images of children who have diseases prevented by the MMR vaccine.
A fourth group was given a dramatic narrative about an infant who almost died of measles from a CDC fact sheet.
And the final group was given a control condition in which respondents read material unrelated to health.
Parents’ beliefs and attitudes about vaccines were surveyed before and after receiving the material, and it was found that none of the messages increased parents’ intent to vaccinate, with some of the messages backfiring.
Dr Reifler, a political scientist at the University of Exeter, said: “Providing parents with information debunking the supposed link between the MMR vaccine and autism did reduce the misperception that vaccines cause autism.
“While this result seems encouraging, there is also significant cause for alarm. The debunking information led some parents − those who are most sceptical about vaccines − to report that they were less likely to vaccinate a future child compared to equally sceptical parents in the control condition.
“Our results show some of the challenges faced in promoting public health. The intervention that was effective in correcting the misperception also reduced intent to vaccinate among some parents.
“Some interventions increased misperceptions. Waiting for a deadly measles outbreak − like in Wales last year − to convince parents to vaccinate is too costly. Knowing how systems like the NHS can effectively promote immunisation is a crucial component of public health.”
The research findings indicated that additional research is needed to determine what messages would be more persuasive.
Any further studies may consider looking at whether more subtle messages that do not induce fear could be explored.
Any approaches should be carefully tested before dissemination to assess their effectiveness, especially among sceptical populations, according to the study authors.
- Read the full study paper in Pediatrics
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