Vaccine Education Efforts Backfire, New Study Says
Parents who believe that the measles-mumps-rubella (MMR) vaccine causes autism do not change their minds even after receiving information from public health researchers refuting the link, according to a new study. For parents with the least favorable attitudes toward vaccines, receiving pro-vaccine information caused a further decrease in intention to vaccinate their children.
The peer-reviewed study, “Effective Messages in Vaccine Promotion: A Randomized Trial,” published in the journal Pediatrics, surveyed 1,759 parents age 18 years and older who have children in their household age 17 years or younger. Parents were randomly assigned to receive one of four interventions: (1) information explaining the lack of evidence that the MMR vaccine causes autism from the Centers for Disease Control and Prevention; (2) Vaccine Information Statements from the CDC that explain both the benefits and risks of a vaccine to vaccine recipients; (3) images of children who have diseases prevented by the MMR vaccine; and (4) a dramatic narrative about an infant who almost died of measles from a Centers for Disease Control and Prevention fact sheet.
None of the interventions increased parental intent to vaccinate their children. Parents with the least favorable attitudes towards MMR vaccines showed decreased intent to vaccinate their children after receiving information refuting a causal link to autism. Additionally, parents shown images of sick children increased their belief that vaccines cause autism. The dramatic narrative about an infant in danger increased belief in serious vaccine side effects.
“The first message of our study is that the messaging we use to promote childhood vaccines may not be effective, and in some cases may be counterproductive,” said Brendan Nyhan, Assistant Professor of Government at Dartmouth College, who researches misconceptions about health care. “We need more evidence-based messaging about vaccines. We don’t know what works, and we need to learn more, rather than relying on hunches or intuition… We suggest that people are motivated to defend their more skeptical or less favorable attitudes towards vaccines… We shouldn’t put too much weight on the idea that there’s some magic message out there that will change people’s minds.”
According to Donald W. Miller Jr., MD, Professor of Surgery at the University of Washington, “fifty years ago, when the immunization schedule contained only four vaccines [for diphtheria, tetanus, pertussis, and smallpox], autism was virtually unknown… Today, one in every 68 American families has an autistic child… Four million American children have Attention Deficit Hyperactivity Disorder. One in six American children are now classified as ‘Learning Disabled.’ …New knowledge in neuroimmunology [the study of how the brain’s immune system works] raises serious questions about the wisdom of injecting vaccines in children…”
The study concludes by suggesting ways to improve messaging outcomes, including communicating more subtlety to avoid backlash and make parents feel better about themselves, reducing or eliminating fear-based narratives, and using pediatricians as messengers due to their perceived trustworthiness by parents.
Centers for Disease Control and Prevention, “Vaccine Information Statements (VIS),” cdc.gov, Jan. 24, 2014
Joseph Brownstein, “Antivaccination Parents Dig in Heels Even after Receiving Medical Info,” scientificamerican.com, Mar. 3, 2014
Chris Mooney, “Study: You Can’t Change an Anti-Vaxxer’s Mind,” motherjones.com, Mar. 3, 2014
Brendan Nyhan, et. al., “Effective Messages in Vaccine Promotion: A Randomized Trial,” pediatrics.aappublications.org, Mar. 3, 2014
Shankar Vedantam, “When It Comes to Vaccines, Science Can Run Into a Brick Wall,” npr.org, Mar. 4, 2014