ABSTRACT & COMMENTARY
CDC Messaging on MMR Vaccine Safety Paradoxically raises Parental Fears
By Hal B. Jenson, MD, FAAP
Dean, Western Michigan University School of Medicine, Kalamazoo, MI
Dr. Jenson reports no financial relationships in this field of study
SYNOPSIS: A national survey of parents found that information from the CDC about vaccines and adverse facts may not be effective in correcting parental misperceptions. Some attempts to heighten parental awareness about vaccine-preventable diseases and vaccine safety may actually be counterproductive.
SOURCE: Nyhan B, et al. Effective messages in vaccine promotion: A randomized trial. Pediatrics 2014;133:1-8.
A nationally representative 2-wave web-based survey was conducted in the United States in June-July 2011 among 1759 parents age 18 years and older having children age 17 years or younger. The first survey wave measured pre-intervention measures of health and vaccine attitudes. Parents were then randomly assigned to a control group receiving no information or to one of the four intervention groups that received information taken nearly verbatim from vaccine messages created by the Centers for Disease Control and Prevention:
- information explaining the lack of evidence that MMR vaccine causes autism;
- narrative information about the dangers of diseases prevented by MMR vaccine;
- images of children with diseases prevented by MMR vaccine;
- a dramatic narrative about an infant who almost died of measles.
The second survey wave measured perceptions about MMR vaccine, including adverse effects and intent to give MMR vaccine to their future children. None of the interventions increased parental intent to vaccinate their future children.
Among parents who were deemed from the first wave survey as having the least favorable attitude toward vaccination, the intervention providing information that refuted the link of MMR vaccine with autism successfully reduced this misperception about the vaccine (from 8.9% to 5.1%), However, it also decreased parental intent to vaccinate their children. Providing disease images increased the belief of a link between MMR vaccine and autism, and providing narrative information about the dangers of diseases prevented by MMR vaccine increased belief in vaccine serious adverse effects.
It is discouraging that no intervention using pro-vaccine messages created by the CDC increased parental intent to vaccinate their future children with MMR vaccine.
Informational messages aimed to inform parents and correct misperceptions about vaccine safety and adverse effects may not always be effective, and may often be counterproductive. It appears that there is a danger-priming effect in which providing dramatic narrative information or images of sick children also increases misperceptions about the MMR vaccine. These results are consistent with other evidence that show that attempts by providers to scare parents with emotive information and stories may paradoxically increase concerns among parents who are hesitant to immunize their children.
The findings of this study confirm that there are significant challenges informing parents about topics that have been highly politicized, and that the lingering adverse effects of misinformation is strongly persistent and highly significant. In the instance of MMR vaccine, much of this parental misperception results from poorly worded or fraudulent reports in the scientific literature, such as the now-discredited publication in 1998 that putatively linked MMR vaccine with autism.
Parental resistance to persuasion even using factually correct information underscores the significant obstacle that health care providers face in educating parents about vaccines, especially with very limited time during office visits.