Effective Messages in Vaccine Promotion: A Randomized Trial

Researchers conducted a randomised trial to test 4 different ways of educating parents on the need and benefits of vaccinations - specifically, to test the effectiveness of messages designed to reduce vaccine misperceptions and increase vaccination rates for measles-mumps-rubella (MMR) in the United States (US). An internet-based, nationally representative 2-wave survey experiment was carried out (June-July 2011) with 1,759 parents age 18 years and older residing in the US who have children in their household age 17 years or younger. Parents were randomly assigned to receive 1 of 4 interventions: (i) information explaining the lack of evidence that MMR causes autism from the Centers for Disease Control and Prevention (CDC); (ii) textual information about the dangers of the diseases prevented by MMR from the Vaccine Information Statement; (iii) images of children who have diseases prevented by the MMR vaccine; and (iv) a "dramatic narrative" about an infant who almost died of measles, from a CDC fact sheet. Other participants were assigned to a control group.

It was found that none of the interventions successfully increased the parents' intention of vaccinating their children. "Refuting claims of an MMR/autism link successfully reduced misperceptions that vaccines cause autism but nonetheless decreased intent to vaccinate among parents who had the least favorable vaccine attitudes. In addition, images of sick children increased expressed belief in a vaccine/autism link and a dramatic narrative about an infant in danger increased self-reported belief in serious vaccine side effects."

In conclusion, the study finds that current public health communications about vaccines may, for some parents, actually increase misperceptions or reduce vaccination intention. "Attempts to increase concerns about communicable diseases or correct false claims about vaccines may be especially likely to be counterproductive. More study of pro-vaccine messaging is needed."