Amanda Marcotte in Slate:
While some false beliefs, such as astrology, are fairly harmless, parents who believe falsely that vaccination is dangerous or unnecessary for children present a real public health hazard. That's why researchers, publishing in Pediatrics, decided to test four different pro-vaccination messages on a group of parents with children under 18 and with a variety of attitudes about vaccination to see which one was most persuasive in persuading them to vaccinate. As Chris Mooney reports for Mother Jones, the results are utterly demoralizing: Nothing made anti-vaccination parents more amendable to vaccinating their kids. At best, the messages didn't move the needle one way or another, but it seems the harder you try to persuade a vaccination denialist to see the light, the more stubborn they get about not vaccinating their kids.
Brendan Nyhan of Dartmouth College and his colleagues tested four different messages on parents. Mooney describes them:
The first message, dubbed “Autism correction,” was a factual, science-heavy correction of false claims that the MMR vaccine causes autism, assuring parents that the vaccine is “safe and effective” and citing multiple studies that disprove claims of an autism link. The second message, dubbed “Disease risks,” simply listed the many risks of contracting the measles, the mumps, or rubella, describing the nasty complications that can come with these diseases. The third message, dubbed “Disease narrative,” told a “true story” about a 10-month-old whose temperature shot up to a terrifying 106 degrees after he contracted measles from another child in a pediatrician's waiting room.
The fourth message was to show parents pictures of children afflicted with the diseases they could get without vaccination. Both the pictures and the horrible story about measles increased parental fears about vaccinations.