Vaccines have been proven time and again to be safe and effective. We know, for example, that the link between childhood vaccinations and autism was fabricated by an unethical scientist.
Yet, there remain many websites that aim to convince parents not to vaccinate their children. A new study examining these anti-vaccine sites found that most use pseudoscience, misinformation, and anecdotal stories to suggest that vaccines are dangerous. Recent outbreaks of measles—which spread, in part, because too few people in the affected areas were vaccinated—highlight how serious these misunderstandings can be.
Researchers from Johns Hopkins University first assembled a list of anti-vaccine websites by using Google, Bing, Yahoo, and Ask Jeeves to search for terms such as “vaccine danger” and “immunizations dangers.” They found 480 online sources that included health websites, personal sites, Facebook pages, and blogs. The researchers analyzed each site to see whether it included misinformation, the sources of such misinformation, and what persuasive tactics each used to convince readers that vaccines are dangerous.
They found that 65.6 percent of the sites claimed that vaccines are dangerous, 62.2 percent claimed vaccines cause autism, and 41.1 percent claimed vaccines caused “brain injury.”
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To support these claims, 64.7 percent used scientific evidence and 30 percent used anecdotes. What was presented as scientific evidence, however, often included misrepresentations of studies and a misunderstanding of epidemiology.
Some of the sites used legitimate, peer-reviewed studies, but misrepresented the conclusion. “So the science itself was strong, but the way it was being interpreted was not very accurate. It was being distorted to support an anti-vaccine agenda,” study author Meghan Moran explained to Live Science.
For example, a number of the sites presented timelines that showed the rate of vaccination increasing at the same time that the number of autism diagnoses were increasing. The sites promoted the implication that these two phenomena were related. As Moran explained, correlation does not equal causation. “Just because two things happen at the same time, that doesn’t mean that one is causing the other,” Moran said.
The anti-vaccine sites often relied on stories from parents of autistic children who believe that vaccines were responsible for their child’s condition. These stories resonate with parents but spread information that is now known to be false. This myth is based on one 1998 study by a researcher who later admitted to falsifying all of the data, as Rewire has reported. Numerous scientists have tried to replicate the findings and all studies have determined that there is no link between vaccines and diagnoses of autism.
The spread of misinformation since the late 1990s and the rise of the anti-vaccination movement has been blamed for a drop in vaccination rates and recent outbreaks of preventable diseases. Earlier this year, a measles outbreak sickened more than 100 people on the West Coast after one person with the virus visited a California amusement park. The Centers for Disease Control and Prevention noted that the majority of people who came down with measles were unvaccinated.
But it’s not just the unvaccinated who are at risk once an outbreak begins. Public health experts explain that in order to truly prevent outbreaks, there needs to be herd immunity by vaccinating at least 90 percent of the population. This protects those who can’t be vaccinated because they are too young or have underlying health conditions.
The researchers believe that the public can learn from reviewing the anti-vaccine websites and understanding the strategies used to dissuade vaccination. Many of the sites mentioned values such as choice (41 percent); freedom (20.5 percent); and individuality (17.4 percent). The sites also promoted using alternative medicine (18.8 percent); eating a healthy diet (18.5 percent); supporting homeopathy (10.2 percent); cleansing the body of toxins (7.1 percent); practicing religion (6.8 percent); breastfeeding (5.5. percent); and eating an organic diet (5.2 percent).
“The biggest global takeaway is that we need to communicate to the vaccine-hesitant parent in a way that resonates with them and is sensitive to their concerns,” Moran explained. “In our review, we saw communication for things we consider healthy, such as breastfeeding, eating organic, the types of behavior public health officials want to encourage. I think we can leverage these good things and reframe our communication in a way that makes sense to those parents resisting vaccines for their children.”