Chris Mooney in Mother Jones (Tom E. Puskar/AP):
Vaccines: Here, the undeniable reality is that childhood vaccines are safe and do not cause autism. So do liberals deny this fact more frequently than conservatives?
Recent research suggests the answer to that question is “no.” In a 2013 paper published in PLOS One, for instance, Stephan Lewandowsky and his colleagues surveyed a representative sample of 1001 Americans about their ideological beliefs and their views on contentious science topics. That included vaccines, where they used a five-item questionnaire to assess people's views, including statements like “I believe that vaccines are a safe and reliable way to help avert the spread of preventable diseases” and “I believe that vaccines have negative side effects that outweigh the benefits of vaccination for children.”
The study did not find that people on the left were more likely to oppose or distrust vaccines. Rather, it found a highly nuanced result. The researchers examined two related but distinct contributors to right-wing ideology: self-identification as a political conservative and support for the free market. It found that while the former was related to somewhat more vaccine support, the latter was related to somewhat more vaccine opposition. According to Lewandowsky, the two opposing forces “virtually cancel overall.”
Other studies have found similar results. In a 2009 paper, Yale's Dan Kahan and his colleagues found that the conservative ideological values of “hierarchy” and “individualism” were both linked to greater opposition to the HPV vaccine in particular. In a paper from earlier this year, meanwhile, Kahan found that the idea of a link between the political left and the belief that vaccines in general are dangerous “lacks any factual basis.” In fact, if anything, he found a small increase in belief in vaccine risks as one moved to the right of the political spectrum.
If you'd prefer to examine the patterns of vaccine-preventable disease outbreaks, meanwhile, those also seem politically diverse. We are having a horrible year for measles, for instance, with 18 outbreaks and 592 cases, more than double the total in any previous year since 2001. And the 21 states that have seen cases and outbreaks run the political gamut; they include California and Massachusetts, but also Alabama, Tennessee, Texas, and Ohio (home to a large outbreak in the Amish community, a group of people that can hardly be called “liberal”). Last year, meanwhile, there was a measles outbreak clustered around a Texas megachurch.
So in sum, the evidence that vaccine opposition is somehow specially tied to left-wing beliefs is just lacking. Rather, the largest factor here, according to Lewandowsky's research, is conspiratorial beliefs, which are hard to categorize as either left wing or right wing in nature.