Jon Stewart on Tuesday took aim at the Disneyland measles outbreak and the vaccine skeptics who make these types of outbreaks more likely to spread — even though the scientific evidence overwhelmingly shows vaccines are safe and don't cause autism.
Stewart responded to a clip of a California mom saying she denied some vaccines for her children. "Look, California, if your crazy wellness ideas only affected you, I'd be fine with that," Stewart said. "But your choice puts other people in jeopardy."
Stewart is referring to what's known as herd immunity, a coverage threshold that effectively prevents an illness from spreading. Vaccinated people essentially act as barriers to outbreaks, since diseases can't pass through them and infect other people. This barrier helps protect some of the most vulnerable populations: infants under 12 months of age, who can't get vaccinated and are more susceptible to infection, and the elderly, who have a higher risk of death if they contract these illnesses.
Stewart also mocked Sen. Rand Paul (R-KY) for insinuating that vaccines can cause "profound mental disorders." (Paul later walked back these comments.)
"Perhaps we should not have asked Dr. Rand Paul, who's heard things," Stewart said. "He's star of the hit medical drama, Dr. Paul: Anecdote Man."
The empirical research on this issue is clear: there is no connection between vaccines and autism. The Lancet, a British medical journal, in 2010 retracted a high-profile study from 1998 that falsely claimed to find a link between vaccines and autism, discrediting the one major piece of evidence vaccine skeptics cited in the past.
"The science is clear on it," Stewart said. "The only reason that we're even having this discussion is because of how well vaccines have worked. And they only work when we all do them."