Study Finds Widespread Belief in Measles Misinformation

As the U.S. is in the middle of one of the worst measles outbreaks in years, with more than 800 confirmed cases nationally and more than 600 cases in Texas alone, a new report from KFF, formerly known as the Kaiser Family Foundation, found that more and more Americans have heard false claims about the disease and the vaccine that can effectively prevent it.

The poll conducted in April 2025 found that nearly two thirds of U.S. adults have heard or read that getting the measles vaccine is more dangerous than an actual measles infection, which is an increase of 15 percentage points compared to March 2024, when a similar survey was fielded. Moreover, almost two thirds of U.S. adults have heard that the measles, mumps and rubella vaccines (MMR) have been proven to cause autism in children – a claim that a group of leading autism advocacy organizations rebutted in a joint letter published last week. “Vaccines do not cause autism,” the statement reads. “Decades of scientific research confirm there is no causal link. Public health messaging must be grounded in science and protect all communities.”

While coming across false information is one thing, believing it is another story. And yet, KFF found that a worryingly large number of Americans believe in the false claims proliferated on the internet and, at least in the past, made by Robert F. Kennedy Jr., a known vaccine critic and now the country’s health secretary. 25 percent of respondents said that they thought it was definitely or probably true that the MMR vaccine causes autism, while 19 percent believe that getting vaccinated is more dangerous than a measles infection. 24 percent think it’s likely true that vitamin A can prevent measles, a claim that is also not backed by science. While it’s true that measles can cause vitamin A deficiency in which cases supplementation is recommended, it does not treat the more severe symptoms of measles, nor does it help prevent infection in the first place.

The study also shows a large partisan gap in measles beliefs. Republicans are much more likely than Democrats to believe in any of the three false claims covered in the survey. Interestingly, parents also showed an above-average tendency to believe in measles misinformation, which is a potentially dangerous development, given that parents are the ones to decide whether their children get vaccinated or not.

Partisanship aside, KFF found a lot of uncertainty with respect to measles and measles vaccines. For each of the three claims, at least half of respondents fell into the “malleable middle”, i.e. the group either saying that the claims are “probably true” or “probably false”. These people are potentially receptive to mis- or disinformation, which is why it is important for officials not to undermine the scientific consensus, which would sow even more uncertainty and doubt.