Head to the Centers for Disease Control and Prevention (CDC) website, and it's written in bold text: vaccines do not cause autism.

Even so, an incredible 24 percent of US adults think the opposite when it comes to the MMR (measles, mumps, rubella) vaccine. Another 3 percent aren't sure.

The stats are based on a survey of 1,522 people carried out by the Annenberg Public Policy Center (APPC) at the University of Pennsylvania last April, fuelling concerns that the false beliefs will lead to fewer vaccinations and put a far greater percentage of the population at risk of preventable diseases.

More than a quarter of a century has passed since the former physician Andew Wakefield famously published a fraudulent study linking autism spectrum disorder with MMR vaccines. Though the paper has since been retracted, the APPC team suggests the echoes of the ensuing debate continue to sow concern and confusion.

"The persistent false belief that the MMR vaccine causes autism continues to be problematic, especially in light of the recent increase in measles cases," says Kathleen Hall Jamieson, director of the Annenberg Public Policy Center.

Misinformation around COVID-19 vaccines doesn't seem to have helped either.

Study after study has demonstrated that vaccines, and the ingredients in vaccines, aren't linked to autism. What we also have evidence of is that vaccines are responsible for saving hundreds of millions of lives in recent decades.

Vaccines are responsible for virtually eliminating diseases such as smallpox, polio, diphtheria, and mumps. Until the recent surge, measles was also virtually eliminated. Far from an innocuous childhood illness, the measles virus causes fever-like symptoms which can lead to complications such as blindness and brain damage. In the worst cases, it can be fatal.

"Our studies on vaccination consistently show that the belief that the MMR vaccine causes autism is associated not simply with reluctance to take the measles vaccine but with vaccine hesitancy in general," says Jamieson.

Almost 6 in 10 respondents to the survey knew that measles can spread through coughing and sneezing, and via contaminated surfaces. However, more than half were unsure about the incubation time for measles (when a person is infectious, before the rash starts), which can be up to four days.

The only scenario where health experts recommend against the MMR jab is when it's for pregnant women. Because the vaccine contains a weaker version of the measles virus, it can theoretically harm the baby. There's no risk to babies in the womb from mothers who've had the MMR jab at least a month before becoming pregnant.

Cases of measles are on the rise in the US and across the world, with the vast majority of infections occurring in children who are unvaccinated or whose vaccination status isn't certain. The US has seen 146 cases in 2024 up to and including May, compared with 58 in the whole of 2023.

Experts and health professionals are continuing to work on vaccine education, and overcoming vaccine hesitancy, but the reality is sobering: distrust of vaccines can lead to illnesses and deaths that were easily preventable.

You can read an outline of the survey results online here.