Vaccines are completely safe, unless your definition of dangerous includes a slight fever or a little soreness. The chances of any given child having a severe allergic reaction to a vaccination is about one in one million, which is about 100 times less likely than that child getting struck by lightning. It has been proven time and time again that there is absolutely no basis for the claim that vaccines are related to autism or any other developmental disorder.

Yet a disturbing number of people in America seem to believe otherwise. This faulty belief is contributing to the current proliferation of the measles on the West Coast, which boasts a distressingly low vaccination rate.

How did we get here? We have one person in particular to thank for sparking the anti-vaccination movement: Andrew Wakefield.

Wakefield published a study in 1998 that confirmed a causational relationship between the administration of MMR vaccines and the development of autism. The Lancet, a widely respected medical journal, published his findings and ignited a firestorm. Wakefield’s findings directly contributed to a steep drop in vaccination rates and the public perception of vaccines as potentially dangerous.

Unfortunately for The Lancet, Wakefield had fabricated his data and skewed it in a way to fit his narrative. Somehow this passed the peer review process of The Lancet, resulting in one of the biggest PR disasters in medical journal history. The study was completely and thoroughly discredited and was retracted by The Lancet in 2004. Eventually, Wakefield was stripped of his medical license.

If the study was discredited more than a decade ago—and so many other studies show the vaccine is safe—why are we still talking about it?

Television star Jenny McCarthy, whose son has autism, believes in a link between vaccination and her son’s disease, and has used her fame into a platform from which to proselytize the possible danger. Even our politicians are (disturbingly) not immune to misinformation, as Rand Paul proved last week, or Dan Burton, an ex-Congressman who had actually chaired hearings on vaccinations and autism, demonstrated in an interview with Anderson Cooper. The continued influence of the movement sparked by Wakefield’s study has led to lower US measles vaccination rates than that of more than 100 other countries.

With the recent resurgence of the measles, a strong counter-movement has arisen. Many are now demanding their school districts to require vaccinations. Many doctors are pressuring patients to get their children vaccinated. In California, lawmakers are going so far as to remove the ability for personal belief exemptions for vaccines. Will the pro-vaccination pushback be enough to change the minds of the anti-vaccine crowd? Or will it take an actual outbreak of a formerly eliminated disease?