There is no link—none—between vaccinations and autism. There is a direct link between people not vaccinating their children and the rise in deaths from whooping cough.

For the most part conspiracy theories—those paranoia-based fantasies surrounding just about every major event in the last hundred years—are silly and harmless. You can go ahead and believe that the moon landing was faked. You’re a fool, and you’re wrong, but go ahead and believe it. But the conspiracy theories that claim there’s a link between vaccines and autism aren’t just silly. People are dying as a result of a theory that has been as roundly and thoroughly refuted as it is humanly possible to do. And now, thanks to the popularity of those misguided theories, pertussis—or whooping cough—which was nearly wiped off the face of the earth in the ‘70s and ‘80s, is making a huge comeback. And people are dying.

The history of the anti-vaccine conspiracy dates back to 1998, when a now-discredited study was published in the British medical journal The Lancet that suggested that certain childhood vaccines caused autism. Soon thereafter, former Playboy model Jenny McCarthy began speaking out about the link between vaccines and autism, and the anti-vaccine movement began to spread.

It didn’t matter that The Lancet repudiated the study, or that the study’s author admitted that his study was flawed (he consequently lost his medical license), or that no other researcher was ever able to replicate the results of the original study, because conspiracy theorists are immune to facts. Unfortunately, human beings are not immune to certain illnesses, and as increasing numbers of parents began foregoing their children’s immunizations, certain diseases once thought to be eradicated began to reappear.

In the case of the latest whooping cough outbreak, researchers have found that incidences of whooping cough are 10 –100 times higher in areas where anti-vaccine movements influenced vaccination numbers.

“The methods employed in this study only demonstrate trends, not precise comparisons,” one study concludes. “Nevertheless, it emphasizes that public perception of vaccine risks—even if not supported by scientific evidence—can deter immunization acceptance with tragic consequences.”

So even though it’s been proven that there is no link—none—between vaccinations and autism, there is a direct link between people not vaccinating their children and the rise in deaths from whooping cough.

As a recent article in Forbes concluded, “The highest rate of infection in the nation is in Wisconsin (which has also been hit hard by anti-vaccine effects), followed by Washington and Montana. Ten deaths have been reported, mostly in infants who were too young to be vaccinated. For all this, we can thank the anti-vaccination movement.” 

So believe what you want about who killed Kennedy, or who really caused 9/11, or whether there were alien autopsies conducted at Area 51. The relative insanity of your theories affects no one but the people who are forced to listen to you rant. But when it comes to immunizations, your misinformed paranoia actually matters.