“Just the other day, two years old, two and a half years old, a child, a beautiful child went to have the vaccine, and came back, and a week later got a tremendous fever, got very, very sick, now is autistic.”

Donald Trump knows what he’s doing. He told this story during the Republican presidential debate Wednesday night, after CNN moderator Jake Tapper asked about his history of linking vaccines to autism.

That link does not exist. It has been disproven and debunked over and over and over. The very idea stems from a single 17-year-old study that was retracted.

Arguing with Donald Trump is not interesting. He is wrong. What’s interesting is why anti-vaccine sentiment endures in the face of overwhelming evidence, and the cultural factors that have led us to a point where vaccines are being litigated during a presidential debate.  

I say Trump knows what he’s doing, because a story like the one he told is more affecting and persuasive than just presenting the facts. Last year, Vanessa Wamsley wrote in The Atlantic about how personal stories of vaccination experiences have more sway than medical information from a physician, or from the Centers for Disease Control and Prevention.

One skeptical mother she interviewed said:

“Right now, the people telling their personal stories influence me more. I feel like the data could be flawed for one reason or another, but I feel like someone’s story, because they’ve gone through something, and they don’t want other people to go through it, I feel like I trust that more.”

Informing people about vaccines, and trying to expose misconceptions, can backfire. One study showed that people were actually less likely to get a flu shot after being told it does not cause the flu.

Much of the distrust of vaccines seems like it can be attributed to a fear of the “unnatural” and a distrust of institutions. The latter that was invoked during Wednesday night’s debate—not by Trump, but by Ben Carson.

Tapper asked Carson, a pediatric neurosurgeon, if he thought Trump should stop saying disparaging things about vaccines. Carson, to his credit, immediately said, “There have been numerous studies, and they have not demonstrated that there is any correlation between vaccinations and autism.”

But still he distanced himself from a strong pro-vaccine stance. “Vaccines are very important,” he said. But then he started to walk it back. “Certain ones. The ones that would prevent death or crippling. There are others, there are a multitude of vaccines which probably don’t fit in that category, and there should be some discretion in those cases. But, you know, a lot of this is—is—is pushed by big government. And I think that’s one of the things that people so vehemently want to get rid of, big government.”

Now suddenly, the question of whether you should trust vaccines is framed around whether or not you trust the government. This is a very Republican take on vaccine skepticism, which has largely been portrayed as the domain of hippie liberal mothers who distrust modern medicine.

In Eula Biss’s excellent book on vaccination fear, On Immunity, she writes about talking to mothers who are skeptical of vaccines.

“The fact that the press is an unreliable source of information was one of the refrains of my conversations with other mothers, along with the fact that the government is inept, and that big pharmaceutical companies are corrupting medicine,” she writes. It’s not hard to see how a skepticism of vaccines could stem from a fear of these big faceless institutions, and from a resistance to being told what to do.

“Vaccines are regulated, recommended, and distributed by the state—there is a very literal relationship between government and vaccination,” Biss writes. “But there is a metaphoric relationship too. Vaccines govern the immune system, in the sense that they impose a particular order on it … We resist vaccination in part because we want to rule ourselves.”

That's why, though Carson defended the medical merits of vaccines, his nod toward big government  may have ended up stoking the very fire of fear that Trump lit.