Jon Stewart dove headfirst into the vaccine debate on Tuesday night’s “Daily Show,” noting that it’s one of the few issues that bring Americans on both sides of the political spectrum together.

“Vaccine ignorance seems to have created some strange hospital bedfellows, uniting the fringe of left and right,” Stewart said. “Y’know, it makes me realize, there’s no red America, there’s no blue America. There’s just a needlessly sick America.”

As examples, Stewart played a clip of a woman from Marin County, Calif., attempting to explain the anti-vaccination sentiment.

“We live here in Marin County which is a liberal place. It’s a well-educated group of people,” she said. “It’s a thoughtful group of people. I think if parents are choosing not to vaccinate, it’s probably for a reason. “

Stewart dismissed her as having “mindful stupidity.”

Next, Stewart played a clip of Sen. Rand Paul (R-Ky.) claiming he knew of children who were vaccinated and “who wound up with profound mental disorders.” (Paul later clarified that he actually supports vaccination.)

So how do you explain the need for vaccines in a way everyone can understand? Stewart turned to zombie movies, where everyone has to try to board up an old farmhouse to keep the zombies out.

Check it out in the clip above.