>> Hi, my name is Paul Offit. I'm talking to you today from the Vaccine Education Center at Children's Hospital Philadelphia. It's November 20th, 2025. Well, yesterday, November 19th, 2025, the CDC did something remarkable, which is the website labeled “Vaccines and Autism” was changed to include a series of bogus and misleading claims that vaccines might cause autism. Previously, the website made it very clear by citing many different studies that vaccines don't cause autism.

But now that Robert F. Kennedy Jr. is the Secretary of Health and Human Services, a man who for 20 years has been an anti-vaccine activist and science denialist, he now is using the CDC as a weapon in his fight or war against vaccines. He's weaponized the CDC’s website to conform with Children's Health Defense’s anti-vaccine views. 

The most important thing that was said at the beginning of this new, revised website is that the CDC and researchers and public health officials have not “ruled out the possibility that vaccines could cause autism.” So, let's go look at that statement. Is it possible? Is it possible to rule out the possibility? 

Well, in order to answer that question, you need to understand how the scientific method works. The way it works is let's suppose you're a researcher, and you want to determine whether or not the MMR vaccine causes autism. You form a hypothesis, and in this case it's the null hypothesis. MMR vaccine does not cause autism. That's the null hypothesis. So, you do your studies. You can do one of two things with that null hypothesis; you can reject it or you can not reject it, but you can never accept it, or said another way, you can never prove never. 

So, at this point, there have been 24 separate studies, done in seven countries, on three different continents, involving thousands and thousands of children, and costing millions of millions of dollars. And every study has shown the same thing. You are not more likely to develop autism if you got the MMR vaccine or if you didn’t. But RFK Jr. is right that that doesn't prove it. 

You could have done a 100 studies, a 1,000 studies, a million studies, but you can never prove never. I'll give you another example. When I was a little boy in the 1950s, I used to watch the television show Superman starring George Reeves; that was before Christopher Reeve, who became the later Superman. But on that show, Superman flew. I mean, he had a cape behind him. He put his hands in front of him with this interlocking thumb grip, and he flew. And when you're 5 years old, television doesn’t lie. So, I went into the backyard, tied a towel around my neck, and then put my hands in front of me, after climbing on a small chair, and with the interlocking thumb grip, I put my hands in front of me and tried to fly, unsuccessfully. That didn't prove I couldn't fly. I could have tried a million times. Each time would have made it all the more statistically unlikely. 

You can't prove that I've never been in Juneau, Alaska, even though I've never been in Juneau, Alaska. You can just show a series of pictures of buildings in Juneau with me not standing next to them. 

So, when RFK Jr. sort of weaponizes the notion that you haven’t proven that vaccines can’t cause this possibility of autism, he's really misunderstanding the way that the scientific method works. He should also, in fairness, show that chicken nuggets haven't been proven not to cause autism. But the fact remains that measles, mumps, rubella vaccine doesn't cause autism. Vaccines don't cause autism. And I can't fly.