The only person who ever basically said that vaccines cause autism was Andrew Wakefield and he was a con artist who was trying to sell his special magic don't give you autism vaccine, which turned out to be the same stuff as the "autism vaccine" or in some cases saline.
He had his medical licence revoked. He should have gone to prison.
Only morons believed him, and only morons continue to believe him.
I suspect they mean the only person with any kind of "scientific" presentation, and everything after that has been a game of telephone amongst the anti-vax crowd.
Disgraced, former Doctor, Andrew Wakefield originally did the report that the MMR vaccine had numerous issues.
He would go on to say that it is better to get the vaccines separately.
It would later be found that he was making 10s of millions selling test kits.
The link between autism and the MMR vaccine wasn't even direct. It was claimed that the MMR vaccine caused bowel inflammation, which then caused autism.
Real wackadoo science. Not sure how anyone believed it. We are seeing something similar with the aluminum causes cancer and dementia crowd.