GOP Doctor Denounces Trump's 'Crazy' MMR Vaccine Claims After Confirming RFK Jr.

Bill Cassidy is a medical doctor. He is also a Republican senator from Louisiana, and in early 2025, he voted to confirm Robert F. Kennedy Jr. as the nation's health secretary—a man whose career has been built on promoting the idea that vaccines cause autism, a claim that has been thoroughly debunked and that cost Kennedy credibility in mainstream medicine decades ago. On Sunday, speaking to CNN, Cassidy denounced the president's recent statements about the MMR vaccine as "crazy" and "stupid."

The occasion for Cassidy's rebuke was Trump's decision to alter the childhood vaccination schedule. The president, with Kennedy at his side, had ordered that the combined measles, mumps, and rubella vaccine be replaced with three separate shots—doubling the number of injections required. Trump's language was extreme. He called the combined MMR vaccine "sort of like a nuclear weapon" and suggested it could be "quite lethal." When asked whether harm might come from requiring parents to administer six separate shots instead of two, Trump said nothing bad could happen.

Cassidy's response was measured but pointed. He walked through the practical consequences with the clarity of someone who understands both medicine and logistics. Instead of two doctor visits, parents would now need six. Instead of two needle sticks, their children would receive six. The insurance system would absorb the cost of six visits instead of two, ultimately raising premiums for everyone. "The president is wrong," Cassidy said. "There's a lot of bad things that will come out of this."

The irony of Cassidy's position is sharp and uncomfortable. He had voted to confirm Kennedy despite knowing exactly who Kennedy was—a man who has spent decades pushing the false theory that vaccines cause autism. When Cassidy announced his support for Kennedy's confirmation, he acknowledged that pediatricians across the country opposed the nomination precisely because they spend their professional lives combating vaccine misinformation. Cassidy extracted what he believed was a safeguard: Kennedy promised that the CDC would not remove its statement that vaccines do not cause autism.

That promise lasted only as long as Kennedy's first weeks in office. The CDC's autism and vaccines page was altered. The headline "Vaccines do not cause Autism" now carries an asterisk. The footnote beneath it suggests that the root causes of autism remain unknown—technically true but misleading in context. New text was added to the page, including two "key points" designed to appeal to vaccine skeptics. One claims that the statement "vaccines do not cause autism" is not evidence-based because studies have not ruled out the possibility. The second suggests that studies showing no link between vaccines and autism may have been suppressed by health authorities.

Cassidy's critics have noted the contradiction. He has continued to cast crucial votes for Trump's nominees even as he has publicly objected to the president's policies. In August, he cast the deciding vote to confirm Todd Blanche, a former criminal defense lawyer for Trump, as attorney general. He has also clashed with Trump over the ongoing Iran war. Yet he keeps voting yes.

The senator's position on the vaccination schedule change is scientifically sound. The MMR vaccine has been studied extensively and shown to be safe. The claim that it causes autism originated in a single fraudulent paper that was retracted. No credible evidence supports the theory. Separating the vaccine into three shots provides no medical benefit and creates only logistical burden and expense. Cassidy's warnings about the practical harms are accurate.

But his denunciation of Trump's claims, however correct, arrives after he has already helped place the man most responsible for spreading those claims in charge of the nation's health apparatus. The question now is whether his Sunday morning criticism will translate into any meaningful action—or whether it will simply be another instance of a Republican senator speaking out while continuing to enable the very policies he criticizes.