Sen. Bill Cassidy (R-La.) on Monday sharply criticized an executive order signed by President Trump that would split the measles, mumps, and rubella (MMR) vaccine into three separate doctor visits, arguing the president is overstepping his authority on a matter of public health.
“I’m a doctor. This executive order is wrong. The President does not have the expertise to make these changes,” Cassidy wrote on X shortly after the order was signed. “Vaccines are overwhelmingly safe. Vaccines are effective. Vaccines DO NOT cause autism.”
The Louisiana Republican, who is also a physician, warned that fragmenting the MMR shot would not reduce the number of injections children receive but rather increase them, potentially fueling parental hesitation and leaving kids more vulnerable. “Breaking up vaccines will mean children have to get more shots to get the same protection, not fewer shots. It will increase hesitancy and make children less safe,” he added.
The executive order follows a January initiative by the Department of Health and Human Services (HHS) to trim the list of recommended childhood vaccines, a move that was blocked by a federal judge in March. That earlier attempt, along with the latest order, builds on broader efforts by Trump and HHS Secretary Robert F. Kennedy Jr. to reshape the federal vaccination schedule, a push that has been driven in part by Trump’s repeated promotion of unsubstantiated claims linking rising childhood immunization rates to an uptick in autism diagnoses.
Cassidy’s rebuke is notable given his Republican credentials and his role on the Senate Health, Education, Labor, and Pensions Committee. He urged parents to rely on their pediatricians rather than the administration’s directives. “Parents should listen to their child’s pediatrician about vaccines rather than listening to an inaccurate executive order. This is so wrong,” he wrote.
The order has drawn immediate backlash from public health experts and lawmakers alike, who argue that altering the MMR schedule without scientific basis could undermine decades of progress in controlling measles, mumps, and rubella. Measles, in particular, is highly contagious and can lead to severe complications, especially in young children.
This is not the first time the administration has clashed with medical professionals over vaccine policy. Earlier this year, the release of internal communications from Dr. Anthony Fauci, the former top infectious disease official, reignited debates over COVID-19 vaccine guidance. Meanwhile, the administration’s broader efforts to overhaul federal health policies have faced legal and political hurdles.
As the story develops, Cassidy’s statement signals that even within the president’s own party, there is resistance to using executive power to override established medical standards. The White House has yet to respond to the criticism, but the order is expected to face further scrutiny in Congress and the courts.
