President Trump signed a sweeping executive order reducing the CDC's recommended childhood vaccines from 18 diseases to 11 and directing that the MMR shot be broken into three separate doses, drawing immediate pushback from medical groups and a fellow Republican.

Trump announced the order Monday from the Oval Office with Health Secretary Robert F. Kennedy Jr. at his side, calling it a "major victory for parents rights, religious and constitutional rights, and for the gold standard science." The order restructures how and when children receive immunizations, moves several vaccines, including COVID-19, hepatitis, and flu, to opt-in status, and directs the Department of Health and Human Services to develop a plan for offering separate measles, mumps, and rubella shots rather than the combined MMR vaccine used for decades, the Associated Press reported.

The order also advises states with school vaccine mandates to consider updating their laws to match the administration's preferred schedule and directs the Attorney General to challenge states that violate children's rights to religious or medical vaccination exemptions, Fox News reported. It recommends spreading vaccinations across five separate doctor visits rather than bundling them into fewer appointments.

Trump framed the move as giving families more control over their children's medical decisions. Trump spokesperson Kush Desai told the Associated Press that the president is "one of countless parents who have voiced questions and concerns about the combined MMR vaccine" and said the plan would "give parents more options on timing and frequency for their children," ultimately increasing vaccine uptake.

Sen. Cassidy breaks with Trump: 'The President does not have the expertise'

The executive order drew swift opposition from Sen. Bill Cassidy, the Louisiana Republican who chairs the Senate health committee and is himself a physician. Cassidy posted on social media within hours of the signing:

"I'm a doctor. This executive order is wrong. The President does not have the expertise to make these changes."

Cassidy's rebuke landed hard because it came from inside the president's own party and from a senator with direct jurisdiction over health policy. The New York Post noted that Cassidy also stated flatly that "Vaccines DO NOT cause autism," putting himself in direct conflict with the premise that has animated much of the administration's vaccine agenda.

The American Academy of Pediatrics struck a similar tone. Its president, Dr. Andrew Racine, said the announcement was spreading uncertainty, fear, and confusion where "there doesn't need to be any of that." Racine pushed back directly on the suggestion that the science had shifted:

"Science about vaccines and their efficacy has not changed. The distribution of viruses and other pathogens in our environment has not changed. Children in this country have not changed in the last 48 hours."

On the specific question of whether vaccines cause autism, a claim Trump has repeatedly suggested and Kennedy has championed, Racine was unequivocal. He said the potential link had been examined in "over 40 methodologically well-designed studies in over seven countries involving over 5 million children."

"I'm not sure that there is anything that has been as thoroughly looked at as this question. And the answer is unequivocally no."

Kennedy's overhaul already blocked once in court

Monday's executive order is not the administration's first attempt to reshape childhood vaccine policy. Last December, Trump ordered HHS to review how peer nations approach vaccine recommendations and consider revising U.S. guidance. Kennedy's department responded by cutting the number of vaccines it recommends for every child, a move a federal judge subsequently blocked.

Kennedy also fired an entire 17-member vaccine advisory committee and installed replacements who issued far more restrictive recommendations. A federal judge halted those changes as well. The new executive order includes several of the same schedule changes that courts have already stopped, raising an immediate question about whether the order will survive legal scrutiny any better than its predecessors.

Kennedy's tenure at HHS has extended well beyond vaccine policy. He and Dr. Mehmet Oz earlier revealed that over one million Obamacare enrollees lack Social Security numbers, a finding that raised serious questions about fraud in the federal health insurance marketplace.

Beyond those changes, Kennedy personally directed the CDC to abandon its longstanding position that vaccines do not cause autism, without supplying any new evidence to support the reversal. Changes to federal childhood vaccine recommendations customarily require approval from the CDC director, a process the executive order appears designed to circumvent or override.

That puts the newly Senate-confirmed CDC director, Dr. Erica Schwartz, in a difficult position. Schwartz previously oversaw policies promoting vaccination of service members while in a leadership role at the U.S. Coast Guard, a background that suggests she may not share the administration's skepticism toward the existing vaccine schedule.

Lawrence Gostin, a public health law expert at Georgetown University, said the Supreme Court's interpretation of presidential power may allow Trump to supersede Schwartz if she does not agree to the new recommendations. Gostin put it bluntly via email:

"This is clearly the first test for Dr. Erica Schwartz. The President is placing her in an untenable position."

No studies offered for splitting MMR into three shots

An unnamed White House official who briefed reporters on condition of anonymity said Trump was within his right to provide his own recommendation through the executive order and called the lawsuit blocking the health department's earlier schedule changes a separate issue. But when asked to provide any studies supporting the decision to split the MMR vaccine into three single-disease shots, the official did not supply any. The official said it was Trump's long-held view and that some countries provide individual measles vaccines in certain circumstances.

Trump went further than the order's text during the signing. He claimed the combined MMR vaccine could be "quite lethal," as Breitbart reported, telling those gathered:

"Together there could be a possibility they're quite lethal, and separately, it looks like they are not at all lethal, but just very effective."

Trump also expressed optimism about the broader approach. "I think you're going to see some amazing results [by] breaking it up," he said, adding that parents could still choose to give their children all vaccinations if they wish. "It's up to the parents, we're making recommendations that are strong, but it's up to the parents."

The administration's broader health agenda under Kennedy has produced a mix of policy outcomes. HHS recently moved to shut down a Kentucky organ procurement group after a federal review found patients showed signs of life, a decisive action that drew less controversy than the vaccine overhaul.

Kennedy, for his part, repeated his assertion in the Oval Office that he believes an unknown environmental factor is to blame for rising autism diagnoses. He said his department will deliver research findings "as soon as they are ready." At a Cabinet meeting last month, Trump publicly prodded Kennedy on the topic, asking, "How are you doing on the autism research?" Kennedy replied simply: "We will have an answer for you."

Vaccination rates already falling before the order

The executive order arrives against a backdrop of declining childhood vaccination rates nationwide. U.S. kindergarten vaccination rates have been dropping, and federal data show the share of children with vaccine exemptions rose to an all-time high during the 2024-25 school year. The country also faces a measles outbreak that could threaten its elimination status.

Studies of babies and toddlers in the United States have shown that using combination shots for childhood vaccines, rather than single ones, increased the likelihood that children completed all recommended vaccinations by age two. Splitting the MMR into three separate shots at three separate visits, as the order calls for, could reduce completion rates further at a time when they are already declining.

The Washington Examiner reported that the signing took place at the White House around 2:45 p.m. Washington time. Trump credited Kennedy and other health officials for helping shape what the administration titled the "Gold Standard Childhood Vaccine Recommendations."

Trump has long faced internal Republican friction on policy priorities beyond health care. His legislative agenda has encountered resistance from within his own caucus, as seen in recent struggles to advance the SAVE America Act through a divided Senate.

Meanwhile, the Make America Healthy Again agenda Kennedy has championed has produced some tangible results outside the vaccine debate. Major food manufacturers have responded to public pressure on ingredients, with Nestlé completing the removal of synthetic dyes from its U.S. products, a change that aligns with the broader push for cleaner food and health standards.

Parents deserve options, and the instinct to question a one-size-fits-all medical schedule is not unreasonable. But an executive order that overrides established medical guidance, offers no new studies to justify the change, and has already been blocked once in court is not parental empowerment, it is policy by assertion, and children's health is too important for that.