Doctors say to ignore Trump as he cites hearsay to upend vaccines amid historic measles outbreak

President Donald Trump signed an executive order Monday seeking to remake the nation’s childhood vaccination recommendations, calling for vaccines to be administered during separate medical visits and for the eventual breakup of the combined measles, mumps and rubella vaccine — while making unsupported claims that the MMR shot could be “quite lethal” and “explosive.”

The order drew immediate condemnation from pediatricians, infectious disease specialists and other physicians, who said the changes lack scientific justification and could make vaccination more difficult as the United States experiences its worst measles outbreak in more than 30 years.

Dr. Demetre Daskalakis, an infectious diseases and immunizations expert who previously led the Centers for Disease Control and Prevention’s National Center for Immunization and Respiratory Diseases, told The Advocate that the change amounted to public health policy by vibes.

Related: Dr. Demetre Daskalakis on leaving the CDC and calling out RFK Jr.

“The new vaccine order from on high created through hearsay and based on the bad advice from the health Secretary and his conflicted advisors feels like Groundhog Day,” Daskalakis said Monday night.

“This is the same vaccine schedule reversed by the court, but is now chiseled on stone tablets,” he continued. “But this commandment only causes confusion since it is not real, implementable, or science-based. It reads as if it was written by someone who doesn’t know anything about public health or vaccines.”

The CDC center Daskalakis led was responsible for major federal immunization programs and vaccine-preventable disease work.

Trump’s order builds on earlier administration efforts to narrow universal childhood vaccine recommendations. The administration now recommends routine vaccination against 11 diseases while placing several others into categories for people at elevated risk or for “shared clinical decision-making,” in which a clinician and family determine whether vaccination is appropriate based on individual circumstances.

The order also says childhood immunizations should, “to the maximum extent feasible,” be administered during separate medical visits and calls for MMR eventually to be given as three single-disease vaccines once those products become available in the United States.

Those separate measles, mumps and rubella vaccines are not currently an option in the United States. Merck, which manufactures MMR vaccines, has said there is no published scientific evidence showing a benefit to splitting the shot and warned that requiring separate appointments could result in delayed or missed vaccinations, Reuters reports.

During Monday’s Oval Office event, Trump suggested that administering the three vaccines together could itself be dangerous. “Together, there could be a possibility they’re quite lethal,” Trump said.

When a reporter later asked what evidence supported that assertion, Trump did not cite a study or scientific authority.

“What I’ve heard is that there are some people that say it is that way,” Trump replied. “And I say, ‘Well, let’s say there’s a 5 percent chance of it. Let’s split it up. Let’s split it up.’”

Trump subsequently said, “I’ve heard when you put them together, they can be explosive.”

Decades of research involving millions of children have found no evidence that vaccines cause autism, despite Trump’s repeated focus on autism while discussing childhood vaccination. The American Academy of Pediatrics responded by emphasizing that its own childhood immunization schedule remains based on scientific evidence.

“The AAP’s childhood vaccine schedule is built on science. Families deserve facts, not fear,” the organization said in a social media post Monday.

Related: I’m a gay dad, and I’m furious at Donald Trump for scaring people about Tylenol

The group said its recommendations are based on decades of research, thousands of studies, continuous safety monitoring and the expertise of pediatric physicians and scientists. “We don’t change recommendations because of political considerations, speculations, or misinformation,” the AAP said.

The American Medical Association also warned that changing an established vaccination schedule without credible evidence risks undermining confidence in immunization and endangering children.

“Vaccines are among the most thoroughly studied, effective tools we have to protect children from serious vaccine-preventable diseases,” AMA President Dr. Willie Underwood III said. “Altering a proven vaccination schedule without credible evidence risks weakening public confidence and putting children’s health at risk.”

The Infectious Diseases Society of America issued a similarly forceful response.

“The American people deserve childhood vaccine recommendations that are made by qualified experts, through an established, transparent process and based on the best available scientific evidence,” IDSA President Dr. Ronald G. Nahass said in a statement. “Today’s executive order undermines all three of these fundamental standards.”

Nahass warned that making vaccination more complicated could reduce vaccination rates and leave children more vulnerable to measles and other preventable diseases.

One of the strongest political rebukes came from Louisiana Sen. Bill Cassidy, a Republican physician who chairs the Senate committee responsible for overseeing federal health agencies.

“I’m a doctor. This executive order is wrong,” Cassidy wrote on X. “The President does not have the expertise to make these changes.” He added that vaccines are overwhelmingly safe and effective and “DO NOT cause autism.”

Cassidy also warned that requiring more shots and visits would increase vaccine hesitancy and make children less safe.

Related: Texas's anti-LGBTQ+ attorney general sues Tylenol company over autism claims

“Parents should listen to their child’s pediatrician about vaccines rather than listening to an inaccurate executive order,” he said. “This is so wrong.”

Cassidy helped advance Robert F. Kennedy Jr.’s nomination for health secretary after publicly wrestling with Kennedy’s history of vaccine skepticism.

Daskalakis highlighted that history himself. In an Instagram story on Monday, he shared coverage of Cassidy’s criticism with the words, “This is his fault,” and asked, “How’s that vote Senator Cassidy? Tricked again?”

Daskalakis also expanded on his objections to the order, arguing that the administration’s effort to model the U.S. schedule on selected “peer countries” ignores differences among national health systems.

“The problem is that we aren’t peers with the countries cited — our healthcare system is not the same nor should our vaccine schedule be,” he wrote.

International vaccine schedules are not interchangeable. They are developed around differences in disease risk, health care systems, population vulnerability and how immunizations are delivered. The World Health Organization said Tuesday that vaccine schedules are based on decades of scientific research into when people are most vulnerable to diseases and when vaccines are most effective.

For Daskalakis, the administration’s action represents something more basic than a disagreement among experts.

“Sadly, the executive commandment changing the vaccine schedule without process or data is not shocking from this HHS and administration,” he wrote.

His advice to parents was simpler. “Parents should listen to their pediatrician and ignore this order. Vaccines work.”