US President Donald Trump defended his recommendation to separate the combined measles, mumps and rubella vaccine despite acknowledging that he had no direct evidence supporting his suggestion that administering the three vaccines together could be dangerous.
WASHINGTON — US President Donald Trump defended his recommendation to separate the combined measles, mumps and rubella vaccine despite acknowledging that he had no direct evidence supporting his suggestion that administering the three vaccines together could be dangerous.
Trump spoke after signing an executive order establishing new childhood vaccine recommendations. The policy calls for separate measles, mumps and rubella shots once the individual products become domestically available.
Asked whether there was evidence for his description of the combined MMR vaccine as potentially lethal, Trump replied: “No.”
“What I’ve heard is that there are there are some people that say it is that way and I say, well, let’s say there’s a five percent chance of it, let’s split it up, let’s split it up,” he said.
Trump said he had heard that individually administered vaccines were safe but that combining them “can be explosive”.
The president also recommended giving childhood immunisations over several medical visits instead of administering multiple vaccines during one appointment.
Trump said he had followed that approach with his own children.
“I took my children for five different vaccinations,” he said. “I took them through five different visits to the doctor. Essentially, they get 20 percent each and I had no problem.”
Trump said the additional visits were inconvenient but predicted that spacing out vaccines would affect autism rates.
“It’s inconvenient, it’s five stops, but it’s something that I think will have a huge impact on autism,” he said.
Asked whether extra medical visits would result in additional co-payments for families, Trump promised assistance but announced no specific financial programme.
“We’re going to be working with them, and we’re going to work with the families, and we’re going to make sure everything works out cost wise very well,” he said.
The executive order recognises 11 diseases for which immunisation is recommended for all children. Vaccines for other diseases would be limited to designated high-risk groups or administered through shared decision-making between parents and clinicians.
Vaccinations against hepatitis B, influenza and COVID-19 are no longer recommended universally under the new framework.
Health and Human Services Secretary Robert F. Kennedy Jr. said federal agencies had launched studies examining vaccine safety and long-term health outcomes.
“We are comparing health outcomes in vaccinated versus unvaccinated children,” Kennedy said.
“We’re examining aluminum adjuvants, the timing of the hepatitis B vaccine administered during — vaccines administered during pregnancy, and outcomes ranging from allergies to autoimmune disease to autism and other neurodevelopmental disorders,” he added.
Kennedy said the National Institutes of Health had issued 13 research awards examining autism prevalence, causes, treatments and services. Five of those projects would include vaccines among the potential factors examined.
NIH Director Jay Bhattacharya called autism “a very complicated condition” and cautioned that answers would take time.
“It’s not going to be a simple answer,” Bhattacharya said. “Science takes time.”
Bhattacharya said the measles vaccine remained important, particularly in responding to outbreaks, but opposed excluding children from school because their parents made different vaccination decisions.
The order advises states to review school immunisation rules. White House domestic policy official Heidi Overton said 28 states had stopped following CDC recommendations since January 2026 and were developing their own policies.