President Donald Trump on Monday signed an executive order that makes recommendations about the childhood vaccine schedule and says that the measles, mumps and rubella (MMR) vaccine should be split into three separate shots.
For parents across the country, there's unlikely to be an immediate impact on vaccine access, and the executive order is likely to face legal challenges.
"Today, we're proud to officially announce the United States of America's gold standard childhood vaccination recommendations. And that has to do with many subjects, but including autism in particular," Trump said before signing the order.
The order is already sparking pushback from the medical and public health communities, which have continued to reiterate decades of studies showing the safety and efficacy of the childhood vaccine schedule and vaccines more broadly.
They commonly note that while the political landscape on vaccines has changed, the science has not.
"This executive order is part of a troubling pattern by the administration to attempt to unilaterally change vaccine guidance, particularly for children, rather than relying on the transparent, scientific review that has guided the U.S. childhood vaccine schedule for decades," said Dr. Jan K. Carney, president of the American College of Physicians.
The American Academy of Pediatrics predicts it would take a decade to create a separate vaccine for each part of the MMR vaccine.
Republican Sen. Bill Cassidy, who is a physician, called the order "wrong."
"I'm a doctor. This executive order is wrong. The President does not have the expertise to make these changes. Vaccines are overwhelmingly safe. Vaccines are effective. Vaccines DO NOT cause autism," Cassidy posted on X.
Trump said that children decades ago children received a "small fraction" of currently required vaccines.
"In those times, people were much healthier," Trump said, without citing specifics. Doctors point out that about 400 to 500 people died each year in the United States before the introduction of the measles vaccine and some 48,000 were hospitalized. Now, the number is close to zero, according to the CDC.
Measles was declared eliminated in the U.S. in 2000, but cases have crept back up in recent years with lower vaccine intake.
"And of course, the high rates of autism now observed did not exist. So, there's a reason for such epidemic rates of autism. And we're going to bring it back to much closer to where it was," Trump said.
The rates of autism have increased in recent decades, but doctors largely attribute this to better awareness and diagnosis of the condition.
Trump said while "we did not know exactly what the cause is with respect to autism, it is essential to our research efforts that we have the very best vaccine recommendations in the entire world."
Dozens of studies involving millions of people have not found an established link between vaccines and autism.
He called the order "a major victory for parents' rights, religious and constitutional rights, and for the gold standard science."
There will likely be no immediate effect on vaccine access -- the order requests reports from agencies in 90 days. And Trump said parents can still choose to get their children all vaccinations, if they wish.
Typically the Centers for Disease Control and Prevention provides recommendations as to which vaccines to receive and at what age, which often guide health insurance coverage. It remains unclear how this EO may potentially reshape those recommendations.
According to a White House fact sheet, the order recommends that "all children get immunizations to provide protection for 11 diseases -- a decrease from the 18 diseases recommended by the Centers for Disease Control and Prevention in 2024."
The CDC had previously reduced the number of recommended shots on the vaccine schedule, though the changes had been stayed by a federal judge in March. Medical organizations pushed back on the vaccine policy changes, noting that there was no credible scientific evidence to justify them.
The executive order will also recommend "separating out the combined MMR vaccine into three single-disease shots and recommends administering all vaccines during separate medical visits to give parents more options regarding the timing and frequency of this vaccine administration," according to the fact sheet.
The recommendation to split the MMR into three separate doses comes nearly a year after Trump posted on his social media platform that the vaccine should be broken up "INTO THREE TOTALLY SEPARATE SHOTS (NOT MIXED!)"
But a 2024 CDC article -- which was still on the agency's website Monday afternoon -- said that "[n]o published scientific evidence" pointed to "any benefit in separating the combination MMR vaccine into three individual shots."
Vaccines do not "overload" a baby's immune system. Even if babies receive several vaccinations in one day, their immune systems are under significantly more pressure from the bacteria and viruses they encounter daily in their environment, according to the CDC.
It is not accurate -- as Trump said -- that there is any vaccine that contains the same volume of liquid as a bottle of soda, or anywhere close. The average vaccine contains half a milliliter of fluid, about one-tenth of a teaspoon, according to Johns Hopkins.
"By signing this executive order the president is helping Americans who are asking questions, especially post COVID, about vaccine requirements, and opening up a dialogue to encourage public trust," a White House official confirmed.
The White House also said that it is still recommending the measles and polio vaccine.
Health and Human Services Secretary Robert F. Kennedy Jr. has long espoused skepticism about the safety of vaccines, including the potential for a link between shots and autism.
He and Trump made several unsupported claims about links between vaccines and autism at Monday's signing.
Kennedy cited a "dramatic increase" in autism rates for the change and attacked the assertion that there are more cases of autism because there is a higher awareness.
"Because if we were just noticing it more, we would notice it in older groups, but we're not differently noticing it in kids who were born around 1989 or after," he said. "The older generations are not seeing those generations. So something happened in the in the mid '90s that changed our children, and it has to be an environmental explosion because genes don't cause epidemics."
Major medical groups uniformly assert that there is no single cause of autism, but it is largely attributable to genetics and early brain developement. That the safety of vaccines has been studied for decades, and there is no known link to autism.
