Donald Trump has signed an executive order that calls for sweeping changes to childhood vaccination policies in the US, including reducing the number of recommended vaccines and splitting the combined measles, mumps and rubella (MMR) vaccine into separate shots. However, experts say the order is likely to cause confusion rather than improve public health, and some of its proposals are currently impossible to implement.
What Does the Executive Order Propose?
The executive order, signed on Monday, directs revisions to the childhood vaccine schedule, with a particular focus on the MMR vaccine. It recommends that the combined MMR shot be replaced with separate vaccines for measles, mumps, and rubella, administered during different medical visits. Yet, no stand-alone vaccines for these diseases are licensed in the US, making this recommendation unenforceable at present.
According to Dr David Diemert, professor of medicine and director of the George Washington University Vaccine Research Unit, "the biggest impact of this executive order is that it's going to cause more confusion. And confusion for things like vaccination schedules for kids is never a good thing."
Impact on Vaccine Schedule and State Policies
Dr James Campbell, chair of the committee on infectious diseases for the American Academy of Pediatrics (AAP), clarified that the executive order does not "change anything about current recommendations." The Centers for Disease Control and Prevention (CDC) sets federal vaccine recommendations, not the president. However, the order pressures states to alter their policies, and as of January 2026, at least 28 states and the District of Columbia have announced they will follow vaccine recommendations from other entities, mostly the AAP.
Dr Sallie Permar, chair of pediatrics at Weill Cornell Medicine, advises parents to "absolutely proceed with getting their child's vaccines as currently recommended, and explore any questions with their pediatrician." Dr Katherine Piwnica-Worms, system chief of pediatrics at NYC Health + Hospitals, affirmed that AAP guidelines "will be what we continue to follow. We know these are backed by decades of studies, studying millions of patients, showing the vaccine schedule is safe and effective."
MMR Vaccine: Safety and Efficacy
The MMR vaccine protects against measles, mumps, and rubella, all highly contagious viral infections. Measles can cause severe complications like pneumonia and brain swelling, leading to hospitalization or death, especially in young children. While measles was declared eliminated in the US in 2000, cases are rising, with approximately 2,465 confirmed in August alone, linked to falling immunization rates.
Trump claimed during the signing that the combination vaccine could be "quite lethal," but Dr Permar stated that "decades upon decades of data and real-world expertise show otherwise," describing the MMR vaccine as "among the most life-saving of all vaccines." The AAP notes there is no evidence that separating the shots is safer; instead, longer intervals between doses can leave children vulnerable to preventable diseases.
Why Is the MMR Vaccine Combined?
The combined vaccine was developed in 1971, with children typically receiving the first dose at 12-15 months and the second at 4-6 years. Combination vaccines reduce the number of shots and appointments, which increases vaccination rates. Dr Diemert explained, "We know that the more injections you include in a schedule, the less likely a child is going to get fully vaccinated."
Extensive research confirms the MMR vaccine's safety. A 2020 Cochrane Review found it effective, safe, and unrelated to autism. The original study suggesting a link was discredited. Dr Campbell noted, "There's never been any data to support that vaccines cause or contribute to autism, but there have been many studies showing no association with autism."
Other Vaccines Affected and Expert Concerns
The executive order also recommends limiting vaccinations for hepatitis A, hepatitis B, influenza, meningitis, RSV, and rotavirus to high-risk children or case-by-case decisions. However, Dr Piwnica-Worms says all children benefit from these vaccines, not just those at high risk. Dr Permar highlighted the RSV vaccine as a "success story of American ingenuity," noting it has decreased infant hospitalizations since approval in 2023.
Despite the order, the CDC and AAP still recommend routine vaccination against 18 diseases for all children. The AAP's 2026 schedule remains endorsed by 12 health professional societies. Dr Campbell warned that the order could confuse parents, leading to lower immunization rates, especially since measles cases are at their highest since 1991. He noted that when Kennedy attempted similar changes in January, there was "a large rise in questions and hesitancy from families."
While Dr Diemert acknowledged a possible silver lining in sparking conversations about vaccines, he added, "I'm struggling to think of a positive."
