President Donald Trump has signed an executive order aiming to revise federal guidance on childhood vaccinations and prompting states to re-examine school vaccine mandates. The order, titled the ‘Gold Standard Childhood Vaccine Recommendations,’ divides childhood vaccines into three categories and directs federal agencies to advance new recommendations.
A key provision of the order calls for breaking up the combined measles, mumps, and rubella (MMR) vaccine into three separate shots, a move driven by concerns about a now-debunked link to autism. The order also suggests that all childhood immunizations should ideally be administered at separate medical visits, to the maximum extent feasible.
Medical experts have long stated that the single MMR shot is proven safe and effective, and that splitting it could leave children unprotected against dangerous diseases for extended periods. The order acknowledges that previous vaccine directives have faced legal challenges and instructs federal agencies to pursue the new recommendations "to the fullest extent allowable by law."
However, the executive order is largely symbolic, as states, not the federal government, hold the authority over school vaccine mandates. Formal changes to the federal vaccine schedule would require a rulemaking process involving the Centers for Disease Control and Prevention (CDC) and its advisory committee.
The directive comes as measles cases are rising. The CDC has reported 2,465 cases across 47 states in 2026, surpassing the previous year’s total, with 93 percent of cases occurring in unvaccinated individuals. Childhood vaccination rates have fallen to 92.5 percent, leaving approximately 300,000 children vulnerable.
Decades of research have affirmed the safety and efficacy of the MMR vaccine, which is 97 percent effective in preventing infection. Adverse effects are rare, and there is no scientific evidence supporting any medical benefit from separating the vaccines.
The current CDC schedule recommends two doses of the MMR vaccine: the first between 12 to 15 months of age and the second between four to six years old. Under the existing schedule, vaccines are typically administered over multiple doctor visits during a child's first 18 months, at two, four, six, 12, and 15 months, with a few shots given at each visit to provide protection as early as possible. Experts maintain this schedule is carefully studied and safe.
The executive order does not present a specific revised schedule. Instead, it directs agencies to review and adjust the recommendations as deemed appropriate. This initiative builds upon a January announcement by the Department of Health and Human Services that reduced the number of vaccines recommended for all children from 17 to 11.
Under the administration's proposed advisory guidance, vaccines for 11 diseases, including measles, mumps, polio, and whooping cough, would still be recommended for all children. Vaccines for hepatitis A and B, and meningococcal disease, along with flu and COVID-19 shots, would be recommended only for high-risk groups or through shared decision-making between parents and doctors.
President Trump has expressed a belief that separating vaccines, particularly the MMR vaccine, could mitigate potential harm, stating, "Together, there could be a possibility [the MMR] is quite lethal and separately it looks like they are not at all lethal but very effective." He has also suggested that five separate visits for vaccines in a child's first year might be preferable to receiving them all on the same day, citing personal observations of "bad things happen[ing] in many cases" after vaccinations.
Despite these claims, there is no evidence suggesting the combined MMR vaccine is lethal. Serious side effects are exceedingly rare, and the risks associated with the vaccine are significantly lower than the risks of the diseases it prevents. Before the widespread use of the measles vaccine, an estimated 500 children died annually from measles in the U.S. Current CDC data indicates that about 1 to 3 out of every 1,000 children infected with measles may die from complications, whereas no deaths have been linked to the MMR vaccine in healthy individuals.
The doses of live viruses in vaccines like MMR are minuscule. Major medical organizations, including the American Academy of Pediatrics (AAP), generally follow schedules that align with a child's immune system development and do not support nonmedical exemptions. Dr. Sean O’Leary, chair of the AAP Committee on Infectious Diseases, stated that immunizations are designed to help the immune system recognize and fight serious diseases, are carefully tested, and that their pacing and combination are based on the understanding of when a child's immune system is best able to respond.
Trump’s emphasis on separating the MMR vaccine appears to stem from his long-held belief in a discredited theory linking childhood vaccines to autism. Despite extensive research finding no such link, he has publicly questioned the number of vaccines administered to children, framing it as a matter of "common sense" and stating his preference for separating vaccines, believing it to be "better."
A federal judge previously blocked similar changes in March, ruling that Health Secretary Robert F. Kennedy Jr. had unlawfully altered vaccine policy and improperly reconstituted the federal vaccine advisory panel. Over 40 studies involving more than 5.6 million people have found no correlation between the MMR vaccine, or any vaccine, and autism. The 1998 study that initially raised these concerns was retracted, and its author lost his medical license.
In late 2025, RFK Jr. directed the CDC to remove explicit statements from its website asserting that vaccines do not cause autism. The agency modified its text to highlight areas for further observation, drawing criticism from public health organizations. While the CDC notes an increase in autism diagnoses, this rise is attributed to broader diagnostic criteria, improved screening, and increased awareness, rather than vaccines.
Private insurers are still required to cover all ACIP-recommended vaccines at no cost, including those in the "shared clinical decision-making" category. Major health insurers have committed to continuing coverage for the current vaccine schedule through at least 2026, and some states have enacted laws mandating insurance coverage beyond federal requirements. The coverage requirement for HPV vaccines has been adjusted, with insurers no longer mandated to cover additional doses beyond a newly recommended single dose, although some plans may offer temporary coverage.