President Donald Trump signed an executive order on August 10 urging states to revise childhood vaccine recommendations, including splitting the combined measles, mumps and rubella shot into three separate single-disease injections, a proposal medical experts say lacks scientific basis and could leave children exposed to preventable diseases.
The order also recommends administering childhood vaccines at separate appointments wherever possible, rather than during a single visit. Health and Human Services Secretary Robert F. Kennedy Jr. was present in the Oval Office as Trump signed the document.
Public health specialists quickly raised concerns, warning that spacing out injections could increase the window in which an unvaccinated or partially vaccinated child might contract a vaccine-preventable illness before returning for a follow-up appointment.
A standalone measles-only vaccine is not currently marketed in the United States, and manufacturing separate single-disease shots at scale would require significant regulatory approval and production changes. Experts described the proposal as unlikely to materialize in the near term.
The signing was accompanied by several disputed statements. Trump claimed that “in many cases, we were requiring 72 jabs” for children, a figure health authorities say is misleading.
In 2025, the government’s childhood vaccination schedule recommended routine protection against 18 diseases. The number of separate injections between birth and age 18 varied depending on the brands used, the availability of combination shots and a child’s starting age, but generally totaled closer to three dozen, excluding annual flu and COVID-19 doses. Vaccines have also never been federally “required,” as mandates fall to individual states and school systems.
The combined MMR vaccine has been used for decades and repeatedly studied worldwide, with research consistently finding it safe and effective. Claims linking childhood vaccines to autism, repeated by members of the administration, have been investigated extensively and found to have no scientific support.
The measure marks the latest in a series of steps that have reshaped federal vaccine guidance. It follows an earlier directive to space out the timing of childhood immunizations against established CDC guidance, a shift that has drawn scrutiny from pediatric and infectious-disease organizations.
The executive order does not carry the force of law over states, which retain authority over school immunization requirements and vaccination policy. Its practical effect will depend on whether individual states choose to adopt the revised recommendations.
Medical bodies are expected to weigh in formally in the coming weeks, and the proposal is likely to face resistance from clinicians who caution that fragmenting or delaying established immunization schedules could erode protection against diseases such as measles, which has seen renewed outbreaks in several regions.