US President Donald Trump has signed an executive order calling for a reduction in the number of vaccines recommended for children and urging that the measles, mumps and rubella (MMR) vaccine be administered as separate shots.
Trump has repeatedly questioned the safety of childhood vaccines and has promoted a discredited claim linking the MMR vaccine to autism. However, multiple scientific studies have found no evidence that vaccines cause autism.
Under the new order, the number of vaccines recommended for all children would fall from the 18 currently recommended by the American Academy of Pediatrics to 11.
The vaccines covered include those against measles, mumps, rubella, diphtheria, tetanus, pertussis, polio, Haemophilus influenzae type B, pneumococcal disease, human papillomavirus and chickenpox.
Trump also argued that children should receive their vaccinations over several visits rather than receiving multiple shots during the same appointment.
The president suggested that administering the MMR vaccine as a combined shot could be dangerous, but when asked to provide evidence for the claim, he acknowledged that it was based on what he had heard.
Health experts have strongly criticised the proposal. The US Centers for Disease Control and Prevention says the MMR vaccine is generally safe and that most people who receive it do not experience serious problems. It also says vaccination is safer than contracting measles, mumps or rubella.
The CDC further states that there is no published scientific evidence showing a benefit from separating the combined MMR vaccine into three individual injections.
Experts have warned that separating vaccines could increase the number of medical appointments children need and make it more difficult for parents to complete recommended immunisation schedules. They also say delaying vaccinations could leave children vulnerable to preventable diseases.
Dr William Schaffner of Vanderbilt University School of Medicine said the proposed approach would create additional costs and logistical difficulties without providing a proven medical benefit.
The American Academy of Pediatrics has also opposed the changes. Its president, Dr Andrew Racine, described the order as dangerous and said it was not supported by high-quality scientific evidence.
“Delaying or skipping shots is risky, especially as measles continues to spread and children go back to school,” Racine said.
Republican Senator Bill Cassidy, a physician who supported the confirmation of Health Secretary Robert F Kennedy Jr, also criticised the order, saying vaccines are overwhelmingly safe and effective and do not cause autism.
The controversy comes as Kennedy, who has previously expressed doubts about aspects of vaccine policy, continues efforts to change federal vaccine regulations. Kennedy has said the administration’s proposed changes are intended to give parents greater choice rather than prevent access to vaccines.
The CDC currently recommends two doses of the combined MMR vaccine for children, with the first dose given between 12 and 15 months and the second between four and six years of age.
Research has repeatedly found no connection between the MMR vaccine and autism. A major Danish study published in 2019 examined more than 650,000 children and found no evidence that MMR vaccination caused or triggered autism.
Trump’s order also calls for research into alternatives to aluminium compounds used in some vaccines. The American Academy of Pediatrics says the small quantities of aluminium salts used in vaccines have not been shown to pose significant health risks and are used to strengthen the body’s immune response.
Because school vaccination requirements are largely determined at the state level, Trump’s order serves primarily as federal guidance rather than directly changing the vaccines children must receive to attend school.
Medical experts remain concerned that changes to vaccination recommendations or increased public doubt about vaccines could reduce immunisation rates and contribute to the return of diseases such as measles.
