President Donald Trump has signed an executive order calling for sweeping changes to childhood vaccine recommendations, including fewer vaccines overall, replacing the combined measles-mumps-rubella (MMR) vaccine with separate shots, and administering all childhood immunizations during separate medical visits “to the maximum extent feasible.”
US Impact: Confusion and Delays
According to Dr Aaron Milstone of the American Academy of Pediatrics, the main outcome will be “confusion for parents,” with conflicting messages likely to delay vaccinations. During any delay, some children may be infected with deadly vaccine-preventable diseases. Measles cases are already at a 30-year high in the US.
The executive order has no immediate legal effect on the public, but it is likely to pressure US states to change requirements that children be vaccinated before attending school. It also sets the stage for legal challenges against states with their own vaccine recommendations.
Global Repercussions
Ben Kasstan-Dabush, assistant professor in global health and development at the London School of Hygiene & Tropical Medicine, said the recommendations are unlikely to be copied in other countries: “No country would want to deal with the inevitably costly outbreak responses that would occur as a result of this policy decision.”
However, ideas and diseases spread easily across borders. In the short term, parents in other countries may get the false impression that vaccines are unsafe and delay or avoid vaccination, putting their children at risk. The longer-term risk is that misinformation leads to lower vaccination rates at a population level, causing a resurgence of preventable diseases.
Prof Sir Andrew Pollard, director of the Oxford Vaccine Group, warned: “There is a risk of the confused messaging affecting people outside the US. Confidence in vaccines, and getting jabbed, is critical for the health of a population.”
WHO Defends Science-Based Schedules
Shortly after Trump’s announcement, the World Health Organization defended the science-based process used to set child immunization schedules worldwide. WHO spokesperson Tarik Jašarević told a press briefing in Geneva that it was important for countries’ vaccine schedule recommendations to be made by independent experts and “free of industry and political influence.” He added, “When these standards are not upheld, trust in vaccines, health experts and scientific institutions, like WHO, can erode.”
Motivations and Misinformation
Trump has repeatedly repeated discredited claims that vaccination causes autism, and appeared to make the same link when signing the order. US health secretary Robert F Kennedy Jr is a leading vaccination sceptic who has amplified misinformation for years; one study found he was the top “superspreader” of Covid-19 vaccine misinformation on Twitter (now X) in 2021. Kennedy has tried to reshape US vaccination schedules but has been blocked by a federal judge, which a White House official said was separate from the executive order.
In 2025, UK vaccine experts called on public health agencies to get “Kennedy ready,” arguing that “the political agenda against vaccination in the United States raises implications for routine childhood vaccination programmes in the United Kingdom and countries around the world, due to the transnational spread of diseases and ideas.”
Science Behind the Proposals
Helen Bedford, professor of child public health at UCL, said there is “strong evidence of no link” between the MMR vaccine and autism. “The vaccine has, and continues to save, millions of lives.” False claims of a link were made by British doctor Andrew Wakefield in 1998 in the Lancet, which was retracted, and Wakefield was struck off by the UK’s medical regulator. He has been lauded by anti-vaccination groups and attended Trump’s first inauguration.
On splitting the MMR vaccine, Bedford said, “The three vaccines have never been administered as separate doses to young children as part of vaccination policy so that policy’s safety and effectiveness are unproven. However, just by delaying protection it would be a serious step backwards for protecting our children’s health.” Kasstan-Dabush called it “an experiment with children’s health.” Adam Finn, emeritus professor of paediatrics at the University of Bristol, added, “Dividing the vaccine into separate components makes no logical sense and is infeasible at this time in any case as no such vaccines are available.”
Effect on Vaccination Rates
Studies of communities with low vaccination rates show that accessibility, such as logistics of getting children to appointments, plays a role alongside hesitancy. If parents can only get one shot per appointment, they may not return for the rest. Azeem Majeed, professor of primary care and public health at Imperial College London, said, “Spacing vaccines across many separate visits increases the likelihood of delayed or missed doses and leaves children susceptible for longer, with no demonstrated safety benefit in healthy children.”
