When Donald Trump signed an executive order on Monday to scale back the list of universally recommended childhood vaccines, the decision was framed as a matter of parental choice. But public health officials across Europe are watching with alarm, warning that the ripple effects could reach far beyond American borders.
The order removes COVID-19, influenza, rotavirus, meningococcal disease, RSV, and hepatitis A and B from the routine childhood immunisation schedule. Some of these vaccines would still be offered to children deemed at higher risk, while others would be left to "shared clinical decision-making" between parents and doctors. The directive also calls for splitting the combined measles, mumps and rubella (MMR) vaccine into three separate shots, administered at different visits—a move that runs counter to decades of vaccine science and practice.
Marco Cavaleri, head of the European Medicines Agency’s Public Health Threats Department, described the potential consequences in stark terms. Skipping routine childhood vaccinations could be "catastrophic," he told Euronews, risking "the return of diseases that we were able to contain and eliminate from our countries." He also warned that such decisions "could be very detrimental in terms of vaccine confidence."
The order arrives amid a broader assault on vaccine science from within the US administration. Health Secretary Robert F. Kennedy Jr. has long questioned vaccine safety and promoted unsubstantiated links between vaccines and autism. The World Health Organization’s director-general, Tedros Adhanom Ghebreyesus, pushed back on Wednesday, stating on X that "the current evidence is unequivocal: vaccines—including the MMR vaccine—are safe and do not cause autism."
A step backwards for immunisation science
Combination vaccines have been a cornerstone of modern paediatrics, reducing the number of injections children need and simplifying schedules for families and healthcare systems. The global trend has been toward more combination vaccines, not fewer. Cavaleri noted that the US decision "is going against what the future is going to bring to us in terms of getting better protection for children, adults and the elderly," adding that "there is no scientific basis to split these vaccines."
While parents in the US would still be able to choose to vaccinate their children, health experts argue that requiring separate shots and additional clinic visits could lead some families to delay or skip vaccinations altogether. The changes could also reinforce existing vaccine hesitancy, leaving populations more vulnerable to outbreaks of diseases that have been eliminated or brought under control in many countries.
Europe has already felt the consequences of slipping coverage. According to the WHO, six countries—Armenia, Austria, Azerbaijan, Spain, the United Kingdom and Uzbekistan—re-established measles transmission in 2024. Measles is a highly contagious virus that can cause severe complications, and its return is often the first sign of immunisation gaps.
"We are already now seeing the return of measles whenever the vaccination coverage gets lower," Cavaleri said. "And we will see more coming, unfortunately, in the United States and other parts of the world." He warned that the situation could become "much worse" if vaccination numbers fall further, pointing to the threat of polio. "Just think about poliomyelitis. Do we want this to come back? I hope not," he urged.
The European Commission’s State of Vaccine Confidence report shows that overall trust in vaccines has declined among the general public since 2020, with particularly notable drops in several Central and Eastern European countries. The US decision could accelerate that trend, undermining the fragile gains made in recent years.
Infectious diseases do not respect borders. As Cavaleri put it, "Europe is the region that we have a duty to look at. But these infectious diseases are causing global problems, global outbreaks, global epidemics." The WHO’s Tedros echoed that sentiment, saying that "recent changes to US immunisation policy are not aligned with decades of evidence."
For European policymakers, the message is clear: maintaining high vaccination coverage is not just a domestic priority but a continental one. The US experiment with vaccine policy could become a cautionary tale—or a blueprint for a more dangerous future.
