Croatian immunologist Zlatko Trobonjača and American pediatricians sharply condemn the decision that reduces the number of recommended vaccines and splits the MMR, warning of chaos and the return of nearly eradicated diseases.
U.S. President Donald Trump signed an executive order on Monday, August 10, 2026, that drastically changes the country's childhood vaccination program, sparking an outcry among medical experts worldwide. The order limits the number of recommended vaccines to just 11 and requires the combined MMR vaccine against measles, mumps, and rubella to be split into three separate doses.
The decision comes at a time when the U.S. is experiencing its largest measles outbreak in more than 30 years, and vaccination rates are falling. In the 2024/25 school year, the share of children with vaccination exemptions reached its highest level ever.
Dr. Molly O'Shea, a pediatrician from Michigan, noted that families are currently preparing their children for the return to school. "Questioning the safety or effectiveness of these vaccines right now is truly reckless and wrong," she said. She added that the claim that splitting the MMR vaccine has value is "inaccurate both in science and in the immune response."
Dr. Paul Offit, a vaccine researcher at Children's Hospital of Philadelphia and a former government adviser, was even more direct: "The harm this will cause is... creating chaos and confusion in the system, so that people are not sure what they should do."
During the signing of the order in the Oval Office in Washington, Trump claimed that the MMR vaccine could be "quite deadly" when given together, but that individually it is "not deadly at all, but just very effective." Doctors dismissed this characterization, emphasizing that the combined vaccine has undergone rigorous trials and years of safety monitoring that have shown it to be extremely safe.
Even Republican Senator Bill Cassidy of Louisiana, a physician and chairman of the Senate Health Committee, condemned the order. "I am a doctor. This executive order is wrong. The President does not have the expertise needed for such changes," Cassidy said. He also warned that splitting the vaccine would mean that "children will have to receive more shots to get the same protection."
Prof. Dr. Zlatko Trobonjača, a Croatian immunologist at the University of Rijeka, did not mince words when commenting on Trump's decision. "This decision by the American president is abnormal!" he said for Slobodna Dalmacija. "We have decades of experience with the MMR vaccine, and that experience has been without any consequences. These are serious diseases."
Trobonjača detailed the risks: mumps can affect the testicles and lead to infertility or cause inflammation of the pancreas, while measles in one in 1,000 cases ends in encephalitis, and in one in 10,000 cases can lead to subacute sclerosing panencephalitis, a virus invasion of the brain that can be fatal even after 15 to 20 years. Rubella, on the other hand, if it affects an unvaccinated pregnant woman, can cause severe fetal damage.
He was particularly concerned about limiting vaccination against hepatitis B. "At this moment, there are about 300 million people in the world who are carriers of the hepatitis B virus. They are infectious and transmit the disease through blood or sexual contact," he said. Chronic hepatitis B, he explained, can lead to liver cirrhosis or liver cancer 15 to 25 years after infection.
"And now, these Americans say 'we won't vaccinate children,' and I ask them, are they normal? This American government does not look like a serious government. To me, it looks like a 'freak show,'" Trobonjača said.
When asked why America is limiting vaccination, Trobonjača sees only one reason: "They are saving money; I see no other reasonable reason. We are talking about a country with 350 million inhabitants, and if you reduce 100 million vaccines a year, you save 300 million dollars, and for them, money is everything. They obviously don't care about public health."
The order comes after Health Secretary Robert F. Kennedy Jr., a longtime vaccine critic, had already in January dropped vaccines against six of the total 17 diseases from the U.S. vaccination program, but that decision was halted by a federal court. Trump's order now confirms Kennedy's changes despite the ongoing legal proceedings.
The American Academy of Pediatrics had already filed a lawsuit earlier this year over these changes. The Academy recommends vaccines against 18 diseases in 2026. Kennedy also dismissed the 17-member vaccine advisory committee. Michael Osterholm, an infectious disease expert at the University of Minnesota, said: "Parents deserve clear, evidence-based guidelines on how to protect their children, not conflicting recommendations made through political processes."
