The World Health Organization warned on Wednesday, Aug.12, that President Donald Trump’s plans to change childhood vaccination policies in the United States are not supported by decades of scientific evidence, as the country faces its worst measles outbreak in 35 years.
WHO Director General Tedros Adhanom Ghebreyesus said recent changes to U.S. vaccination policy could put children at greater risk by delaying vaccines or separating doses without a medical reason.
“Vaccines including the MMR vaccine are safe and do not cause autism,” Tedros said in a post on X. He urged governments to base vaccination policies on independent and transparent scientific research rather than political pressure.
Every parent wants to keep their children safe, and vaccines are among the most powerful tools for doing that, making deadly diseases preventable. @WHO is concerned that recent changes to US immunization policy are not aligned with decades of evidence that show when children… pic.twitter.com/vCfgJFrFGK
— Tedros Adhanom Ghebreyesus (@DrTedros) August 12, 2026
Trump signed an executive order Monday calling for a review of school vaccine requirements. He has also supported separating the measles, mumps and rubella vaccine into three individual shots.
The move has drawn criticism from health experts, particularly because Health Secretary Robert F. Kennedy Jr. has previously promoted claims linking vaccines to autism. Scientific research has found no evidence that vaccines cause autism.
Tedros said vaccination recommendations are based on extensive research showing which vaccines provide strong protection, how many doses are needed and which vaccines can safely be given together.
He added that health authorities regularly review the evidence as new information becomes available from around the world. The WHO chief also warned that delaying vaccinations or separating vaccine doses without a medical reason does not make immunization safer. Instead, he said, such steps can leave children without protection against serious diseases.
The warning comes as the United States faces a major measles outbreak. The country is experiencing its worst measles outbreak in decades, with children preparing to return to school. Health officials have expressed concern that infections could spread further as students return to classrooms.
Kennedy has also ordered a broad review of vaccines, including several that have been used for many years. His changes to the childhood vaccination schedule and cuts to vaccine development funding have faced strong criticism from medical and scientific groups.
Tedros urged parents to continue viewing vaccines as an important tool for protecting children from serious diseases. He said vaccines help prevent illnesses that can otherwise become deadly.
