WHO chief warns US vaccine policy ignores science

The head of the World Health Organization has voiced concern over a recent executive order in the United States that seeks to overhaul the country's childhood vaccination schedule, arguing that the move is not supported by scientific evidence.

Speaking at a press conference in Geneva on Wednesday, WHO Director-General Tedros Adhanom Ghebreyesus said the policy change announced by the US government earlier this week is "not aligned with the best science." He stressed that decades of evidence have established the safety and effectiveness of vaccines, including the measles, mumps and rubella (MMR) vaccine, and that there is no link between vaccines and autism.

"Delaying vaccines or separating doses unnecessarily does not make vaccination safer, and can leave children unprotected," Tedros said. He added that vaccination policy should be based on rigorous, independent and transparent review of scientific data, not political influence.

The executive order, signed by US President Donald Trump on Monday, calls for a revised vaccine schedule that promotes spacing out childhood shots into separate medical visits. It also directs the health department to develop a plan to offer separate single-disease vaccines for measles, mumps and rubella, a combination shot that is currently standard practice.

Public health experts have warned that spreading out vaccinations increases the window in which children could contract preventable diseases. Studies have shown that combination vaccines improve the likelihood that children complete their full immunisation schedule by age two.

The order comes amid a measles outbreak in the US and as kindergarten vaccination rates have declined, with exemption rates reaching an all-time high in the 2024-25 school year. The American Academy of Pediatrics said the announcement spreads unwarranted uncertainty and fear among parents.