WHO reaffirms no link between vaccines and autism

The World Health Organization's vaccine safety committee said on Thursday that new reviews of scientific evidence found no link between vaccines and autism spectrum disorder, reaffirming conclusions reached more than two decades ago.

The WHO Global Advisory Committee on Vaccine Safety assessed two systematic reviews covering studies published between 2010 and August 2025.

The reviews examined vaccines in general and those containing thiomersal, a mercury-based preservative that has long been accused by critics of contributing to autism - a claim repeatedly dismissed by scientific studies.

A causal link between vaccines and health outcomes is considered only when several high-quality studies consistently show a statistical association, the committee said.

Twenty out of 31 studies found no evidence of an association between vaccines and autism, according to the WHO.

Eleven studies that suggested a possible link were deemed to have major methodological flaws and a high risk of bias, the committee said.

Last month, U.S. Health Secretary Robert F. Kennedy Jr. said in an interview with the New York Times that he had personally instructed the U.S. Centers for Disease Control and Prevention to change its long-standing position that vaccines do not cause autism.