The CDC changed its autism–vaccine webpage, creating debate among doctors, experts and lawmakers. The update uses new language about vaccines and autism, and this has raised concern from many medical groups.

Kennedy told The New York Times he personally ordered the language change. There’s no evidence to support the claim. Dr. Demetre Daskalakis, the former head of the National Center for Immunization and Respiratory Diseases, who resigned from the role earlier this year, called Kennedy’s “update” a national embarrassment.

Public health experts warn that a major communication failure could worsen mistrust of vaccines, a problem brought to light by the CDC’s sudden revision of its long-standing autism and vaccines webpage.

Alongside the guidance update, HHS plans to study biological mechanisms and possible links that may contribute to autism.