It is unclear whether Health Secretary Robert F. Kennedy Jr, who has long promoted anti-vaccine views, is involved in the planned study or how it would be carried out.

The Centers for Disease Control and Prevention (CDC) will study whether vaccines cause autism, despite numerous existing studies already showing there is no link.

The US Department of Health and Human Services asked the US Centers for Disease Control and Prevention to study vaccines and autism, a person familiar with the situation told CNN, despite strong evidence that vaccines do not cause autism.