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

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

Dozens of studies have failed to find evidence of a link. The decision to re-examine the question comes as a measles outbreak, driven by low vaccination rates, widens in Texas.