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.

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.

Health and Human Services (HHS) officials led by Robert F. Kennedy Jr. recently confirmed that the Centers for Disease Control and Prevention (CDC) will investigate whether vaccines cause autism. The announcement reignited a longstanding debate over a theory lacking substantial scientific evidence.

Bill Cassidy said RFK Jr. pledged to keep communication lines wide open and to consult with the senator on vaccine policy.

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.

The US Centers for Disease Control and Prevention (CDC) is planning a large study into whether vaccines are linked to autism, despite this myth being robustly debunked by years of careful scientific research.