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.

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

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.