Deep Dive: Vaccines don’t cause autism. Here’s how scientists figured that out

In the late 1990s, a theory gripped parents around the world: What if childhood vaccines — particularly the combined measles-mumps-rubella vaccine — cause autism? Nearly three decades later, the debunked theory has gained renewed prominence in parallel with the rise of Robert F. Kennedy Jr., a long-time anti-vaccine activist who now serves as the U.S. health secretary.

Scientists, medical providers and medical researchers are clear on this: Vaccines do not cause autism.