I believe mercury exposure may drive a certain amount of the diagnosed cases of autism, but the many studies done DON'T support it being from vaccines. And given that it's a spectrum disorder, it almost certainly doesn't have a unitary cause. So you could be going after careers in engineering, given that engineers have more autistic children than non-engineers.
Also, Big Tobacco trotted out a few scientists who sold themselves, but the vast scientific consensus leans against vaccines causing autism.