evidence: Many rigorous studies show that there is no link between MMR vaccine or thimerosal and autism. Although many parents are aware of this research, some parents have lingering questions and concerns. I've heard some parents say their child's behavior changed after vaccines; how do you know vaccines don't cause autism? [...] - Give patient and empathetic reassurance that you understand their infant's health is their top priority, and it also is your top priority, so putting children at risk of vaccine-preventable diseases without scientific evidence of a link between vaccines and autism is a risk you are not willing to take.