" After the antivaxxers’ claims that the MMR vaccine caused autism were debunked, they argued that the thimerosal in vaccines caused autism. After this was debunked, new claims surfaced that the cause was the vaccines being given too close together and too early, somehow shocking a child’s immune system and resulting in autism. This, too, was debunked. Science shows that even though the number of shots has risen over time, the actual load on the immune system has decreased because today’s vaccines are better engineered. Before 1991, the whooping-cough vaccine had three thousand different antigens. Today’s whooping-cough vaccine has no more than five particles—just as effective, but much easier on the immune system. After the “too many, too soon” myth was debunked, antivaxxers began claiming that the MMR vaccine was “triggering” autism in children who were somehow genetically predisposed to it. That, too, was debunked. "

― Shawn Lawrence Otto , The War on Science: Who's Waging It, Why It Matters, What We Can Do About It