It's going to happen. I believe that vaccines don't cause autism but they do make it worse, because autistic people have low levels of S-adenosyl methionine (SAM). SAM is used for many things but one of them is converting toxic heavy metals like mercury into a form that can be eliminated from the body. Thus, in theory autistic people could suffer noticeable effects from the thiomersal in vaccines that would be safe for normal people. Remember, the body is often really good at coping with the effects of many chemical stressors, right up until it isn't; that is, while there are sufficient reserves to deal with the problem, there's little or no sign that anything is even wrong but then the reserves run out and you have a sudden crisis with no sign of what caused it.
People are going to take this vaccine en masse and there will be a ton of people whose autism suddenly gets worse when it previously wasn't noticed and we'll have a new wave of anti-vaxxers and vaccine skeptics. Frankly, the modern medical establishment has become so incompetent, authoritarian and captured by Big Pharma that it needs to be brought down a few notches in the public opinion.