Seth Mnookin's forthcoming book is The Panic Virus: A True Story of Medicine, Science, and Fear.
From his Q & A at Publishers Weekly:
Can we just dismiss all the reports of mercury-containing vaccines causing autism?--Marshal Zeringue
News reports present an "on the one hand-–on the other hand" debate. In actuality, you have thousands of pieces of data on one side and, literally, no verifiable data on the other. Scientists have not identified any risk of developmental disorders; accounts of vaccines leading to autism are entirely anecdotal. Scientists don't rely on anecdotes because memory is fallible, and in retrospect things often seem to fit together more neatly than they did in the moment. Children have been diagnosed with autism after being vaccinated, but that's because almost all children get vaccinations before age two, and autism is usually diagnosed after age two.
What about the research published by Dr. Andrew Wakefield in the Lancet linking the measles/mumps/rubella vaccine with autism?
That paper was proven false. The Lancet retracted it and 10 coauthors disavowed it. Wakefield's lab received payments through a law firm that was suing vaccine makers; some of the families of children studied in the paper were involved in those lawsuits. Wakefield's data were never independently verified, but even if they had been accurate, the small sample size—12 children—means any correlation found between vaccines and autism is likely to have happened by chance.
So why doesn't the controversy die down?