Researchers in the Department of Pediatrics at the University of California studied the incidence of autism in California from 2001 to 2007. They started the study in 2001 because increasing concerns about ethylmercury led to the removal of thimerosal from vaccines between 1999 and 2001.
The researchers wanted to determine if the removal of thimerosal led to a decrease in autism. California has a very accurate autism registry as part of the California Department of Developmental Services. They found that the incidence of autism increased quarter by quarter throughout the study period.
The scientists concluded that since autism increased despite the removal of thimerosal, it follows that vaccines containing thimerosal are not a primary cause of autism.”