Researchers from the [California] State Public Health Department found that the

autism rate in children rose continuously in the study period from 1995

to 2007. The preservative, thimerosal, has not been used in childhood

vaccines since 2001, except for some flu shots. Doctors

said that the latest study added to the evidence against a link between

thimerosal exposure and the risk of autism and that it should reassure

parents that vaccinations do not cause autism. If there was a risk, the doctors said, autism rates should have dropped from 2004 to 2007.