Prenatal and infant exposure to thimerosal, a mercury-containing
preservative used in some vaccines, does not increase risk for
autism spectrum disorder (ASD), according to a study published
in the October 2010 print issue of Pediatrics. In the study,
researchers tasked by the US Centers for Disease Control
reviewed health records and conducted interviews with the
parents of 256 children diagnosed with ASD. Children with ASD
were further categorized as having autistic disorder or ASD with
regression (meaning children with autism who lost previously
acquired language skills). Another 752 children without autism,
matched to the ASD children by birth year and gender, were also
studied. Researchers compared thimersol exposures during the
following time periods: prenatal, birth to 1 month, birth to 7
months, and birth to 20 months. Confirming previous vaccine
safety studies, researchers found no connection between
thimerosal exposure and increased risk for ASD in any of the
time periods. In an unexpected anomaly,