SUMMARY: CONTRARY TO VACCINE OPPONENT OPINIONS, THERE IS NO CONVINCING EVIDENCE THAT EARLY EXPOSURE TO THIMEROSAL HAD ANY RISK TO AUTISM OR AUTISTIC SPECTRUM DISORDERS.

Thiomerosal is a preservative that is used in low doses of vaccines and contains 50% ETHYLMERCURY. Low doses of METHYLMERCURY consumed in certain populations that eat high amounts of fish and whale meat, can have developmental effects in young children. It has been suggested that ethylmercury can have a similar effect, though there is no evidence to support this claim. Moreover, ethylmercury is more quickly broken down and removed in the body. Based on the assumption that ethylmercury MIGHT have the same effect as methylmercury, the EPA lowered the maximum dose that infants should recieve. This was never a level that was thought to cause problems, and a 10 fold safety factor was built into this recommendation. As a result, anti-vaccine groups have seized that EPA guidelines as proof that children were recieving too much mercury and have further stated that the possible rise in autism is a direct result of this preservative. To remove this controversy, thimerosal was removed from all vaccines given to young children as of 2001.

Although thimerosal as a preservative is no longer present in recommended vaccines for children younger than 7 years in the United States, it is in vaccines worldwide. Many parents ask pediatricians this safety issue. Previous studies published in 2003, have shown that the MMR vaccine is NOT linked to autism. Anti-vaccine groups have continued to focus on thimerosal as a reason to not recieve vaccines. Two more studies published in the September 2004 issue of Pediatrics, have added to two other well done studies that show no link to autism and autistic spectrum disorders such as PDD.

CDC link to the association of MMR and autism
http://www.cdc.gov/od/science/iso/mmr_autism.htm