Information about Thimerosal
Thimerosal is a mercury-based preservative that has been used for decades in the United States. It is added to vials of vaccine that contain more than one dose to stop bacteria and fungi from growing. This contamination may occur when a syringe needle enters a vial as a vaccine is being prepared for administration, and could cause severe local reactions, serious illness, or death. In some vaccines, preservatives are added during the manufacturing process to prevent microbial growth.
Thimerosal has a proven track record of being very safe. It does not stay in the body a long time so it does not build up and reach harmful levels. When thimerosal enters the body it breaks down to ethylmercury and thiosalicylate, which are easily eliminated.
Data from many studies show no convincing evidence of harm caused by the low doses of thimerosal in vaccines. The most common side-effects are minor reactions like redness and swelling at the injection site.
More information about Thimerosal and Ethylmercury.