Thimerosal is an inorganic mercury compound that is metabolized to ethylmercury and thiosalicylate and has been present since the 1930’s as a preservative in some vaccines and pharmaceutical products to prevent bacterial and fungal contamination. First introduced by Eli Lilly Company, thimerosal is 49.6% mercury by weight and is metabolized or degraded into ethylmercury and thiosalicylate. Toxicity of mercury has been linked to many different diseases, including autism, learning disabilities, Alzheimer’s, multiple sclerosis, fibromyalgia, lupus, chronic fatigue syndrome, arthritis, depression, and bipolar disorder. Health effects of mercury toxicity have been a concern because of the potential for it to act as a poison.
In September 1999, the American Academy of Pediatrics issued a policy on mercury in vaccines that instructed that physicians should warn parents of risks associated with thimerosal and make available alternatives to thimerosal available, yet thimerosal vaccines continue to be used. Serious conditions such as autism, learning disabilities, Alzheimer’s disease, and other neurological conditions are associated with the exposure of thimerosal-containing vaccines.