children s health issues
Childhood Vaccination Concerns
Thimerosal: Concerns about Autism
People have also been concerned about possible side effects of thimerosal. Thimerosal was previously used as a preservative in vials that contain more than one dose of a vaccine (multidose vials). Preservatives are not needed in vials that contain only one dose (single-dose vials), and they cannot be used in live-virus vaccines (such as rubella and varicella). Thimerosal, which contains mercury, is broken down by the body intoethylmercury, which is eliminated quickly from the body. Becausemethylmercury (which is a different compound that is not eliminated from the body quickly) is toxic to humans, there was concern that the very small amounts of thimerosal used in vaccines might cause neurologic problems, particularly autism, in children. The World Health Organization (WHO) has not recommended thimerosal be removed from any vaccines because there is no evidence that routine use causes any harm. However, because of theoretical concerns and even though no studies had shown evidence of harm, thimerosal was removed from routine childhood vaccines in the United States, Europe, and several other countries by 2001. In these countries, small amounts of thimerosal continue to be used in certain influenza vaccines, as well as in several vaccines intended for use in adults. Yearly flu vaccines are recommended for all children, and parents who are worried about thimerosal can ask for a flu vaccine that does not contain thimerosal. (See alsoCDC: Thimerosal FAQs). The removal of thimerosal from routine childhood vaccines has had no effect on the number of children who have developed autism. 