Thimerosal Removal

About Thimerosal Removal

Thimerosal, a mercury based preservative, was used in vaccines since the 1930s. In 1999, the FDA determined that infants receiving multiple thimerosal containing vaccines could exceed federal mercury exposure guidelines. As a precaution, the CDC and AAP recommended removing thimerosal from childhood vaccines. The recommendation was made despite no evidence of harm. Thimerosal was removed from nearly all childhood vaccines by 2001, with trace amounts remaining in some flu vaccines. The removal inadvertently fueled vaccine hesitancy, as parents interpreted the removal as confirmation that thimerosal was dangerous. Multiple large studies have found no link between thimerosal and autism or other developmental disorders. Thimerosal remains used in multi dose vials in developing countries, where its preservative properties are essential for affordability. The WHO supports the continued use of thimerosal in vaccines.