What childhood vaccines contain thiomersal?
Thiomersal is a compound used in small amounts to prevent bacterial and fungal contamination of vaccines. Thiomersal is partly composed of mercury in the form of ethylmercury. Mercury causes a toxic effect after it reaches a certain level in the body. Whether or not it reaches a toxic level depends on the amount of mercury consumed and the person’s body weight. As a result of these concerns, in particular for newborn babies and very young children, thiomersal was removed or reduced from vaccines. Currently, all vaccines on the National Immunisation Program for children under 5 years of age are now either thiomersal free or have only trace amounts of thiomersal. It is not possible to completely remove thiomersal from all vaccines, some vaccines like Energix-B are still most effectively manufactured using a trace amount of thiomersal as a preservative.
