What Parents Should Know About the Use of Thimerosal in Vaccinations

Vaccinations are recommended for all children, beginning at birth. There has been a great deal of controversy over the safety of vaccinations. Over the years, concern about a possible relationship between autism and thimerosal has motivated much research on the subject. Thimerosal is an organic mercury-based preservative that was used in small amount in many vaccinations. Currently almost all immunizations that are given to children under the age of two are thimerosal-free or contain extremely small amounts of thimerosal.

Thimerosal is used as an addiditve to vaccines because it is effective in preventing bacterial and fungal contamination. It has been used since the 1930's and is also found in other medicines and products available to consumers. You can find thimerosal in many throat sprays, nose sprays and contact lens solutions.

There are no valid studies that show a link between thimerosal in vaccines and autism. The Center for Disease Control has examined the incidence of autism in relation to the use of thimerosal a child has received in vaccinations. Children who received more thimerosal were not any more likely to develop autism than their peers that may not have received as much thimerosal. However, an early CDC study did suggest a possible connection between the amount of thimerosal and some types of neurodevelopmental disorders. ADHD, speech and language delays and tics fall into this category. Upon further review of the initial study, experts found less and less reason to believe the two were connected.

Since 2001, all recommended vaccinations used in infants and children under the age of two have been thimerosal-free or have very small amounts of the additive. In 2004, the American Academy of Pediatrics recommended that children 6-23 months of age receive an annual flu shot. There are thimerosal-free vaccinations available for the flu. Many recommended childhood vaccinations have never contained thimerosal. MMR, polio and the chicken pox have never had the additive in the vaccination. Some of the Hib and DTaP vaccines also never used thmerosal as a preservative.