Before the Committee on Government Reform
U. S. House of Representatives
April 26, 2001

http://www.cdc.gov/washington/legislative/04262001.htm

Despite the fact that thimerosal preservative has been effective in lowering the risk that vaccines could be contaminated by bacteria leading to serious infection, the United States Public Health Service agencies, including NIH, FDA, HRSA, and CDC, working collaboratively with the American Academy of Pediatrics and the American Academy of Family Physicians, took action in mid-1999 to begin removing thimerosal preservative from the vaccine supply. While the risk of harm from this source was only theoretical, the decision was made as a precautionary measure. The elimination of thimerosal preservative from vaccines was judged a feasible means of reducing an infant’s total exposure to mercury in a world where other environmental sources of exposure may be more difficult or impossible to eliminate.

 As a result of this action, all manufacturers of routinely recommended licensed pediatric vaccines are now producing for the U.S. market only vaccines that are thimerosal-free or contain trace amounts of thimerosal. The vaccines are supplied in single-dose vials which eliminates the need for a preservative.

http://www.cdc.gov/washington/legislative/07182000.htm

The United States has been a world leader in the development and licensing of new vaccines and has placed a high priority on producing vaccines which meet the highest standards for safety and efficacy. These standards pertain not only to the active ingredients, which elicit protective immune responses, but also to the preservatives such as thimerosal. Thimerosal, an ethylmercury containing preservative used since the 1930's, is added to some vaccines because it is very effective in preventing bacterial contamination and resulting infections in vaccine recipients.

In mid-1999 administration of a combination of vaccines that contained thimerosal as a preservative was recognized as exceeding one federal guideline for mercury exposure. It is important to note that the form of mercury used in thimerosal is ethylmercury. Although toxicity data are lacking for ethylmercury, it is currently assumed that methylmercury guidelines are appropriate to use in this situation. Even though there was no evidence of possible harm caused by ethylmercury exposure from immunizations, the United States Public Health Service agencies, including NIH, FDA, HRSA, and CDC took action, working collaboratively with the American Academy of Pediatrics and the American Academy of Family Physicians. Last summer a goal was set for the removal or significant reduction of thimerosal as a preservative from all vaccines routinely administered to children in the first year of life. While the risk of harm from this source was only theoretical, the decision to set a goal to remove thimerosal was made as a precautionary measure. Given the concern about the health effects of mercury of any sort, the elimination of mercury from vaccines was judged a feasible means of reducing an infant's total exposure to mercury in a world where other environmental sources of exposure may be more difficult or impossible to eliminate.

During the year since the goal was set, progress in removing or reducing thimerosal in vaccines has been outstanding. The United States has now achieved a pediatric hepatitis B vaccine supply from two manufacturers that is free of thimerosal as a preservative, and, as of this month, a Haemophilus influenzae type b vaccine supply from all four manufacturers is available that is free of thimerosal as a preservative. For DTaP vaccines, there are four manufacturers, one of which has produced a vaccine that is already free of thimerosal, and at least one other is expected to produce a vaccine without thimerosal as a preservative within six to nine months. Measles, mumps, rubella, varicella, inactivated polio, and the recently licensed conjugate pneumococcal vaccines have never contained thimerosal. Based on our progress over the past year, the maximum amount of mercury an infant may be exposed to from routine immunizations has been reduced by 60 percent.

Thus, by early 2001, the United States is expected to have obtained an adequate vaccine supply for the routine pediatric vaccines that is completely free of thimerosal as a preservative.