Today, the FDA approved a newly formulated version of Tripedia, a diphtheria and tetanus toxoids and acellular pertussis (DtaP) vaccine without preservatives and with only a trace amount of thimerosal.

"This approval is significant because now all routinely recommended pediatric vaccines will be available as either completely thimerosal free or without any significant amounts of thimerosal, a preservative that contains mercury," said Dr. Bernard Schwetz, Acting Principal Deputy Commissioner. "Although thimerosal is a very effective preservative, the Public Health Service recommended that thimerosal should be reduced or eliminated from vaccines as soon as possible to minimize the exposure of infants and young children to mercury."

Tripedia now contains less than 0.5 micrograms of mercury per dose, a greater than 95% reduction in the amount of thimerosal per dose compared to the original version of Tripedia.

The pediatric vaccines that are recommended for routine use are: DTaP, hepatitis B, Haemophilus conjugate (Hib), pneumococcal conjugate, inactivated poliovirus, varicella, measles, mumps and rubella. Since 1999, pediatric formulations of hepatitis B vaccines that either contain no thimerosal (Recombivax HB) or trace amounts (EngerixB) have been approved.

In recent years, various federal agencies have been addressing the health risks of mercury, which is found in the environment, in food and in household products.  Although no harmful effects have been reported from thimerosal at doses that were used in vaccines, the PHS agencies, the American Academy of Pediatrics, and vaccine manufacturers agreed that thimerosal should be reduced or eliminated in vaccines to make already safe vaccines even safer.

Further information about thimerosal is available at
http://www.cdc.gov/nip.vacsafe/concerns/thimerosal/thimerosal.htm.