Taking Mercury Out of the Mix

Parents have become increasingly worried about the use of mercury as a preservative in children’s vaccines. After all, the heavy metal can impede brain development, and children receive almost two-dozen vaccine doses by the time they begin kindergarten.

Now comes a reformulated vaccine that may ease, if slightly, some parental fears.

The Food and Drug Administration last week approved a new version of the vaccine for diphtheria, pertussis (whooping cough) and tetanus that contains only 0.5 micrograms of mercury, a 95% reduction.

Although federal officials have been careful to say that no one has linked the mercury-containing preservative (thimerosal) to children’s health problems, the Public Health Service, the American Academy of Pediatrics and vaccine manufacturers have agreed it should be reduced or taken altogether out of vaccines.

Since 1999, the FDA also has approved pediatric formulations of hepatitis B vaccines that contain either no thimerosal or trace amounts.