Even as the new H1N1 vaccine has revived fears about vaccine safety, one more study was released last week showing that use of the mercury-based preservative thimerosal in shots does not translate into elevated mercury levels in children’s blood.
Amid heated debate over whether or not thimerosal – used to prevent cross-contamination in vaccines packaged in multi-dose vials – is linked with autism, its use in childhood vaccines was reduced or eliminated in the U.S. in 2001. But it is still used in some forms of seasonal flu vaccine, including the new vaccine against H1N1. The pandemic flu has proven especially dangerous to children, who are on the priority list to receive the vaccine.
In their study, supported by the National Institutes of Health and reported in the Journal of Pediatrics, researchers from the Rochester General Health System in New York found that the blood levels of mercury in even premature and low-birthweight infants were exceedingly low after vaccination. They tested the blood of 72 newborn infants in Argentina (where vaccines are purchased through the World Health Organization, which has categorically rejected the notion that thimerosal is unsafe) both before and after vaccination. Their blood levels of mercury rose very slightly, and then returned to pre-vaccination levels within 10 days.
Previous studies by the same researchers involving full-term newborns and 2- and 6-month-old babies showed similar results. Even so, parents who want their children to receive thimerosal-free flu shots can choose the inhaled version of the vaccine, or shots packaged in single-dose vials, neither of which contain the preservative.
One Friday night during the second semester of his freshman year at college, John Kach didn’t feel good. “I started to vomit,” says Kach, who is now 28. “That was the first thing that happened.” He developed a fever, decided he had the flu, and told his girlfriend he’d feel better in the morning.
