WASHINGTON, March 17 (UPI) -- New calculations suggest children today can be exposed to more than half the mercury that was in vaccines in the 1990s, even though manufacturers began phasing it out in 1999.
Adjusted for a child's body weight at the time of the shots, there's virtually no reduction at all, according to this analysis.
The source: Flu vaccines, which have been recommended for millions more kids over 6 months old and pregnant women in the past few years. Most of those shots still contain the mercury-based preservative called thimerosal that some fear is behind a huge rise in autism diagnoses.
"It's been under the radar and it's allowed health officials to say, 'We've taken it out of all the childhood vaccines,'" said Dr. David Ayoub, an Illinois anti-thimerosal activist who put the data together along with Maryland researchers David Geier and Dr. Mark Geier.
"They don't consider influenza one of the mandated childhood vaccines yet," Ayoub said. But because the Centers for Disease Control and Prevention now recommends flu shots for all pregnant women and all children between 6 months and age 5, doctors routinely give them.
The CDC and the American Academy of Pediatrics urged in 1999 that manufacturers remove thimerosal from childhood vaccines amid concerns over mercury exposure from shots including hepatitis B and the diphtheria-pertussis-tetanus combination shot.
"Because any potential risk is of concern, the Public Health Service, the American Academy of Pediatrics, and vaccine manufacturers agree that thimerosal-containing vaccines should be removed as soon as possible," they said in a joint statement at the time.
Since then, however, the CDC has significantly broadened its flu-shot recommendations. And the "coverage" rate -- the percent of those who actually get the recommended shots -- is rising as well.
The thrust of the numbers compiled by Ayoub and the Geiers: By 5, children exposed to an all-thimerosal schedule of flu shots would get 53 percent of the mercury the same kids got from all shots in 1999, they concluded.
Ayoub then calculated cumulative weight-adjusted mercury exposures at less than 5 years of age. That shows kids getting 36.34 micrograms of mercury per kilogram of body weight in 1999 -- and 33.2 from the influenza vaccine recommendations in 2006, or only about 10 percent less.
Of course, a lot has happened since 1999. Chiefly, the independent, prestigious Institute of Medicine ruled out thimerosal, and vaccines in general, as a cause of autism and said it wasn't worth the research money to keep exploring.
On the other hand, a University of Washington researcher showed twice as much ethyl mercury that comes from thimerosal gets trapped in the brain as does methyl mercury that comes from fish and pollution, and it stays there indefinitely. And the CDC study most often invoked to show that thimerosal isn't linked to autism was later pronounced a "neutral study" by its principal author, meaning more research is needed.
Plus, the autism rate has started to drop in California since thimerosal was removed. Finally, as we've pointed out, the CDC continues to research whether thimerosal causes autism -- that hasn't been "ruled out," nor has any other cause, a spokesman told us earlier this year.