Public release date: 30-Jan-2008

(An Extremely Flawed Study)

February’s issue of Pediatrics offers another reason to rethink blaming the spike in autism diagnoses on thimerosal, a mercury-containing preservative routinely used in several childhood vaccines until the late ‘90s.

New research from the University of Rochester suggests that infants’ bodies expel the thimerosal mercury much faster than originally thought – thereby leaving little chance for a progressive building up of the toxic metal. This debunks the great myth, believed by both parents and some pediatricians, that the gauntlet of thimerosal-containing shots many infants received in the 1990s – when the average number of vaccines kids received increased sharply – had put them at risk for developmental disorders.

“Thimerosal has been used for decades, but the surge in vaccinations caused fear that possible accumulations of ethyl mercury, the kind in thimerosal, might exceed safe levels – at least, when based on the stringent risk guidelines applied to its better-understood chemical cousin, methyl mercury, which is associated with eating fish,” said Michael Pichichero, M.D., professor of Microbiology/Immunology, Pediatrics and Medicine at the University of Rochester and the study’s main author.

But scientists are learning that the two mercury species actually behave quite differently; in fact, the body rids the kind found in thimerosal more that 10 times faster than it removes the kind one might encounter in a Friday night fish fry.

In the Rochester study, 216 infants from R. Gutierrez Children’s Hospital (in Buenos Aires, Argentina, where thimerosal is still routinely used in vaccines) were divided into three age groups to have their blood-mercury levels tested both before and after shots were administered at either their newborn, 2- or 6-month checkup. Researchers learned that, in all three age groups, the half-life of ethyl mercury in the blood – or, the time it takes for the body to dispose of half the mercury, and then another half, and so on – was measured to be 3.7 days. That’s a far cry from the blood half-life of methyl mercury, which is 44 days.

“Until recently, that longer half-life was assumed to be the rule for both types of mercury. Now it’s obvious that ethyl mercury’s short half-life prevents toxic build-up from occurring. It’s just gone too fast,” Pichichero said.

“Though it’s reassuring to affirm that these immunizations have always been safe, our findings really have greater implications for world health,” Pichichero said. “Replacing the thimerosal in vaccines globally would put these vaccines beyond what the world community could afford for its children. It’s a relief we haven’t cause to do that.”

Ralph’s Note – Hmmm. Here all this time, I thought mercury migrated to the soft tissues and bone in the body not the blood. Maybe this doctor should take some thimersol himself and test it’s excretion rate over time. After all if its safe to give to infants. I am sure he won’t mind proving Thimersols safety to us personally.