Infants Eliminate Mercury In Vaccines Faster Than Previously Thought - It Does Not Have Time To Build Up In Babies' Bodies

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Main Category: Autism
Also Included In: Pediatrics / Children's Health;  Immune System / Vaccines;  Public Health
Article Date: 03 Feb 2008 - 0:00 PDT

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Mercury, which can be used as a vaccine preservative is eliminated by infants faster than previously thought, according to a small study published in the journal Pediatrics. Many people have suspected that thimerosal, a mercury preservative pediatric vaccine ingredient which was used in the USA until the late 1990s, may have been an important contributory factor to rising autism rates in California. Several studies, including this one, seem to indicate thimerosal is not the link.

Lead author, Michael Pichichero, M.D., professor of Microbiology/Immunology, Pediatrics and Medicine, University of Rochester, said "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."

However, it seems that the human body eliminates the type of mercury that is included in vaccines (thimerosal) 10 times faster than the mercury that may be ingested as a result of eating fish.

The study, which was carried out at the R. Guitierrez Children's Hospital, Buenos Aires, Argentina, consisted of three groups.

-- Group One. 72 newborns.
-- Group Two. 72 babies aged two months.
-- Group Three. 72 babies aged 6 months.
(Thimerosal is still routinely used in vaccines in Argentina.)

The scientists gave each baby a thimerosal-containing vaccine. Most of the babies had their blood mercury, stool mercury and urine mercury levels tested prior to vaccination and then again after vaccination.

They found mercury in all the post-vaccination stool samples. They did not however, find any mercury in the post-vaccination urine tests. This indicated that the mercury was eliminated through the gut. A good sign as mercury at high levels is toxic to kidneys. No damage to renal tissues were found, the authors report.

The researchers found that the half-life of ethyl mercury in the blood was 3.7 days, compared to 44 days for mercury found in some foods.

Pichichero said "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."

The scientists found that the 6-month old babies, who had received more thimerosal than the babies in the other two groups, had the same blood-mercury levels as the pre-vaccination two-month old babies. This indicates that the mercury is eliminated between each bout of pediatric vaccines.

The authors wrote "Because of the differing pharmacokinetics of ethyl and methyl mercury, exposure guidelines based on oral methyl mercury in adults may not be accurate for risk assessments in children who receive thimerosal-containing vaccines."

Even though the California Department of Health removed thimerosal from the majority of US childhood vaccines in 2001, autism rates in the state continue to rise significantly, while thimerosal is still used in pediatric vaccines in many other parts of the world.

Thimerosal has bacteria-killing properties. It has been a vaccine ingredient for over seventy years. However, when the EPA (Environmental Protection Agency) announced in 1999 that the cumulative exposure children typically received in vaccines might exceed a safe level for intake based on methyl mercury statistics (even this "safe level" was placed ten times lower than the amount held to pose real risk), public health officials, along with the American Academy of Pediatrics, recommended it be removed - even though there was still no concrete evidence of harm. The decision demanded a new formulation be created and administered - at a higher cost.

Pichichero added "Though it's reassuring to affirm that these immunizations have always been safe, our findings really have greater implications for world health. 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."

Pichichero was a consultant to the World Health Organization, and his research has held considerable weight in the WHO decision to continue using thimerosal in vaccines administered in nations outside the United States. Pichichero had also been a consultant for GSK Biologicals, sanofi pasteur, Wyeth Pharmaceuticals and MedImmune - all vaccine manufacturers.

The National Institute of Allergy and Infectious Diseases of the National Institutes of Health (NIH) funded this study.

"Mercury Levels in Newborns and Infants After Receipt of Thimerosal-Containing Vaccines."
Michael E. Pichichero, MD, Angela Gentile, MD, Norberto Giglio, MD, Veronica Umido, MD, Thomas Clarkson, PhD, Elsa Cernichiari, MSc, Grazyna Zareba, PhD, Carlos Gotelli, PhD, Mariano Gotelli, PhD, Lihan Yan, MS and John Treanor, MD
Pediatrics Vol. 121 No. 2 February 2008, pp. e208-e214 (doi:10.1542/peds.2006-3363)
Click here to view abstract online

Written by - Christian Nordqvist
Copyright: Medical News Today
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