New results about toxicity of thimerosal
Thimerosal, an organomercury compound which has been used since the 1930's as a preservative in vaccines is much faster cleared from the body than methylmercury, mainly taken up from contaminated fish. This is the result of a study recently published by a group of US researchers in Environmental Health Perspectives.
The group compared the systemic disposition and brain distribution
of total and inorganic mercury in infant monkeys following thimerosal
exposure with infants exposed to MeHg. The initial and terminal
half-life of Hg in blood following thimerosal exposure was 2.1 and 8.6
days, which are significantly shorter than the elimination half-life of
Hg following methylmercury exposure at 21.5 days. Brain
concentrations of total mercury were significantly lower by ~3-fold for
the thimerosal-exposed infants when compared to the
methylmercury infants and a higher percentage of the total
mercury in the brain was in the form of (less toxic) inorganic
mercury for the thimerosal-exposed infants (34% vs 7%).
This study indicates that methylmercury is not a suitable
reference for risk assessment from exposure to thimerosal derived
mercury. Toxicokinetics and developmental toxicity of thimerosal itself
have to be studied to afford a meaningful assessment of the effects of
Until such data is available, the current debate linking the use
of thimerosal in vaccines to autism and other developmental disorders
(IOM 2001, 2004) will probably continue (see news below).
Thomas M. Burbacher, Danny D. Shen, Noelle Liberato, Kimberly S. Grant, Elsa Cernichiari, and Thomas Clarkson, Comparison of Blood and Brain Mercury Levels in Infant Monkeys Exposed to Methylmercury or Vaccines Containing Thimerosal
, Environmental Health Perspectives, April 2005
Science Daily, May 17 2005: The Age of Autism: Mercury ascending
Environmental Science & Technology, A-pages, June 1, 2005, 234A, The brain is defenseless against mercury
American Council on Science and Health, August 26, 2005: Autistic Boy Dies After Chelation Therapy News from The Sierra Times, September 3, 2005: David Ayoub MD - Thimerosal Definite Cause of Autism Free Market News Network, March 2, 2006: Non-Mercury vaccines cut autism
Kearney hub, March 7, 2006: Differing view on mercury in vaccines Milford Daily News, March 7, 2006: Report: Government knew of autism link EVISA News, March 24, 2006: American lawmakers initiate mercury probe for vaccines The Huffington Post, November 15,2006: The Other Secret Bush Court?
last time modified: November 20, 2006