Doesn't have time to build to dangerous levels in body and cause autism, new research contends
WEDNESDAY, Jan. 30 (HealthDay News) -- The latest chapter in the debate over whether childhood vaccines can cause autism was written Wednesday with release of a study that showed the controversial mercury-containing preservative thimerosal is rapidly excreted from babies' bodies and can't build up to toxic levels.
"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," lead researcher Dr. Michael Pichichero, professor of microbiology/immunology, pediatrics and medicine at the University of Rochester, said in a prepared statement.
"One of the unanswered questions when this first popped up as a controversy was, when you got thimerosal as an injection, how long would it stay in your blood," co-author Dr. John Treanor, a professor of medicine at the University of Rochester Medical Center, said in an interview.
The new research, he added, showed that "the levels of thimerosal don't go very high and they go down right away. By the time it's time for the next dose of vaccine, the levels are right back to where they were at the beginning."
For their study, Pichichero's team tracked 216 infants from R. Gutierrez Children's Hospital in Buenos Aires, Argentina, where thimerosal is still routinely used in vaccines. Use of thimerosal in childhood vaccines was discontinued in the United States after a joint decision in 1999 by U.S. health officials, pediatricians and vaccine manufacturers.
The infants in the study were put into three age groups and their blood-mercury levels were tested both before and after vaccinations were given to
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