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Hep B Vaccine With Thimerosal Linked to Developmental Delays in Animal Study

Oct 9, 2009 | Parker Waichman Alonso LLP

The vaccination debate has been a long and controversial one with claims of adverse effects as a result of the mercury-based preservative, thimerosal, at the root of the issue. Now, CBS News is writing that a new study conducted with rhesus macaque monkeys and thimerosal-containing hepatitis B vaccination points to some noteworthy physical delays.

The study indicates that those monkeys who were vaccinated demonstrated “significant delays in the acquisition of critical survival reflexes" versus the unvaccinated control group, said CBS News correspondent, Sharyl Attkisson. The study represents the first of its kind in which vaccinated and unvaccinated time controls were used, said CBS News, which explained13 newborn rhesus macaque monkeys received a vaccine with the hepatitis serum and that contain thimerosal in a dose equivalent to what was given to human babies up until the earlier part of this decade. Four baby monkeys received a saline placebo injection and three did not receive any shots.

Dr. Laura Hewitson of the University of Pittsburgh, a lead investigator in the study, said that baby monkeys who were not injected developed normally, while the monkeys who received vaccinations “demonstrated … survival reflex delays,” according to CBS. “Infants of lower birth weight and gestational age were at greater risk,” said Dr. Hewitson. The study was published last week in the scientific journal NeuroToxicology.

The study was not constructed to determine if thimerosal or any other element of the injection caused the delays, said CBS. “We undertook these experiments largely because we were unable to find any safety studies comparing vaccinated and unvaccinated animals,” said Dr. Andrew Wakefield of Thoughtful House, and another study author, quoted CBS. Thoughtful House, said CBS, offers resources for children diagnosed with developmental disorders.

In 1998, Wakefield and his team conducted research in Great Britain on a group of autistic children, said CBS. The results, which were published in the British Journal Lancet, opened a flood of controversy and called for additional studies to look at the safety of the three-in-one MMR—measles, mumps, rubella—vaccine, explained CBS. At the time, Wakefield suggested the vaccines be administered separately.

The earlier study actually began much of the arguments that went on between safety advocates and government and industry, with the U.S. Food and Drug Administration (FDA) and the American Academy of Pediatrics saying thimerosal is safe in vaccine doses, reported CBS. Although the toxin has been removed, for the most part, from vaccines, it is found in most flu shots, most notably in the recent H1N1 swine flu vaccines and is also present in other vaccines advertised as “preservative free.” To be thimerosal-free or –reduced, no preservative is permitted in the vaccine; however, trace amounts may be used during manufacturing and could be present in the final product, said CBS.

For years, many parents of autistic children argued that thimerosal used in vaccines had a connection to autism. No study was able to find a definitive connection, yet autism rates continued to rise despite the fact that the use of thimerosal was widely discontinued. According to the Boston Globe, the thimerosal theory became so highly controversial and polarizing within the autism community that for years, research into environmental triggers was looked upon with skepticism. But, as rates of autism reached epidemic numbers, scientists realized that genetic factors alone could not account for the upswing.