[JURIST] The US Court of Appeals for the Federal Circuit [official website] on Friday affirmed [opinion, PDF] a decision issued last year by the US Court of Federal Claims [official website] finding insufficient evidence [JURIST report] to establish a link between childhood vaccines and autism in three test cases. The decision focused on the case of 15-year-old Michelle Cedillo, who received the MMR vaccine [NIH backgrounder] when she was 15 months old and was subsequently diagnosed with autism and various gastrointestinal disorders. Michelle’s parents alleged that Thimerosal [FDA backgrounder], the mercury-based preservative found in Michelle’s MMR vaccine, damaged her immune system, rendering her unable to defend against the measles virus contained in the vaccine, which spread throughout her body and caused her current problems. The family sought compensation under the no-fault National Vaccine Injury Compensation Program [HRSA backgrounder]. The court found petitioners were unable to establish that the MMR vaccine was a substantial factor in bringing about Michelle’s injuries and that the lower court did not err in placing this burden on petitioners. The court also affirmed the lower court’s finding that the Department of Health and Human Services (HHS) [official website] experts proved petitioners’ laboratory results establishing the connection between the vaccines and illnesses were “severely flawed.” The court also found petitioners’ argument that the lower court failed to consider pertinent testimony to be “unpersuasive.”

In March, the US Federal Court of Claims determined that Thimerosal did not cause childhood autism [JURIST report] in three compensation actions. The special master found that the petitioners failed to present “a scientifically sound theory” and cited evidence that was “biologically implausible.” Thimerosal has also been involved in other health-related debates. In 2005, HHS officials argued that state laws prohibiting the chemical could impede efforts [JURIST report] to fight an avian flu pandemic in the event of an outbreak. Most doctors believe Thimerosal is safe and does not affect the body in the same manner as mercury found in pollutants, but activist groups disagree claiming use of the preservative can be linked to neurological diseases including autism. Officials argue that mercury-free vaccines can only be packaged in individual doses, which could pose a major problem in the event of a pandemic requiring production of large doses of vaccinations.