[JURIST] The US Court of Federal Claims [official website] on Thursday rejected arguments made in three test cases against the US Department of Health and Human Services (HHS) [official website; HHS statement] by families alleging that their children's autism was caused by a combination of common childhood vaccines. Due to the case volume and complexity of the so-called Omnibus Autism Proceeding [court backgrounder, PDF; HRSA backgrounder], the court ordered separate trials based on three distinct theories of liability under the National Vaccine Injury Compensation Program [HRSA backgrounder], and in 2007 court-appointed special masters began hearing three test cases for each theory. Thursday's judgments roundly rejected the first theory of liability, that the Measles, Mumps, and Rubella combination vaccine (MMR) [CDC backgrounder] vaccines and thimerosal-containing vaccines [FDA backgrounder] can combine to cause autism. In Cedillo v. Secretary of Health and Human Services [opinion, PDF], a special master held that the evidence presented was "overwhelmingly contrary to the petitioners’ contentions" and that the Cedillo family failed to demonstrate that the vaccinations at issue played any role in the child's autism. In Hazlehurst v. Secretary of Health and Human Services [opinion, PDF], the special master held that the combination of the thimerosal-containing vaccines and the MMR vaccine are not causal factors in the development of autism, and could not have contributed to the development of autism. In Snyder v. Secretary of Health and Human Services [opinion, PDF], a third special master held that the Vowell family failed to show by a preponderance of evidence that their child's autism was caused or significantly aggravated by a vaccine, adding that it was "abundantly clear that petitioners’ theories of causation were speculative and unpersuasive." All plaintiffs have indicated that they will appeal the decisions. Special masters will continue to hear three cases on a second theory of liability – that thimerosal-containing vaccines alone can cause autism – with judgments expected this summer. Cases testing the final theory of HHS liability – that MMR vaccines alone can cause autism – have been dropped.

Thimerosal, a mercury-based preservative, has been at the center of several health debates. In 2005, HHS officials said that state laws prohibiting thimerosal could impede efforts [JURIST report] to fight an avian flu pandemic should an outbreak occur. Most doctors believe thimerosal is safe, saying it does not affect the body in the same manner as mercury found in pollutants, but several groups claim that use of the preservative can be linked to neurological diseases including autism. Creation of mercury-free vaccines requires packaging individual doses, which is expected to pose a major problem if large batches of the vaccine need to be rushed in the event of an avian flu pandemic. Doctors partially attribute recent outbreaks of measles and other infectious diseases [Bloomberg report] in the US to an increasing reluctance among parents to expose children to vaccines.