The U.S. Court of Federal Claims ruled last week in three bellwether cases that thimerosal vaccines do not cause autism in children. Three special masters of the Court ruled against plaintiffs in three separate test cases, finding insufficient evidence of a casual link between autism and the MMR (measles, mumps, rubella) vaccine.

Thimerosal has been widely used for decades as a preservative in a number of biologic and pharmaceutical products, including vaccines. It prevents life-threatening contamination. Increasing concern over the potential toxicity of the chemical has led to the removal or reduction to trace amounts of the preservative in most vaccines routinely given children aged 6 and under.

That same concern is behind numerous legal claims alleging that that routine childhood shots are to blame for the rising incidence of autism. The National Vaccine Injury Compensation Program, 42 U.S.C. §300aa-10, et seq., governs such claims, requiring plaintiffs to file a special no-fault compensation petition with the Court of Federal Claims, rather than a traditional suit against manufacturers. Part of the policy behind the program is the potential impact on public health of a traditional mass tort type of litigation involving life-saving vaccines, ranging from polio to chicken pox. Approximately 12,000 cases have been filed under the program.

To be eligible for compensation under the Vaccine Act, a petitioner must either demonstrate a “Vaccine Table” injury, to which a statutory presumption of causation attaches, or prove by a preponderance of the evidence that a vaccine listed caused or significantly aggravated an alleged injury. Althen v. Sec’y, HHS, 418 F.3d 1274, 1278 (Fed. Cir. 2005).  Autism claims fall in that latter category.  In 2002, the Court set up an Omnibus Autism Proceeding to test the three main theories of general causation: that the vaccines and thimerosal combine to cause autism; that thimerosal-containing vaccines cause autism; or that MMR vaccines can cause autism.

Separate opinions covered the Snyder, Hazelhurst, and Cedilllo test cases, but each represent the first, and major, theory, that the vaccines and thimerosal somehow combine to cause autism. The three cases involved some 5,000 pages of transcripts, 939 medical articles and 50 expert reports. The vast majority of credible scientific studies have shown — and all federal health agencies have strenuously argued — that there is no connection between vaccines and autism. And public health officials have repeatedly warned that fewer immunizations will endanger children. Indeed, at least in part because of the scare, about one in 12 children does not receive the MMR vaccine in the United States.

The Cedillos contended that their daughter fell sick a week after she received an MMR shot when she was about 16 months old. Today, at age 14, she requires round-the-clock care, suffers from seizures, has lost nearly all her vision and has constant abdominal pain.The Court found that the Cedillos have been misled by physicians who are guilty, in the Court’s view, of gross medical misjudgment on the issue of causation.

The Snyders argued that the MMR vaccine, or the mercury-based preservative in it, had triggered in their son pervasive developmental disorder — part of the autism spectrum. But, the Court found that the experts contending there is no link between autism and vaccines were far more qualified, better supported by the weight of scientific research and authority, and simply more persuasive on nearly every point in contention.

In the Hazlehurst claim, parents alleged that the MMR vaccine had caused “regressive autism” in their son. Agreeing with the other special masters, the Court found their causation evidence fell short, concluding that the combination of the thimerosal-containing vaccines and the MMR vaccine are not causal factors in the development of autism and therefore, could not have contributed to the development of their child’s autism. The weight of the presented evidence that is scientifically reliable and methodologically sound does not support petitioners’ claims.