Last Friday, the U.S. Court of Appeals for the Federal Circuit affirmed the second of the three defense verdicts in the test cases alleging that the measles-mumps-rubella vaccine causes autism. Cedillo v. Secretary, HHS, No. 2010-5004, slip op. (Fed. Cir. Aug. 27, 2010). Although the Cedillo decision turns on the specific facts of the case and does not contain an across-the-board rejection of the vaccines-cause-autism theory, Cedillo adds to the growing body of decisions rejecting this theory.

As we told you in May, the plaintiff in the first vaccine/autism case decided by the Federal Circuit abandoned on appeal the widely discredited theory that thimerosal causes autism. The plaintiffs in Cedillo clung to a version of that theory but with no better results.

The plaintiff parents contended that the ethyl mercury in thimerosal damaged their daughter’s immune system, which made her body unable to clear the measles virus found in the MMR vaccine. As a result, they claimed, the measles virus persisted in her body and caused autism and other medical problems. Slip op. at 4-5. To establish that this theory could apply specifically in their daughter’s case, plaintiffs had to prove that she had the measles virus in her body, and they offered test results from a for-profit, non-accredited laboratory called Unigenetics, which is no longer in business. The Special Master found those test results unreliable for many reasons. Without this key piece of evidence, plaintiffs could not prove specific causation, and they lost for that reason alone. For good measure, the Special Master also rejected plaintiffs’ general causation theory. The Court of Federal Claims affirmed. Id. at 8-10.

On appeal, the Federal Circuit upheld the Special Master’s conclusion that the Unigenetics test results were unreliable. Plaintiffs concentrated their appellate fire on the admission of evidence from a government expert whose underlying data was not disclosed to them, but the court found the admission of that evidence was not error for many reasons specific to the procedural Vaccine Rules and the facts of this case. Id. at 14-22. In any event, the court held, the Special Master had said that he would have reached the same decision even without this expert’s testimony, so the lack of disclosure didn’t really matter. Id. at 21-22. Since plaintiffs’ specific causation theory was based on the presence of measles virus in the child’s body, the court affirmed the rejection of plaintiffs’ claim. Id. at 22. The court therefore concluded that it need not address the other grounds for the Special Master’s decision – e.g., general causation. Id.

Because we think the vaccines-cause-autism theory is based on junk science and harms public health by giving some people a reason not to have their children vaccinated, we would prefer a clear declaration from a federal appellate court rejecting this theory once and for all. But such categorical rulings are rare in the law. Courts are constitutionally, or perhaps Constitutionally, inclined to decide individual cases on their facts rather than the bigger questions lurking in those cases. In time, the answer to the larger questions becomes apparent from the answers to many individual questions. By rejecting another of plaintiffs’ many different attempts to show that vaccines cause autism, Cedillo makes it clearer than ever that this theory is bunk.