Third Circuit Rejects Vaccine Plaintiffs' General Causation Expert Opinion
The Third Circuit recently upheld a judgment for the U.S. following a bench trial, in a suit by a couple who alleged that contaminated polio vaccine caused the husband's brain cancer. Gannon v. United States, 2008 WL 4151665 (3d Cir. 2008).
Plaintiffs alleged that an oral polio vaccine (OPV) received between 1973 and 1976 was contaminated with SV40, a simian virus found in both monkeys and humans. The Gannons claimed that the government was negligent in failing to prevent the manufacturer from making the OPV available to the public, and as a result, the contaminated vaccine caused Mr. Gannon to develop a form of brain cancer. Gannon and his wife filed an administrative claim against the government under the Federal Tort Claims Act and, later, a suit in the Eastern District of Pennsylvania.
The Court, for the convenience of the witnesses and to prevent recalling the experts later in the trial, decided to combine a Daubert hearing with the expert bench trial testimony on the issue of causation. Thus, the trial began with the Daubert examination of plaintiffs' expert, Dr. Adi Gazdar, who presented his full testimony on the issue of causation. He testified that SV40 plays a causal role in this type of cancer.
The district court denied the Daubert motion, but rejected the testimony as insufficient on the issue of general causation. Safe approach in a bench trial, here it and then decide. The ruling came pursuant to Rule 52(c), which states that a trial court can enter judgment after hearing evidence on only one issue, provided the party against whom judgment has been entered is fully heard. (The appeals court rejected the plaintiffs' argument that they were not fully heard on causation: The plaintiffs asserted they would have called two other witnesses to testify, but those witnesses were not relevant to causation because their testimony would principally address the issue of contamination.) Interestingly, the United States did not offer an alternate source of causation but merely asserted that SV40 did not cause brain tumors and offered expert testimony to that effect.
Although Dr. Gazdar testified that it was his opinion that to a reasonable degree of medical certainty SV40 plays a causal role in the formation of medulloblastomas, the Court decided that the plaintiffs had not met their burden of proof on causation. Specifically, the Court found that Dr. Gazdar's testimony failed to satisfy the “Bradford Hill” criteria. The Bradford Hill criteria are broadly accepted criteria for evaluating general causation based on epidemiology; they are: (1) Strength of Association, (2) Consistency, (3) Specificity, (4) Temporality, (5) Biologic Gradient, (6) Plausibility, (7) Coherence, (8) Experimental Evidence, and (9) Analogy.
On appeal, the Third Circuit observed that causation is an essential part of the plaintiffs' negligence claim. Based upon its thorough consideration of the record evidence, the Third Circuit could not say that the district court clearly erred in its findings of fact or that it erred in concluding that the Gannons had not met their burden of proof on the issue of causation.
- The Court relied upon the fact that all three defense experts used established scientific frameworks and cited both biological and epidemiological evidence. Each of those experts opined that the evidence did not support the conclusion that SV40 causes human cancer.
- The Court relied upon a 2003 Institute of Medicine report, which concluded that “ ‘the evidence is inadequate to accept or reject a causal relationship’ “ between SV40 and cancer.
- Dr. Gazdar, the plaintiffs' expert, testified that he agreed that current epidemiological evidence does not support the conclusion that SV40 causes brain cancer.
- He relied upon testing on rodents, which defense experts stated were not a good brain model for humans; even Dr. Gazdar admitted the results could not necessarily be extrapolated to humans.
Most importantly, the court considered each of the nine Bradford Hill criteria for causation and found that Dr. Gazdar's opinion did not meet the criteria. The general causation opinion was thus rejected on the merits.
