Two families sought compensation under the National Vaccine Injury Compensation Program for injuries to their children allegedly caused by the Diptheria–Tetanus–acellular Pertussis (DTaP) vaccine. Both families claimed that the DTaP vaccine caused their children to develop severe myoclonic epilepsy of infancy (SMEI), a seizure disorder associated with developmental delays. In both cases, the children developed a febrile seizure immediately after receiving DTaP vaccinations, but were not diagnosed with SMEI for several months.
The appellate court upheld a special master's findings that a gene mutation was solely responsible for the DTaP vaccine recipients’ injuries, and that the only harm caused by the DTaP vaccination was a single, isolated, initial febrile seizure.
Under the National Vaccine Injury Compensation Program, in cases involving injuries that do not fall within the Vaccine Injury Table, referred to as “off-Table cases,” claimants have the burden to prove causation by a preponderance of the evidence. To prove causation, a claimant must show that the vaccine was not only a but-for cause of the injury but also a substantial factor in bringing about the injury.
The court noted that interpretations of the Vaccine Act have given rise to some confusion as to the order of proof regarding causation in off-Table cases. In particular, the question has arisen whether, in assessing whether a prima facie showing of causation has been made in an off-Table case, a special master may consider evidence of other possible causes for the injury in question, or whether evidence of other possible causes may be considered only in connection with the “factors unrelated” defense on which the government has the burden of proof. The court resolved this question in favor of allowing special masters to consider the record as a whole in determining causation. Also, the special master may not require the petitioner to shoulder the burden of eliminating all possible alternative causes in order establish a prima facie case. In order to prevail in a National Childhood Vaccine Injury Act (Vaccine Act) case, a petitioner need not provide proof of the specific biological mechanism leading to the injury at issue. The special master may find that a factor other than the vaccine caused the injury only if that finding is supported by a preponderance of the evidence.
See: Stone v. Secretary of Health and Human Services, 2012 WL 1432525 (Fed.Cir. Apr 26, 2012) (not designated for publication).