Analysts defend vaccine injury program's approach to evidence

Sep 27, 2011 (CIDRAP News) – The US Vaccine Injury Compensation Program (VICP) sets a lower bar for evidence of vaccine-related harm than would be accepted in civil courts, but that's what it takes for the program to succeed in helping to protect the vaccine supply, according to a report by two Canadian analysts.

The article focuses on the VICP's recent handling of more than 5,000 claims that vaccines led to autism spectrum disorders in children. Though the program ruled against those claims, the authors say that some vaccine advocates have criticized the program for using "an overly permissive evidentiary test for causation" and lending credence to "insupportable accusations of vaccine harm."

The piece, published by the American Journal of Public Health, was written by Jennifer Keelan, PhD, of the Dalla Lana School of Public Health, University of Toronto, and Kumanan Wilson, MD, MSc, of the Ottawa Hospital Research Institute at the University of Ottawa.

The VICP was established by a 1986 law designed to protect vaccine makers from most lawsuits alleging vaccine-related injury, while giving people claiming such injuries an opportunity to get a fair hearing and potentially receive compensation from the government. Compensation funds come from a tax on vaccines. The law made it harder for plaintiffs to prove claims that healthcare providers failed to warn of adverse events.

The program was prompted by concerns that the whole-cell pertussis vaccine—since discontinued—could cause encephalitis and seizures, which led to an "avalanche" of lawsuits and caused many companies to stop making vaccines, the article explains.

The VICP is "designed to err on the side of compensating injury cases even when an evidence based analysis or consensus medical opinion would reject a causal relationship," write Keelan and Wilson. "It is not only justified and entirely appropriate for the evidentiary standards to be comparatively permissive but also arguably necessary to fulfill the program's policy mandate."

Under the VICP, claims of vaccine injury are heard by the US Court of Federal Claims. In the autism proceedings, the thousands of claims ultimately were grouped according to two broad biological theories of harm that they offered: (1) that the combination of the measles-mumps-rubella (MMR) vaccine and the preservative thimerosal caused neurologic harm in children, and (2) that thimerosal alone led to autism. The court heard six test cases to thoroughly examine those theories.

In decisions issued in July 2009 and March 2010, the court ruled against compensation for any of the six test cases, the article notes. Two of the cases went to an appeals court, which upheld the claims court's decisions. But in a case separate from the omnibus proceedings, one involving a child who suffered developmental regression and a seizure disorder after vaccination, was settled out of court. The reasons for setting the case were not divulged, but the outcome suggests there was a belief that the parents' case would have met the court's criteria for establishing causation, the article says.

Those criteria have grown out of rulings by the appellate judges in VICP cases and are in keeping with the spirit of the 1986 law, "which was designed to make it easy for parents who presented a reasonable case to receive compensation and to give those injured the benefit of the doubt," the authors say. They note that in the past few years, more than 70% of all cases reviewed—aside from the autism cases—led to compensation.

They explain that three main criteria for showing causation are used: (1) a medical theory causally connecting the vaccination and the injury, (2) a logical sequence of cause and effect showing that the vaccination led to the injury, and (3) a close temporal relationship between the vaccination and the injury. In addition, petitioners must show that the bulk of the evidence does not favor any other cause for the injury.

In civil lawsuits, by contrast, those claiming injury must offer "expert opinion based on epidemiology or rigorous scientific research establishing both general and specific causation," the report says. In addition, rules concerning admissible evidence and expert testimony are more stringent in civil courts. And the burden of proof in VICP cases is "balanced between the plaintiff and the government," whereas in civil cases it falls entirely on the plaintiff, the authors say.

They argue that if the vaccine court had the same evidence standards as civil courts, petitioners would be more likely to file civil lawsuits, since damage awards in that arena are potentially greater. Also, plaintiffs who fail to win compensation in the VICP are unlikely to go to the civil courts, with their tougher standards. The compensation program thus "will likely divert hundreds if not thousands of autism cases from proceeding to civil litigation," the article says.

Wilson and Keelan also note that the VICP pays plaintiffs' legal fees even if they don't prevail, which "serves a democratic function that allows claimants access to the legal system to air their concerns about immunization, which in many states is a government-mandated practice (and a public good)."

The authors reject the notion that VICP outcomes have somehow contributed to the belief that vaccines cause autism. Some obviously will not be persuaded, but for many people who may be concerned and uncertain about vaccines, "the courts' deliberations represent a comparatively neutral exhaustive examination of the available evidence," they write.

They conclude that the Omnibus Autism Proceedings have been the most important test for the VICP and that the courts have "largely succeeded in their objectives." Any changes in how the courts function, they assert, could change the "delicate balance" between providing just compensation to those claiming injury from vaccines and protecting vaccine manufacturers.

Keelan J, Wilson K. Balance vaccine science and national policy objectives: lessons from the National Vaccine Injury Compensation Program Omnibus Autism Proceedings. Am J Public Health 2011; early online publication Sep 22 [Abstract]

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