For the second time this year, families claiming that vaccinations triggered autism in their young children will head to a federal court to determine whether they are eligible to collect damages from the government.
The case, which begins today, offers two 10-year-old boys from Portland, Ore. — William Mead and Jordan King — as test cases for the theory that thimerosal-containing vaccines, on their own, cause autism.
Lawyers for these families maintain that the boys were developing normally until they were exposed to vaccines containing thimerosal, a preservative containing mercury. After receiving these vaccinations, the attorneys say, the boys began to show symptoms of autism — a developmental disability characterized by difficulty in communicating and interacting with others.
The theory that thimerosal is singularly culpable in bringing about autism is only one of three upon which courts will decide. In 2007, hearings were conducted in three test cases intended to examine whether the combination of measles-mumps-rubella (MMR) vaccines containing thimerosal cause autism. And later this year, attorneys will present four more test cases to determine whether MMR vaccines, regardless of whether or not they contain thimerosal, may bring about the condition.
Each of these theories challenge the position held by the mainstream medical community that vaccines, whether they contain thimerosal or not, do not cause autism — a position that a majority of scientific studies support.
In 2004, a panel convened by the Institute of Medicine concluded there was no credible evidence that the thimerosal in vaccines led to autism. Still, since 2001, the ingredient has been removed from most vaccines, save for certain influenza shots, in response to autism fears.
Still, attorneys for the families involved need only show that it is more likely than not that thimerosal-containing vaccines caused the boys' injuries.
If successful, the families could receive compensation for past and future medical expenses, special education expenses and up to $250,000 for pain and suffering, among other monies. The final decision, which could take up to several months to arrive, may be appealed by either the families or the federal government.
The case at hand, as well as other cases involving possible injury brought about by a vaccine, are handled under the National Childhood Vaccine Injury Compensation Program enacted in 1986. The program set up a no-fault system in which people with grievances could file injury claims against the federal government rather than sue the companies that made the vaccine or the health-care providers who administered it.
A "special master" appointed by the U.S. Court of Federal Claims reviews these cases to determine whether vaccines were more likely the cause of the injury at hand. If the government chooses not to rebut the claim by showing that the vaccine probably was not responsible for the injury, the claim is approved and an award is made.
The legal standard set by this system is therefore a much lower bar than the demands of medical validity, which would require a much greater magnitude of evidence to draw the conclusion that vaccines were in any way responsible for an injury.
Lawyers have chosen nearly 4,900 families — each of which claim that the mercury-containing preservative thimerosal in vaccines brought about autism and other developmental disorders in their children — in an effort to seek this compensation from the government.
Past studies in Denmark, and more recently California, have suggested that thimerosal was not to blame, as reported cases of autism have continued to increase after the removal of thimerosal from most vaccines.
Dr. Pauline Filipek, associate professor of clinical pediatrics and neurology at the University of California Irvine School of Medicine, and her colleagues are researchers who are among those looking into a possible connection.
"Mercury has long been known to be a mitochondrial toxin, and could potentially interact with underlying genetic vulnerability of deficient mitochondria," she said. "That said, there remains no epidemiological data that we are aware of that implicates vaccination in autism or in mitochondrial disorders."
Boyd Haley, a chemist at the University of Kentucky and vocal proponent of a vaccine-autism link, believes the current studies are flawed. And he said that he believes this case, as well as most other cases of autism, are indeed the result of an underlying genetic vulnerability being triggered by the mercury that used to be present in vaccines.
"I am very pro-vaccine," Haley said. "I strongly believe in vaccination. I just believe that they ought to be safe and they ought to be tested."
Specifically, Haley said certain genetic conditions may make some children unable to effectively manufacture glutathione, a protein he says would allow them to clear substances such as mercury from their systems. Autism, he said, could be the result.
But Dr. William Schaffner, professor and chairman of preventive medicine at Vanderbilt University in Nashville, Tenn., countered that this opinion demonstrates one of many hypotheses behind the development of autism in some children. Some of these hypotheses, he said, are being investigated. But none so far, he noted, have the weight of scientific proof.
"The theory, that there may be underlying genetic defect that results in or can be somehow activated by some environmental process or insult, and that this in turn leads by some biological mechanism to autism is a valid theory, and it is a theory being pursued by the autism research community," Schaffner said.
"But any subset of this theory is a hypothesis, and you don't draw conclusions from a hypothesis."
The case follows a legal ruling in early March in which a special master appointed by the U.S. Court of Federal Claims determined that the family of 9-year-old Hannah Poling of Athens, Ga.. was entitled to receive an as yet undetermined award from the no-fault fund.
In this case, government health officials acknowledged that a vaccine, by worsening an underlying genetic condition, may have triggered autism-like symptoms in the girl. But federal health authorities at the time emphasized that the concession should not be interpreted to mean that vaccines cause autism.
"The government has made absolutely no statement about indicating that vaccines are the cause of autism, as this would be a complete mischaracterization of any of the science that we have at our disposal today," said Dr. Julie Gerberding, director of the U.S. Centers for Disease Control and Prevention during a March 6 news conference on the Poling case. "I think we need to set the record straight on that."
Still, the case was viewed as an important milestone by autism groups that maintain that vaccinations are connected to autism.
"I wanted to know why my daughter, who had been completely normal until she received [five vaccines for nine different diseases], in one day was no longer there … no longer responding," Hannah's mother Terry Poling told the crowd of reporters present on the steps of a U.S Federal Court in Atlanta on March 6.
The Polings said Hannah received the battery of vaccines in 2000, when she was 19-months-old. Shortly after these shots, they said she suffered from a fever that left her screaming and arching her back. Following this, they said, Hannah began showing classic signs of autism — staring at lights, running in circles and staring at fans.
"I think that Hannah's case … is echoed among thousands of similar cases," Hannah's father Dr. Jon Poling, who is also a neurologist, told Chris Cuomo on ABC's Good Morning America. "I know a lot of other medical experts are going to get out there and say this is a very unusual, oddball case. We don't really think it is at all."
But health experts worry that fears about the use of vaccines could expose children to risk of sickness or death from other conditions, including measles and polio.
"These diseases that affected childhood are now not known by this generation of parents, so there's no balancing of concern," Schaffner said.
"Without vaccination, these disease will return, and they will spread."
Associated Press reports contributed to this story.