In a major setback for the fight to link autism to vaccines, a special federal court ruled Thursday that the measles-mumps-rubella vaccine and vaccines that contained a mercury-based preservative were not connected to the autism that developed in three children.
The decisions in the cases of the Cedillo, Hazlehurst and Snyder families could potentially sink the claims of several hundred other families in an omnibus proceeding that believe the MMR vaccine alone or in combination with vaccines containing the preservative thimerosal caused their children's autism, said Curtis Webb, a lawyer for the Hazlehurst family.
The outlook appeared particularly grim for them because these three cases were considered among the strongest, Webb said.
"We're extremely disappointed," Webb said. "It wasn't even a close case."
The families' attorneys are considering appealing, the lawyer said, but first need to study the decisions carefully.
Vaccine supporters and public health experts applauded the decision by the U.S. Court of Federal Claims, hoping it would reassure parents that the shots recommended by federal scientists are safe.
"It's a great day for science and I'd like to think it's also a great day for children with autism," said Dr. Paul Offit, chief of infectious diseases at Children's Hospital of Philadelphia and co-inventor of the rotavirus vaccine (a standard childhood immunization that does not contain thimerosal).
Offit said he understood that many parents had been scared by the controversy, but believed that those who refused to vaccinate their children contributed to a 12-year high in measles cases last year and a recent outbreak of bacterial meningitis. Both of these outbreaks could have been prevented by standard childhood vaccinations, he said.
"It's time to put the vaccine hypothesis aside and focus on the real causes of autism and not be diverted by a dead end," said Offit, who was not involved in the case.
Congress set up the special vaccine court in 1986 when pharmaceutical companies faced a liability crisis. Vaccines were being blamed for catastrophic injuries to children, and some vaccine manufacturers threatened to quit the business.
The court shields vaccine makers from damage claims, drawing money from a pool funded by a surcharge levied on every vaccine. Parents who believe their children have been harmed by vaccines can file petitions at this court and receive compensation from the pool.
About 5,000 families have filed claims involving autism, a spectrum of developmental disorders whose hallmarks are impaired social interaction and communication. The judicial officers appointed in this case, known as special masters, decided to hear test cases on different causation theories to develop general principles that they could apply to the flood of claims.
Three special masters heard the cases of the Cedillo, Hazlehurst and Snyder families in 2007. In general, lawyers for the families argued that vaccines containing thimerosal weakened the children's immune systems, allowing the viruses in the MMR vaccine to take hold and cause autism. In the Hazlehurst case, lawyers for the family came to argue that the MMR vaccine was the primary culprit.
Thimerosal was used to keep bacteria from growing in multidose containers. The MMR vaccine has never contained thimerosal, but some other routinely recommended vaccines such as the hepatitis B vaccine did. Thimerosal was phased out of most shots by 2000. Trace or small amounts of thimerosal remain in a few vaccines recommended for children, including the flu shot.
The special masters rejected practically all of the families' arguments.
"I concluded the evidence was overwhelmingly contrary to the petitioners' contentions," George Hastings Jr. wrote in the Cedillo opinion, similar to the others. "The expert witnesses presented by the respondent were far better qualified, far more experienced and far more persuasive than the petitioners' experts."
He expressed "deep sympathy and admiration" for the family, but said: "I must decide this case not on sentiment, but by analyzing the evidence."
He added: "While Michelle Cedillo has tragically suffered from autism and other severe conditions, the petitioners have also failed to demonstrate that her vaccinations played any role at all in causing those problems."
Several parent-advocates were frustrated by the rulings.
"I'm sure the decision was based on some of the current science that is out there and the scientific community hasn't invested in the types of independent research necessary to get to the bottom of the issue," said Rick Rollens of Sacramento, who has an autistic son and co-founded the UC Davis MIND Institute.
Rollens and others said these verdicts wouldn't make parents stop questioning the safety of vaccines, especially when the parents see changes in their children right after vaccination.
"There's no denying what happens to your child when you see it firsthand," said Rollens. "Maybe we haven't asked all the right questions yet."
The parent-advocates held out hope that the government might still acknowledge connections between vaccines and autism through other mechanisms. Last year, they pointed out, the Department of Health and Human Services concluded that vaccines aggravated an underlying metabolic disorder in Hannah Poling, a young girl from Georgia who developed a brain disorder with features of autism.
The special masters are still working on another group of test cases alleging that thimerosal itself causes autism. Final briefs are still being filed, with decisions expected sometime after this summer.
Thursday's decisions "won't resolve the thimerosal cases," said Webb, the lawyer. "There are more people that focus on thimerosal than focus on MMR. . . . Those cases are still viable."