Friday's ruling is far from the first defeat handed to the parents of approximately 5,000 children who claim that vaccines containing the mercury-based preservative thimerosal led to the development of autism spectrum disorders in their children. In a similar case before the court in February 2009, the court discounted parents' claims that the Measles-Mumps-Rubella vaccine (MMR) and thimerosal caused autism and even questioned the integrity of their medical and legal advisers. Another subsequent issue, a hypothesis that MMR vaccine alone could cause autism, was voluntarily dismissed.
The weight of scientific evidence in recent years has overwhelmingly refuted a connection between childhood vaccines and autism. In 2001, a study showed that autism incidence has risen since thimerosal was removed from childhood vaccinations. In 2003, an Institute of Medicine (IOM) report concluded that no association exists between thimerosal and autism. And last month, the Lancet officially retracted the 1998 paper by Dr. Andrew Wakefield that served as a central pillar for the idea that vaccines and autism are somehow linked.
But despite the majority of current literature that refutes this association, including a January 2010 statement by the CDC and 2004 statement by the IOM, many parents who believe in a connection between autism and vaccines are unlikely to change their minds or accept the court's finding. Fears may still linger among parents in general as well, research shows. A survey in the journal Pediatrics on March 1 found that 90 percent of parents with minor children agreed that vaccines protected from disease, but 25 percent also indicated that they thought vaccines might cause autism.
ABC's John Donvan, Brian Hartman, and Reynolds Holding contributed to this report.