In three separate rulings(www.uscfc.uscourts.gov) issued March 12 in the U.S. Court of Federal Claims, federal judges have again ruled there is no association between vaccines and autism. The judges ruled that petitioners had failed to show that thimerosal-containing vaccines caused autism in the children involved in the cases, and they denied the families compensation.
The rulings were similar to those issued in three cases last year when special masters in the same court rejected the theory that the measles, mumps and rubella, or MMR, vaccine and thimerosal-containing vaccines can combine to cause autism.
Doug Campos-Outcalt, M.D., M.P.A., the AAFP's liaison to the CDC's Advisory Committee on Immunization Practices, or ACIP, said the rulings could help convince some vaccine-resistant parents to immunize their children.
"It depends on the parents," said Campos-Outcalt, who is associate head of the department of family and community medicine at the University of Arizona College of Medicine, Phoenix. "Ardent anti-immunizationists, who are small group, are unlikely to be swayed. It should help with the larger number of parents who are in the 'concerned' group and often see misinformation."
The rulings are the latest in a mounting body of evidence against those who claim vaccines cause autism. In February, The Lancet fully retracted a 1998 study that linked autism to the MMR vaccine after an independent panel concluded that the study was flawed and its lead author's conduct was "dishonest, irresponsible and misleading."
As in last year's rulings -- which were upheld on appeal -- the Special Masters were critical of the expert witnesses and studies presented by the petitioners.
Special Master Patricia Campbell-Smith wrote in her ruling that "the theory of vaccine-related causation is scientifically unsupportable."
"The scientific validity of the studies on which the petitioners rely has been questioned, and the conclusions drawn from the studies have been criticized as unsupported," she said.
Similarly, Special Master Denise Vowell said the petitioners had "relied on practitioners and researchers who peddled hope, not opinions grounded in science and medicine."
Vowell also noted that numerous government agencies and medical organizations -- including the AAFP -- have concluded there is no causal connection between vaccines and autism.
Jonathan Temte, M.D., Ph.D., a professor in the department of family medicine at the University of Wisconsin School of Medicine and Public Health, Madison, and a member of the ACIP, said it was important to note that the burden of proof needed to establish causality of harm in the vaccine court is significantly lower than the burden of proof required in civil court cases or to make medical decisions or recommendations.
"They have a very low burden of evidence for a case to go in their favor, but the court was not very impressed with the evidence they presented," Temte said. "That the plaintiffs could not surmount even this lowered standard of evidence is highly reflective of the evidence base for vaccine-induced autism."