According to CNN, the families filing claims fall into three categories: those alleging that MMR vaccines and vaccines containing thimerosal in combination can cause autism; those claiming that only thimerosal-containing vaccines can do such damage; and those who claim MMR vaccines not including thimerosal can cause autism.
Thursday's court ruling concerned only families in the first category, the news network said.
The U.S. National Institutes of Health says that one American child in 150 has been diagnosed with autism, although experts wonder if that increasing number is due in part to better diagnoses and a broader definition of the disorder.
The U.S. Centers for Disease Control and Prevention has more on childhood vaccinations.
SOURCES: Robert Frenck Jr., M.D., professor of pediatrics, Cincinnati Children's Hospital, member of the American Academy of Pediatrics' committee on infectious diseases; Barbara Trommer, M.D., associate director, Developmental Center, Maimonides Medical Center, New York City; James Moody, director, SAFE MINDS, and a director, National Autism Association, Nixa, Mo.; Feb. 12, 2009; news release, American Medical Association, Chicago; Feb. 12, 2009; news release, Autism Speaks, New York City; Associated Press; CNN