A Department of Justice special court will hand down rulings Thursday in cases asking whether certain vaccines cause autism, the lead plaintiffs' attorney told CNN Wednesday.
A panel of "special masters" will issue decisions on three test cases heard in 2007 involving children with autism that their parents contend was triggered by early childhood vaccination, said attorney Thomas Powers.
The parents seek compensation, saying the "combined" exposure to thimerosal, a mercury-containing preservative, in some vaccines and the MMR vaccine led to autism, he said.
The three families -- the Cedillos, the Hazelhursts and the Snyders -- have been notified of the development, as have the more than 180 lawyers collectively representing the 4,800 families with claims in the Vaccine Court Omnibus Autism Proceeding, Powers said.
At 14, Michelle Cedillo can't speak, wears a diaper and requires round-the-clock monitoring in case she has a seizure. Her parents say their only child was a happy, engaged toddler who responded to her name, said "mommy" and "daddy" and was otherwise normal until at 15 months she received a measles, mumps and rubella (MMR) vaccine combined with thimerosal, found in that and other vaccines a the time.
The other two families described similar alterations in their children's development after receiving vaccinations in their first two years of life.
The government argued during the 2007 bench trials that the plaintiffs' claims linking the vaccines with autism are not supported by "good science."
Likewise, the Centers for Disease Control and Prevention, the World Health Organization and the Institute of Medicine have found no credible link between vaccinations and autism.
Powers' litigation steering committee is representing thousands of families that fall into three categories: those that claim MMR vaccines and thimerosal-containing vaccines can combine to cause autism; those who claim thimerosal-containing vaccines alone can cause autism; and those who claim MMR vaccines, without any link to thimerosal, can cause autism.
Thursday's rulings will only affect the families that fall under the first category, Powers said.
Since 2001, thousands of parents with autistic children have filed petitions seeking compensation with Vaccine Injury Compensation Program at the Department of Health and Humans Services.
By mid-2008, more than 5,300 cases were filed in the program -- 5,000 of those await adjudication, according to the agency.