(CNN) -- (CNN) -- A special court ruled Thursday that parents of autistic children are not entitled to compensation in their contention that certain vaccines caused autism in their children.
A special court denied Mike and Theresa Cedillo's claim that vaccines caused autism in their daughter, Michelle.
1 of 2 "I must decide this case not on sentiment, but by analyzing the evidence," one of the "special masters" hearing the case said in denying the families' claims, ruling that the families had not presented sufficient evidence to prove their allegations.
The decisions came in three test cases heard in 2007 involving children with autism that their parents contend was triggered by early childhood vaccinations.
The three families -- the Cedillos, the Hazlehursts and the Snyders -- were notified Wednesday that a decision had been reached, as were the more than 180 lawyers collectively representing the 4,800 families with claims in the Vaccine Court Omnibus Autism Proceeding, said lead plaintiffs' attorney Thomas Powers.
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 several vaccinations -- one for measles, mumps and rubella, and others that contained thimerosal, a mercury-based preservative.
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 who 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 of children with autism have filed petitions seeking compensation with the Vaccine Injury Compensation Program at the Department of Health and Human Services.
By mid-2008, more than 5,300 cases were filed in the program. Five thousand of those are awaiting adjudication, according to the agency.