Federal health officials said on Thursday the government has not conceded that vaccines cause autism even after a Georgia girl won federal compensation in a case arguing a vaccine led to her brain damage.

Hannah Poling, 9, had a rare mitochondrial disorder and a federal court ruling said regular childhood vaccinations may have contributed to some of her autism-like symptoms. She was awarded compensation under the National Vaccine Injury Compensation Program in a case that became public this week.

Some activists who argue vaccines can trigger autism jumped on the case as vindication of their cause. But Dr. Julie Gerberding, director of the U.S. Centers for Disease Control and Prevention, denied this.

"Let me be very clear that (the) government has made absolutely no statement about indicating that vaccines are a cause of autism," Gerberding told reporters in a telephone briefing.

"That is a complete mischaracterization of the findings of the case, and a complete mischaracterization of any of the science that we have at our disposal today. So I think we need to set the record straight on that."

The vaccine injury program is a no-fault system that has a $2.5 billion fund built up from a 75-cent-per-dose tax on vaccines. It was set up to ensure companies would not be afraid to make vaccines, and to provide injured children an easier way to seek compensation.

Thousands of lawsuits have been filed by parents who argue their children have autism caused by vaccines.

The Institute of Medicine, an independent organization set up to inform U.S. policy, has found there is no evidence that vaccines can cause autism. Many recent studies have come to the same conclusion.

PRESERVATIVE EYED

Some autism advocacy groups argue that a mercury-containing preservative in vaccines called thimerosal can cause autism.

Republican presidential candidate Sen. John McCain entered the debate last week, saying there is "strong evidence" linking autism to a thimerosal.

Dr. Edwin Trevathan, director of the CDC's National Center on Birth Defects and Developmental Disabilities, said the Poling case did not demonstrate any link between vaccines and autism.

"I think it's also worth noting that most children with autism do not seem to have a mitochondrial problem," he told the briefing.

"So this association between mitochondrial disorders and autism is actually probably relatively rare. But the association between mitochondrial disorders and severe brain damage and dysfunction is one that is not as rare and is actually quite important."

Trevathan said it is not clear whether a fever caused by a vaccine might further stress a child with such a condition, causing autism-like symptoms.

Autism can have relatively mild symptoms or can severely disable a child by interfering with speech and behavior. No one knows what causes it.

The CDC estimates that about one in every 150 children has autism or a related disorder such as Asperger's syndrome -- 560,000 people up to age 21 in the United States.

"Our message to parents is that immunization is life-saving. There's absolutely nothing changed in the adamant recommendations that we are making to get children vaccinated," Gerberding said.