Health officials strongly denied Thursday that there is a link between childhood vaccines and autism, calling the case in which a 9-year-old Athens girl was injured "a very special situation."

The Centers for Disease Control and Prevention held a teleconference to address concerns raised after the federal government conceded that Hannah Poling was injured in 2000 by a series of vaccinations that resulted in her developing autism. The child has a genetic disorder involving her mitochondria, which supply energy to cells, that was aggravated by the series of vaccinations.

The federal government "made absolutely no statement indicating that vaccines are a cause of autism," said CDC Director Julie Gerberding. "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."

She called Hannah's case "a very special situation and a very sad situation for the family of the affected child."

However, the announcement had been viewed by many advocates as proof of their assertion that the dramatic rise in autism in the U.S. in recent decades is due to thimerosal, a preservative once used in many vaccines.

Though it has now been removed from childhood vaccines, there are nearly 5,000 claims of injury, many associated with autism, pending before the same federal vaccine injury compensation program that conceded the Polings' claim.

Maurine Meleck, of North Augusta, who has two of those claims, said her two grandsons both suffered some degree of autism because of the shots and one only began to recover when she stopped his vaccinations. She was not surprised at the denials.

"We're used to the spin," she said. "It's just a shame."

Ms. Meleck claimed the vaccines actually cause the mitochondrial disorder and that half of the children with autism have it, something health officials also disputed.

The mitochondrial disorders are most often caused by genetic lesions in the mitochondria itself, said Dr. Tom Insel, director of the National Institute of Mental Health. How a vaccine could cause that kind of disorder "would be a little difficult to imagine," he said.

Most children with mitochondrial disorders do not have autism, said Edwin Trevathan, director of the National Center on Birth Defects and Developmental Disabilities at the CDC. And while a physician would have to weigh the risks and benefits of immunizing that child, the vaccine recommendations are the same for those with the disorder, he said.

Children with these disorders might appear normal but under severe stress, such as from a high fever, the child's body cannot compensate with the energy they need, he said. The brain is often affected and they suffer neurological disorders as a result, such as seizures.

In fact, many pediatric neurologists recommend children with the disorder get the vaccines because the diseases they help prevent "are infections that are known to be associated with severe regression in children who have mitochondrial disorders," Dr. Trevathan said.

The Associated Press contributed to this report.