Panel finds no autism-vaccine tie

An examination of scientific studies worldwide has found no convincing evidence that vaccines cause autism, according to a committee of experts appointed by the Institute of Medicine.

In particular, no link was found between autism and the measles-mumps-rubella vaccine or vaccines that contain a mercury preservative called thimerosal. The committee released its eighth and final report on Tuesday in Washington.

Some parents of autistic children immediately protested. Mark Blaxill, the father of an 8-year-old girl with autism, said the committee's conclusions were premature. Studies are under way that should not be dismissed, said Blaxill, who is a director of the Coalition for SafeMinds, an advocacy group that finances research on the possible connection between autism and vaccines.

Rep. Dave Weldon, R-Fla., a physician who is an advocate for the parents, said the report was "based on preliminary, incomplete information and may ultimately be repudiated."

The report will not "put to rest the concerns of parents who believe their children were harmed" by vaccines, Weldon said.

Autism is a disorder of brain development that has been the subject of much publicity in recent years as parents and researchers hunt for its underlying cause or causes. The issue has been fueled by a rise in the number of children found to have autistic traits in the past decade, though experts disagree on how large the increase is.

Dr. Marie McCormick, a professor of maternal and child health at Harvard who led the investigation, said that most "parents should be reassured" and should not worry about getting their children vaccinated. In the meantime, she said, research on autism should focus on "more productive" areas, like genetic and environmental factors. The debate over vaccines and autism began five years ago when a British researcher, Dr. Andrew Wakefield, reported that a small number of autistic children had signs of measles infection in their intestines after getting the measles-mumps-rubella vaccine.

A separate dispute soon broke out when researchers noted that many childhood vaccines contained a mercury preservative, though the measles formulation was not among them. Could an increase in the number of mercury-containing vaccines given to infants be an underlying cause of increased rates of autism?