WASHINGTON - No evidence links autism to a mercury-based preservative once used in childhood vaccines or to measles-mumps-rubella shots, a panel of prominent scientists said yesterday after an extensive investigation.
The conclusion was a blow to parents of autistic children who blame vaccination for the brain disorder and are pressing for more research.
"The overwhelming evidence from several well-designed studies indicates that childhood vaccines are not associated with autism," said Dr. Marie C. McCormick, a Harvard University professor of maternal health and chairwoman of the panel that prepared the report for the Institute of Medicine, an arm of the National Academy of Sciences.
In the report, McCormick and 12 other experts said five epidemiological studies conducted in the United States and abroad consistently showed no link between vaccines containing the preservative thimerosal and autism, a severe neurological disorder. In addition, the panel reported that 14 large epidemiological studies showed no connection between autism and the measles-mumps-rubella vaccine.
Studies that purported to establish a vaccine-autism link either were seriously flawed or were inconclusive, the panel said.
The report amounted to a strong endorsement of the position of federal health officials and much of the U.S. medical establishment. Both have dismissed suggestions of a vaccine-autism link and have maintained that childhood vaccines are safe. The panel said it was proposing no changes in the current schedule of routine childhood vaccinations.
Curtis Allen, a spokesman for the Centers for Disease Control and Prevention, said the report "was consistent with past scientific findings."
Dr. Louis Z. Cooper, a Columbia University professor of pediatrics, said: "I think we should congratulate this committee for working very hard and with great expertise. It seems to me they left no stone unturned."
But Lyn Redwood, a leading critic of vaccines, said the panel had uncritically accepted the views of federal health officials and the vaccine industry.
"This committee and its report clearly chose to ignore groundbreaking scientific research on the mercury-autism link and instead the Institute of Medicine has issued a flawed, incomplete report that continues to put America's children at risk," said Redwood, president of the SafeMinds activist group and mother of an autistic son.
