Relax, parents: Vaccine doesn't trigger autism

Immunity to measles not a factor, study finds

November 7, 2002

BY ADAM MARCUS
HEALTHSCOUT NEWS SERVICE

Danish scientists say they've found no link between the measles-mumps-rubella vaccine and autism, after looking at more than a half-million children to find one.

The possibility that the MMR vaccination triggers autism first surfaced in 1998, when British researchers reported on a dozen children who developed the condition and other behavioral problems shortly after getting immunized. Studies since then have failed to support the connection.

Last year, a report from the U.S. Institute of Medicine, an arm of the National Academy of Sciences, said "a consistent body of epidemiological evidence shows no association . . . between MMR" vaccine and autism. The World Health Organization, British health authorities, the American Academy of Pediatrics and other major medical groups have made similar statements.

Dr. Kreesten Madsen, the epidemiologist who led the latest research, said he hopes the findings will finally quash concerns about the alleged connection.

"The risk was the same for vaccinated and unvaccinated children," said Madsen, of the Danish Epidemiology Science Center in Arhus, Denmark. "Few studies can be said to be conclusive, but this one was state-of-the-art."

The researchers, whose results appear in today's issue of the New England Journal of Medicine, reviewed the medical histories of 537,000 children born in Denmark between 1991 and 1998. Of those, 82 percent received the MMR vaccine, which was introduced to Denmark in 1987 and is identical to the one available in the United States.

Information from national disease registries showed that 316 of the children developed autism, and 422 more developed similar behavioral disorders. There was no difference in the risk of either diagnosis among those who received the combined vaccine and those who did not.

Still, critics of the vaccine say they aren't swayed.

Barbara Loe Fisher, president of the National Vaccine Information Center, dismisses the Danish study as "numbers moved around on a piece of paper."

The issue "is not going away because Denmark has done an epidemiological study saying 'Don't worry about it anymore,' " said Fisher, who said her son developed neurological complications, though not autism, after receiving the MMR vaccine.

Fisher said the debate can only be settled by cell-level science that looks at the inoculation's effects on the immune system and the brain -- research she is convinced will prove a link between the MMR vaccine and autism.

The MMR vaccine uses live, weakened measles virus. But there's no known biological mechanism for measles virus to cause autism, said Dr. Marie McCormick, chairwoman of the Institute of Medicine committee that examined the MMR vaccine's alleged tie to autism.