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California and the West

Vaccine, Surge in Autism Unrelated, Study Says

Health: Rise in cases occurred while measles-mumps-rubella inoculation rate was constant. Critics discount the findings.

March 07, 2001|THOMAS H. MAUGH II | TIMES MEDICAL WRITER

The controversial idea that the dramatic upsurge in autism over the last two decades was caused by the measles-mumps-rubella vaccine--a concept embraced by many parents--is wrong, according to a new report released today by the California Department of Health Services.

The new study, like two others recently conducted in England and Finland, found that the rate of autism has been rising dramatically as the number of children vaccinated has remained virtually constant. This is convincing evidence, the researchers say, that the vaccine plays little or no role in the disease.

"We cannot rule out the possibility that in certain isolated, rare instances, the vaccine might have caused a rare case of autism," said Dr. Hershel Jick of Boston University Medical Center. "But it is certainly not the major villain."

Advocates of the autism-vaccine link dismiss the new reports, however, claiming bias on the part of their authors.

"I don't know why anyone would believe information that comes out of a branch whose sole purpose is to promote immunization in California," said Rick Rollens, a parent advocate who was instrumental in creating the MIND Institute for researching autism at UC Davis.

The studies in England and Finland are equally questionable, he added, because vaccine makers funded them.

And Dr. Bernard Rimland of the Autism Research Institute in San Diego argues that it is not the vaccine--known as MMR--alone that triggers autism, but the entire burden placed on the immune system by the 22 separate vaccines that are now given to children between birth and age 2.

"By focusing on MMR, these guys are missing the boat," he said. "It's much too early to dismiss the [vaccine] hypothesis."

Despite those qualms, the new findings seemingly put researchers back to square one in trying to unravel the causes for the astonishing surge in a once-rare disorder, which has increased more than 500% in the last decade alone.

Autism is a severe developmental disorder in which children seem isolated from the world around them. There is a broad spectrum of symptoms, but the condition is marked by poor language skills and an inability to handle social relations.

In the 1970s, studies showed the incidence of autism to be about one case in every 2,500 children. Today, various studies, though controversial, suggest that the incidence is one in every 250 children, and perhaps even higher.

Though most researchers are convinced that genetic susceptibility lies at the heart of the disorder, it has become clear that some triggering agent in the environment plays an equally important role, either during gestation or soon after birth.

Researchers are investigating toxic chemicals, viruses, drugs, dietary changes and a host of other potential factors.

The purported link to MMR was first proposed by parents of autistic children, like Rollens, who observed that their children were apparently developing normally until they received the vaccine, at which point their development stopped or regressed.

Their suspicions were fanned by a 1998 report by Dr. Andrew Wakefield of the Royal Free Hospital in London, who identified 12 children who had undergone such regression within 14 days of being given MMR. The children also had gastrointestinal problems similar to irritable bowel syndrome, and Wakefield said he had identified the weakened virus used in the measles vaccine in their intestines.

Wakefield has argued forcefully that the viral infection may have allowed some potentially toxic components of food to leach into the bloodstream and travel to the brain, where they damaged neurons and produced developmental problems. He will soon publish a larger study of 170 such children showing the same results.

His findings have produced a furor in England, where many parents have demanded that the three components of the MMR vaccine be given separately at different times. A group of parents has also sued the vaccine's manufacturer.

The new study, reported in today's Journal of the American Medical Assn., rebuts such claims. It relies on extensive record keeping by the California health department.

The number of autism cases each year was determined by admissions to the state's 21 regional centers for developmental disabilities, which provide special educational services to such children.

Vaccination data were obtained from yearly surveys of a random sample of kindergarten admissions, which yields birth dates and the dates of the immunizations required for school admission.

Dr. Loring Dales and his colleagues at the health department's Immunization Branch in Berkeley found that the proportion of children vaccinated with MMR before the age of 2 increased only 14% from 1980 to 1994, while the number of children diagnosed yearly with autism increased 572%.

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