VOLUME 37, NO. 15, April 17, 2001

Epidemiologists study autism-vaccine link

By Susannah Benady

QUEBEC – Leading epidemiologists from nine countries are meeting in London later this week to finalize plans for a major study to explain the exponential increase in autism over the past decade.
   The announcement came here at last week's international conference on autism, organized by Autisme et Troubles Envahissants du développement Montréal (ATEDM).
   McGill University epidemiologist emeritus Dr. Walter Spitzer and Dr. Victor Goldbloom, a pediatrician, former Quebec government minister and now president of ATEDM, told a news conference at the meeting they had become highly concerned over the past two years about what they call the "epidemic" of autism.
   They spoke about the possible association between the increase in the condition and live vaccines, particularly the trivalent mumps, measles and rubella (MMR).
   Dr. Goldbloom said the increases in the incidence of autism in the U.S. and the U.K. appear to work with the introduction of the MMR vaccine given to babies and young children as public health policy.
   Dr. Goldbloom said at the height of his practice as a pediatrician during the 1950s and 1960s, autism was a very rare condition. Until he joined the association two years ago, he had been unaware of the recent tenfold increase and believes few physicians realize the extent of the problem.
   The incidence in Quebec is now at least one in 300, compared to a rate 20 years ago of one in 10,000. The most recent figures from the U.S. Centres for Disease Control and Prevention show a rate as high as one in 150 for boys.
   Dr. Walter Spitzer said he sees autism as "a terminal disease, almost like a death" but which the families cannot mourn.
   "Autistic persons are prisoners for life," he said.
   Dr. Spitzer, who describes himself as a "worried agnostic," said he was initially skeptical of the suggested autism-vaccine link. But after reviewing the literature on behalf of 2,000 children in England, he could not set aside the possibility of a relationship.
   "After two years of study, I cannot ignore that one of the causes could be the triple vaccine. We need to be able to confirm that one way or the other. The manufacturers have never done safety studies."
   He planned the multinational study after reviewing findings presented by Dr. Andrew Wakefield, director of the inflammatory bowel disease study group of the Royal Free Hospital and University College medical school in London.
   "I reformatted those findings in the way an epidemiologist would present them.
   "I was startled by the fact that when you take autistic children and their reference points and look at the presence of rna mark measles viruses in their gut, the odds ratio is extraordinary."
   The ratio was 336 for autism and measles virus.
   "Dr. Wakefield and I looked at the numbers again, eliminated some biases and corrected," he said. "The odds ratio was down to 92."
   By comparison, for smoking and lung cancer, the odds ratio is 23, he said. And in a study he did of beta-agonists and asthma in children in Saskatchewan and Quebec, there was a very high odds ratio of 45.
   "The studies done so far were simply prevalence studies," said Dr. Spitzer. The important thing about the new multinational study is that it will be an incidence study.
   He said he and his colleagues are working pro bono on the study until an expected $17 million in funding is approved—likely by a consortium of the U.S. National Institutes of Health, the medical research councils of Canada and the U.K., the national research board in Germany and counterparts in Sweden and Denmark.
   The association/etiology study will span nine countries, including Canada, the U.S., the U.K., France, Poland, Argentina, Brazil, Denmark and Sweden. Co-ordination will be done in Montreal at McGill University's pharmacoepidemiology unit.
   The epidemiologists will look at 3,500 recently diagnosed children and examine their histories. They will be compared with a control group of 7,000 children.
   The study will take five years—four years of study and one year of analysis, said Dr. Spitzer.
   "The study will be serious, objective and scientifically rigorous," he added.
   Dr. Spitzer stressed the study was not and should not be seen as part of a crusade against vaccination.
   "I strongly believe in immunization in general," he said.
   "In the history of public health, it is the pillar of sound preventive practice and should be defended."
   But the way to defend the immunization principle was to look carefully at any suspect product. There was a question mark over the safety of the MMR and this could not be proved or disproved until, he said.
   Dr. Spitzer added he has no sponsorship from companies, governments or parents' associations for the new study.
   "I am doing this as my social responsibility to the children and their families. I don't accuse anyone. It is simply my public duty as a scientist," he said.