Vaccine Conference Exclusive Report - Page 9

Walter Spitzer, MD, is professor emeritus of epidemiology, McGill University, and clinical professor of medicine, Stanford University. He believes that, in the absence of clinical, social, religious, or other extenuating circumstances, children should be vaccinated for communicable diseases but questions whether prevention of measles, mumps, and rubella is best effected with multivalent MMR.

"What are we calling for?" he asked. "Objective, valid, reasonable, rigorous, research. I agree fully that we should be shown the science. In the rules of science, you cannot even think about going to origins of cause until you've established an association...."

"So how do you diagnose causation in the presence of observed association?" he asked.

Spitzer cited a blind study by Dr. Andrew Wakefield that compared 25 autistic children and 25 healthy children. The study found that 25 autistic children showed measles virus in their intestines, whereas the virus was only found in one of the healthy children's intestines.

"If you calculate, you get an odds ratio of 336 with that probability value. An odds ratio of 336 means, as the British say, the bug is in the gut. This gut-brain-autism thing, it isn't just speculation."

By comparison, Spitzer said, studies of the association of oral contraceptives and strokes revealed an odds ratio of between 4 and 9, and in studies of cigarette smoking and lung cancer the odds ratio was 23.

"I have not found any reports of any long-term control studies that bear on safety by...drug companies, regulators, or anyone who should be worried about what Dr. Wakefield's research might mean."

Referring to the most widely cited study that says that MMR is safe and has no link with autistic enterocolitis, Spitzer said that it was too short-term in its follow-up, representativeness wasn't demonstrated, date marks were inconsistent, the analysis was incorrect, and the study was uncontrolled and had conflicts of interest. "At best it is a hypothesis-generating study."

An epidemiologically sound study, Spitzer said, would include collaborations between governments, public health agencies, and consumer groups; it would be accountable to an international board that did not have any conflict of interests in the pharmaceutical companies, and would cost an estimated $57 million. "Many vaccine manufacturers have sold hundreds of millions of dollars worldwide and have not done or funded any controlled post-marketing epidemiology bearing on safety," he said.