read on:But for Kennedy to be right, a growing consensus in the medical establishment had to be wrong. Indeed, Kennedy blasted a leading organ of science that had just vindicated both the MMR vaccine and thimerosal, the Institute of Medicine (IOM). “The CDC [Centers for Disease Control and Prevention] paid the Institute of Medicine to conduct a new study to whitewash the risks of thimerosal,” Kennedy wrote, “ordering researchers to ‘rule out’ the chemical’s link to autism.” In reality, the IOM—a branch of the National Academy of Sciences (NAS), the government’s top independent scientific adviser—carefully creates firewalls between the funding it receives to conduct scientific assessments and the results it ultimately produces. “Funders don’t control the composition of the committee, and they don’t meet with the committee,” says Harvard public-health researcher Marie McCormick, who chaired the IOM vaccine-safety committee in question. “And on no NAS or IOM committee are the members paid; they all work pro bono. There’s no reason for them not to look at the data.” The same year Kennedy’s article came out, journalist David Kirby published Evidence of Harm—Mercury in Vaccines and the Autism Epidemic: A Medical Controversy. He followed a group of parents from the Coalition for SafeMinds, an autism activist organization. They had grown convinced that vaccines and other environmental factors had caused their children’s conditions. Kirby’s chronicle of the parents’ efforts to publicize the dangers of vaccines became a best seller and greatly advanced SafeMinds’ cause. Yet even as vaccine hysteria reached a fever pitch in the wake of Kennedy’s and Kirby’s writings, the scientific evidence was leaning strongly in the other direction. In discounting the dangers of both the MMR vaccine and thimerosal, the IOM had multiple large epidemiological studies to rely on. For MMR, the IOM examined 16 studies. All but two, which were dismissed because of “serious methodological flaws,” showed no evidence of a link. For thimerosal, the IOM looked at five studies, examining populations in Sweden, Denmark, the United Kingdom, and the United States (studies that vaccine critics contend were flawed). Since then, further research has strengthened and vindicated the committee’s original conclusion. It is a conclusion that has been “independently reached by scientific and professional committees around the world,” as a recent science journal commentary noted. Either the scientific community has found a clear, reassuring answer to the questions raised about thimerosal in vaccines, or there is a global scientific conspiracy to bury the truth. Whether the public is hearing the scientific community’s answer is another matter. “It’s not hard to scare people,” says pediatrician and leading vaccine advocate Paul Offit, who himself coinvented a vaccine. “But it’s extremely difficult to unscare them.” A backlash against vaccine skeptics is beginning to mount. Standing up to fellow celebrities, actress Amanda Peet, who recently vaccinated her baby daughter, has become a spokeswoman for the pro-vaccine group Every Child by Two. Offit’s book Autism’s False Prophets has further galvanized vaccine defenders—not only by debunking the science of those who claim vaccines are dangerous but also by contending that the parents of autistic children and the children themselves are indeed victims, not of vaccines but of medical misinformation. The provaccine case starts with some undeniable facts: Vaccines are, as the IOM puts it, “one of the greatest achievements of public health.” The CDC estimates that thanks to vaccines, we have reduced morbidity by 99 percent or more for smallpox, diphtheria, measles, polio, and rubella. Averaged over the course of the 20th century, these five diseases killed nearly 650,000 people annually. They now kill fewer than 100. That is not to say vaccines are perfectly safe; in rare cases they can cause serious, well-known adverse side effects. But what researchers consider unequivocally unsafe is to avoid them. As scientists at the Johns Hopkins Bloomberg School of Public Health recently found while investigating whooping cough outbreaks in and around Michigan, “geographic pockets of vaccine exemptors pose a risk to the whole community.” When it comes to autism, vaccine defenders make two central claims. First, the condition is likely to be mostly genetic rather than environmentally caused; and second, there are reasons to doubt whether there is really a rising autism epidemic at all. It is misleading to think of autism as a single disorder. Rather, it is a spectrum of disorders showing great variability in symptoms and expression but fundamentally characterized by failed social development, inability to communicate, and obsessive repetitive behavior. Autism generally appears in children at early ages, sometimes suddenly, and its genetic component has long been recognized. Studies have shown that if one identical twin has autism, there is at least a 60 percent chance that the other also does. “From my point of view, it’s a condition associated with genetic defects and developmental biology problems,” says Peter Hotez, a George Washington University microbiologist and father of an autistic child. Hotez, who is also president of the Sabin Vaccine Institute, says, “I don’t think it’s possible to explain on the basis of any vaccine toxin that is acquired after the baby is born.” Still, scientists cannot fully rule out environmental triggers—including various types of toxicity—that might interact with a given individual’s preexisting genetic inclination. Autism is a complex disorder with multiple forms of expression and potentially multiple types of causation that are incompletely understood. As for whether autism is rising, a number of experts say it is hard to know. Is the increase real, or is it largely the result of more attention to the condition, an expansion of the autism spectrum to embrace many different heterogeneous disorders, a new focus on children classified as autistic in federal special education programs during the 1990s, and other factors? It could be some combination of all these things. But if environmental triggers of autism cannot be ruled out, the idea that those triggers can be found in the MMR vaccine or in thimerosal has crumbled under the weight of scientific refutation. Epidemiological studies have cast grave doubt on Andrew Wakefield’s MMR hypothesis—and so have subsequent scandals. Nearly all of Wakefield’s coauthors have since retracted the autism implications of their work; The Lancet has also backed away from the study. A series of investigative stories published in The Times of London unearthed Wakefield’s undisclosed ties to vaccine litigation in the U.K. and, more recently, suggested he fabricated his data (which Wakefield denies).
Posted on: Wed, 13 Aug 2014 20:11:07 +0000
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