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Book Review Summer 2005
Evidence of Harm Yes, they are all here. The profound mystery of the autistic children, the misery and despair of their parents, the passion and obsession of the activist groups, the scientists hiding behind their jargon and institutional prerogatives, the politicians seeking to do right but constrained by the lobbyists and their dependence on big pharmaceutical clients, the media, the pediatricians, the federal drug regulation bureaucracy: all have been caught up in the amazing epidemic of autism during the past two decades. The urge to blame something and someone is human, and the proponents have seized upon mercury as the chief villain. Yet, after 400 plus pages in this book, are we any smarter about the cause and cure of this devastating disorder? Not unexpectedly, the answer is yes and no. Clearly autism has a genetic component; it often runs in families. But this cannot explain the enormous increase in the disorder, from 1 in 10,000 births back in the 1960s to an estimated 1 in 167 currently. Classic autism, first described in the 1940s, consists of impaired language function, poor communication abilities, and repetitive, often meaningless behavior. It is often accompanied by certain physical features and gastrointestinal problems. Onset is usually in the 1-3 year old age group. It is a lifelong disorder that seriously impairs the victim's ability to function in society and usually demands an enormous emotional and financial outlay for parents. Treatments including psychotropic drugs, vitamin and behavioral modification therapy have had only anecdotal success and many alternative and unproven remedies have been hawked by the inevitable quackery that surrounds diseases without established cures. The quest for a cause has been elusive, though there has been no lack of proposals. Once cold and unfeeling "refrigerator mothers" were blamed. Now the leading concept is some environmental toxin that interacts with a genetically susceptible, immune immature infant...either in utero or in the first several years of life. Since animal experiments are limited and prospective studies on young, healthy children are ethically impossible, epidemiologic analysis been the chief mechanism for studying the cause of the disorder to date. But environmental and epidemiologic data, though often useful, are subject to numerous confounding factors and often, a wide variety of differing interpretations and reinterpretations. The repeated efforts of the parental groups to obtain raw data from the CDC's study of autism in three HMOs (the so-called VSD study) using the Freedom of Information Act and the official excuses and stonewalling is well chronicled in the book and does generate suspicion of collusion or cover-up. Mr. Kirby's book recounts the history and evidence for the association between mercury and autism or pervasive development disorder, (PDD/NOS) in the expansive parlance of the American Psychiatric Association. We are not necessarily talking about elemental mercury, an admittedly nasty substance, but organic mercury, specifically the ethyl mercury contained in thimerosal, a preservative in many childhood vaccines. Once known as Mercurochrome or Merthiolate, it was a common antiseptic in the family medicine chest of the 1940s and 50s. It was withdrawn from the over-the-counter market because of a concern that it caused cell injury. However, it has been used as an antibacterial agent in multi-dose vaccine vials since the 1930s. Only recently, under pressure from parents groups (the so-called mercury moms) and Congress (largely spearheaded by Representative Dan Burton, Republican from Indiana who has an autistic grandchild) have the vaccine manufacturers begun to provide thimerosal-free vaccines. Some such as influenza vaccine, recommended by American Academy of Pediatrics for children 6-24 months, still contain the preservative as does the Rh0(D) immune globulin given to pregnant Rh negative women. In California and Iowa, state legislatures have recently precluded the use of the preservative in children's vaccines. The battle sometimes takes on the tone of a medieval witch hunt with accusations of conspiracy and deliberate fraud by all who question the CANs and DANs and the other activist organizations that are committed to the mercury toxicity hypothesis. Many medical, legal and other professionals with autistic children have been recruited, often leading to serious presentations by the "mercury mafia" at scientific meetings and government investigative hearings. The CDC and FDA have been the major targets as responsible parties for allowing the use of thimerosal, presumably under pressure, if not control, by the vaccine manufacturers. Needless to say, the plaintiffs' bar has been circling like vultures over the various claims, hearings and agency reports. Unfortunately for them, a two paragraph rider attached to the massive Homeland Security Act of 2002 was passed by the Congress, dismissing hundreds of lawsuits against the vaccine manufacturers, shunting them to the federal "vaccine court" where the manufacturers are protected and claims are paid out of taxpayer funds. The major protagonist in Mr. Kirby's book is Lyn Redwood, suburban Atlanta nurse with her physician husband Tom. She, like so many other parents of these unfortunate children, noticed the onset of symptoms in her son Will shortly after he received multiple vaccinations. Autistic behavior typically becomes apparent in the 18-36 month period, just during and after the bulk of childhood vaccinations. Boys outnumber girls, 4:1. In the 1990s most of the attention was focused on MMR (measles, mumps, rubella vaccine which does not contain thimerosal), largely based on studies by a British researcher, now generally debunked by the scientific establishment. The attention has shifted to the mercury-containing preservative. There is little doubt that inorganic mercury and perhaps the methyl mercury found in certain fish are potential neurotoxins. The story for the ethyl mercury in thimerosal remains cloudy: some claim it is too large a molecule to get past the anatomic blood-brain barrier while others show evidence for metabolism to inorganic mercury which can pass the barrier as well as the placenta. Many other players have been researched and get considerable space in the book: parents, doctors, lawyers, business executives, politicians, scientists. The professional credentials of many of the parents in the activist organizations lend an air of authority to their claims. Will thimerosal turn out to be like thalidomide that caused such serious birth defects (phycomelia) in the 1960s or like Bendectin, the drug for morning sickness in pregnancy that was falsely accused of causing birth defects (Daubert v. Merrell Dow supreme court decision)? Like thimerosal, both associations depended on epidemiologic evidence that is often hard to interpret because so many additional factors may be in play. When evidence is contradictory, it is a case of which set of battling experts with divergent opinions is most credible or has the biggest public megaphone. So many of the self-taught “autism experts” have family members who are afflicted, their zeal is understandable but their objectivity may be compromised. There is a human need to blame something or someone for bad events that have no immediately obvious explanation. Similarly, distrust of big pharmaceutical companies and government agencies is widespread, often with justification. Conflicts of interest and conspiracy theories abound. Cumulative doses of mercury such as those given in the increasing number of vaccinations for children exceed EPA limits for mercury exposure. Large single doses may be more detrimental than slow, chronic dosing such as eating tuna or swordfish. Hair analysis and chelation treatments have demonstrated large amounts of mercury in many affected children but are of uncertain clinical or research value. Each side has differing interpretations. The public health community has a vested interest in their basic concepts, according to Safe Minds, an umbrella group that has taken the lead in the pursuit of thimerosal-containing vaccines. To admit that vaccines can cause harm and that this harm could have been prevented is anathema to the basic credo of medicine (primum nolo nocere) and to the mind set of the scientific community responsible for the public's health. Look at all the good vaccines have done in ridding the population of serious and lethal diseases. Similarly, the parental groups and their scientific supporters have no recourse to causation, legally or medically, if the disease is purely genetic and the recent explosion of cases is a result of better diagnosis and general awareness of autistic spectrum disorders. The urge to be compensated in some fashion for serious injury or unfortunate events is based in human nature and in tort law. In May 2004 the Institute of Medicine issued a statement that "the bulk of evidence favors rejection of a causal relationship" between thimerosal and autism. But as Kirby rightly points out, "no evidence of harm" is not the same as proof of safety. In many ways the anti-thimerosal campaign has been victorious. The preservative has been removed from most if not all childhood vaccines and the ongoing battle has raised the profile of this enigmatic affliction to major public attention and to increasing scientific investigation. One should expect a diminution in the incidence of autism in the near future if thimerosal is truly responsible. Meanwhile, the Kirby book gives an up-to-date and accurate, if not always fair and balanced view of the battle. |
