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Tuesday, June 04, 2002The first article is about the search for a safer vaccine. It opens with the description by Dr. James Koopman of a complication of the vaccine in a small child in India: "James Koopman saw the last 16 cases of smallpox in the Indian district of Azhagar in the early 1970s, but by now they blur together. Crystal clear, however, is the memory of a child, about 1 year old, who suffered from an uncontrollable infection called progressive vaccinia after receiving a smallpox vaccination in 1973. "It completely destroyed her arm, right down to the bone," says Koopman, now a researcher at the University of Michigan, Ann Arbor." He is describing progressive vaccinia, a complication of the vaccine that can be fatal. It occurs at a rate of 1 to 2 per one million first time recipients of the vaccine, and 6 to 7 per one million repeat vaccine recipients. It occurs most frequently in children with cellular immune deficiencies, a condition that is not necessarily easily recognized or diagnosed. This is a very real and possible side effect, and one that must be weighed in the decision whether or not to undergo vaccination. "Vaccinia--known in the United States as a Wyeth product called Dryvax--works by producing a local infection on the arm, a so-called take, which normally heals in 2 to 3 weeks. But in progressive vaccinia, it grows out of control. Other serious side effects include eczema vaccinatum, a localized or systemic infection in people with a history of eczema, and encephalitis, a brain inflammation. During the smallpox eradication era, about 1250 in every million vaccinees--many of them children under 2 years of age--suffered one of these side effects, and about one in a million died. Researchers expect that those numbers would be significantly higher today, as millions of people have compromised immune systems as a result of HIV or immunosuppressive drugs. Eczema rates have also shot up, for unknown reasons." Encephalitis happens in roughly 12 out of one million people who are vaccinated for the first time, and in two out of one million who are vaccinated for a second time. Progressive vaccinia occurs at a rate of 1 to 2 per one million first time recipients of the vaccine, and 6 to 7 per one million repeat vaccine recipients. Eczema vaccinatum happens in 122 per million first time recipients of the vaccine and in 6 per million second time recipients. That means that the total of potentially fatal complications was at the most in 149 per million vaccine recipients, not, as this story suggests the enormous 1,250 per million recipients. The reporter has magnifed the side effect incidence by nearly a factor of ten. It was an honest mistake, he just failed to read the footnotes to the table from the issue of the Morbidity and Mortality Weekly Reports that these figures came from. The figure of 1,250 side effects per million vaccine recipients includes all side effects, including those which are common but not fatal, such as local reactions to the vaccine and secondary bacterial infections at the site of vaccination. (Click here to see the table yourself and compare the figures with the report. Scroll down to Table 3.) And yes, it's true that there are more people these days with compromised immune systems, but they would not be getting the vaccine. It is contraindicated in those situations. The article went on to speak glowingly of the research efforts being put into a safer vaccine. There was one voice, however, who expressed doubts about the new vaccine's effectiveness (it's never been tested in people or in a time of contagion): "But others are not so sure. Donald A. Henderson, former head of the World Health Organization's eradication effort and now a top bioterrorism adviser to the Department of Health and Human Services, for instance, says he'd be leery of relying on anything less than the tried and true to protect the population. "I don't know how you could ever be completely sure of [MVA's] efficacy," Henderson says." I would listen to him. He's our leading expert on smallpox. He saw just what it can do, even in communities with high levels of immunity. The second article, entitled How Devastating Would a Smallpox Attack Really Be? relied even more on the optimists among the experts: "Smallpox is a barely contagious and very slow-spreading infection," says James Koopman of the University of Michigan, Ann Arbor, who helped fight the disease in India in the early 1970s. Indeed, the way it spread in Dark Winter ( an exercise in bioterror preparedness held last summer by the government) was "silly," says Michael Lane, a former director of the smallpox eradication unit at the Centers for Disease Control and Prevention (CDC) in Atlanta. "There's no way that's going to happen." Oh, really? "Barely contagious and very slow-spreading?" Then why was it once called the "devouring monster?" Why does the US Army's Bluebook on Medical Management of Biological Casualties estimate that only 10 - 100 organisms, and on average only 12, are needed to transmit an infection? (download the chapter on bioweapon agent characteristics for the chart.) I'll put my money on the US Army estimates over some academic in Ann Arbor. The Army is known for being practical and realistic when it comes to practicing medicine. Academics aren't. "Already, in briefings for state and local officials, CDC's senior adviser for smallpox preparedness and response, Harold Margolis, is trying to "demystify" smallpox. "We know this disease," says Margolis. "We have eradicated it once, and we can do it again." Yes, Dr. Margolis, you did eradicate it once. But that was after 150 years of worldwide vaccination efforts mixed with naturally acquired immunity from infection. There were record levels of immunity around the world back then, which made your task much easier. We no longer live in that same world, and your task will be much harder and come at a much higher price this time around. You are coming across as a little too cocky for our own good. "For instance, these outbreaks took place in winter, the season terrorists would choose because it's peak transmission time for smallpox; infected people had lots of interaction with others; and doctors were slow to recognize the disease, as they would likely be today. (He's referring to "Dark Winter" an exercise in bioterror preparedness that the government did last summer.) They settled on an R 0 of 10--although they think that may be on the low side. (The R0 refers to the number of people an infected person would give the disease to.) In one famous and "particularly instructive" case, they wrote in a paper, a patient who returned to Yugoslavia from a trip to Iraq in 1972 infected 11 others, who in turn caused 140 "second generation" cases. The same number--10--had also been suggested in several papers (including one in Science, 26 February 1999, p. 1279) by the former head of the smallpox eradication effort, Donald A. Henderson, who served as a consultant to Dark Winter. But a team led by CDC's Martin Meltzer, which published a smallpox outbreak model in Emerging Infectious Diseases last fall, concluded after a similar analysis of many more past outbreaks that the average rate of transmission was lower than 2. The CDC group recognized that today's citizens might be more vulnerable but not all that much more, so they ran scenarios in which R 0 was 2, 3, or 5, resulting in outbreaks that were easier to contain than the one in Dark Winter. Raymond Gani and Steve Leach of the Centre for Applied Microbiology and Research in Porton Down, U.K., reached a conclusion somewhere in the middle after analyzing historic outbreaks. R 0 was usually somewhere between 3.5 and 6, they wrote in Nature last December. In reality, says Koopman, the transmission rate may be much lower than past publications suggest. The published literature contains a skewed record, he says, tending to register significant outbreaks, whereas small ones were never written up. Koopman puts smallpox's R 0 at "barely above 1." If true, a small attack may well fizzle after a handful of additional cases." In other words, the CDC is just guessing. They're ignoring evidence from our foremost smallpox expert, D.A. Henderson, that the disease is highly communicable, and downsizing the degree of communicability based on a time in history when background immunity was at an all-time high. At the same time, there is no way of knowing which form of smallpox was responsible for the outbreaks they are including in their studies: Variola minor which is less devastating and less communicable, or Variola major which is very contagious and has a thirty percent mortality rate. This is very reckless of them. They cannot assume the same numbers today, after thirty years of no natural smallpox in the world. And we can assume that any bioterror weapon is going to use the more dangerous Variola major. We are a particularly vulnerable population. And this Dr. Koopman, my goodness, he must have slept through his history lessons to think that one infected person only infects one other person, and that a "small attack may well fizzle after a handful of additional cases." Has he never read about the conquest of Central and South America and the role smallpox played in the European victory? "Again, past experience suggests that the risks are much smaller than most people would think. Most smallpox infections were the result of several hours spent in close contact--usually 2 meters or less--to a patient, says Lane. Indeed, Koopman says some patients did not infect anybody at all. "In India, we got very worried sometimes, because a patient had gone into a big crowd, or boarded a bus--and yet there was no secondary transmission," he says." Again with this Dr. Koopman. He's basing all of his conclusions on his experience in India. Has he never entertained the thought that no one on that bus caught smallpox because they were all immune already? Let me tell you something. I attended a lecture by D.A. Henderson on smallpox before September 11, and he didn't pull any punches about just how contagious this disease is. He showed us a map of a hospital that housed a smallpox patient and where each of the subsequent victims were in relation to the quarantined patient's room. Some of them were on the same floor, some of them were on completely separate floors with no direct contact, and one man caught it simply by opening the door to the hallway that had the patient's room in it and asking for directions. That is how contagious the disease can be. It's frustrating to listen to these people play up the risks of the vaccine, which are very real, but play down the risks of the disease. We would all be much better off if they were honest about both. That's why I don't think it's in our best interest to have some committee from the CDC decide whether or not we can be vaccinated. It would be much better for all of us if they just gave us the choice, and the right facts. CORRECTION: I made a mistake in the calculation of the total number of potentially fatal side effects from the smallpox vaccine. The number is 294 per million vaccine recipients, not 149 as I wrote. That means that the Science article overestimates the side effects by a factor of four, not ten. Sorry for the mistake. Forgive me. Mea culpa, mea culpa, mea maxima culpa. posted by Sydney on 6/04/2002 05:42:00 AM 0 comments 0 Comments: |
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