Reasonable Rascal
06-28-02, 13:04
CENTER FOR DEFENSE INFORMATION
http://www.cdi.org/terrorism/
June 26, 2002
It is not hard to understand why people fear smallpox. It is particularly frightening because it spreads rapidly and is essentially untreatable. The major form of it kills about one out of every three unvaccinated people who become infected, and often leaves survivors severely scarred. There is no known cure, although vaccination within the first few days of exposure can halt its progression or lessen the severity of symptoms.
But understanding U.S. smallpox vaccine policy is a different matter. On June 20, the 15-member federal Advisory Committee on Immunization Practices (ACIP) released its updated recommendations for use of smallpox vaccine to protect persons working with orthopoxviruses, to prepare for a possible bio-terrorism attack and respond to an attack involving smallpox.
The committee found that "under current circumstances, with no confirmed smallpox, and the risk of an attack assessed as low, vaccination of the general population is not recommended, as the potential benefits of vaccination do not outweigh the risks of vaccine complications." Instead, it advocated continuation of the 'ring' vaccination strategy, i.e., isolating smallpox patients and vaccinating everyone with whom they might have come into contact, thus creating a ring of immunized people around each outbreak, and preventing the virus from infecting new hosts. But it did recommend smallpox vaccine shots for "persons designated to respond or care for a suspected or confirmed case of smallpox," i.e., first responders.
The 'ring' strategy assumes the vaccine will be taken within four days after exposure. Although this strategy is appropriate to countering natural, relatively contained smallpox outbreaks, some experts oppose it as a counterterrorism approach, saying it would be insufficient for a deliberate attack on the large, mobile U.S. population. In past outbreaks, the average smallpox patient infected five other people. A recent study by the CATO Institute found the strategy "woefully inadequate."
There are no plans to carry out mass vaccinations, mostly because health officials worry about unnecessarily exposing people to risk of crippling or fatal side effects. For example, a vaccination may endanger people with compromised immune systems, like AIDS patients, or people undergoing radiation therapy for cancer.
The crux of the debate is whether the theoretical risk of an attack justifies the known risks of vaccination. The vaccine is made of live vaccinia virus (a virus similar to the variola virus, which causes smallpox). Live vaccinia can trigger rare but serious reactions, including encephalitis (an inflammation of the brain), systemic vaccinia infection, and extensive skin reactions. When vaccination was routine, vaccination deaths occurred every year.
Because of the high number of adverse reactions to the current vaccine, on Sept. 20, 2000, the Centers for Disease Control and Prevention (CDC) entered into an agreement with OraVax (Cambridge, Mass.) to produce a new smallpox vaccine.
Even before the anthrax attacks last fall, which heightened concern about possible future bio-terrorist attacks, the Department of Health and Human Services (HHS) began to increase public health preparedness through expansion of the existing stockpile of vaccine. The United States stopped producing smallpox vaccine in 1983.
The HHS contracted with the British-based Acambis PLC for purchase of 209 million doses of smallpox vaccine by the end of 2002. This will supplement the 15 million doses of vaccine currently available in the stockpile. It is also possible that the stockpile can be increased through dilution. A report in the April 25, 2002, New England Journal of Medicine indicates that our vaccine supply could be diluted 5-10 times and still retain its potency. Thus, the current stockpile represents up to 150 million doses.
In addition, Aventis Pasteur, a French vaccine maker, has agreed to make available to the United States more than 86 million doses of vaccine made in its factories more than 40 years ago. Vanderbilt University scientists are currently testing its viability. According to the HHS, by year's end America will have at least 286 million doses of vaccine. The National Institute of Allergy and Infectious Diseases compared the immune response prompted by three different vaccine strengths in previously unvaccinated volunteers and found no significant differences among the various dosages. The figure could be as high as 711 million doses, depending on how well the Aventis vaccine can be diluted. Depending on the estimates, these quantities should be sufficient to vaccinate most Americans.
There is no doubt that the American public is vulnerable to smallpox, assuming terrorists have access to it. This is because routine vaccination of civilians in the United Sates stopped in 1972 and in other parts of the world by 1984 at the latest. Because the protective immunity induced by the vaccine lasted only about 7-10 years, it has long since waned for those vaccinated as children, and millions more had never been vaccinated.
Indeed, doctors are poorly informed about the dangerous side effects of the smallpox vaccine and the U.S. government's plan to control an outbreak. A recent survey commissioned by the Centers for Disease Control and Prevention found that young doctors in particular - those too young to remember the last human case of smallpox - have relatively little knowledge of the disease. Most doctors interviewed in the survey at first were unfamiliar with this 'ring' vaccination strategy, which goes against medical logic of preemptively vaccinating many people.
Another option is voluntary vaccination. Even if only part of the population were vaccinated, it could greatly lessen the impact of any smallpox attack. The United States' stockpiled vaccine should be made available to the public. Even if only a small fraction of the population were vaccinated, a community immunity effect, which would lower the rate of transmission of a disease as well as significantly increase the chances of success of a ring containment strategy, would be produced. As a result, the chances of a successful attack would be lowered, and that could have a deterrent effect and might even prevent such an
attack.
Mass vaccination seems even more prudent in light of a newly published report from the Monterey Institute of International Studies. New information about an apparent accident in the former Soviet Union's biological weapons testing program three decades ago raises troubling questions about our own nation's ability to protect its citizens against a potential terrorist attack. The open-air test of a Soviet smallpox weapon in 1971 caused a small outbreak of the disease in a port on the Aral Sea, in what is now Kazakhstan, even among people who had been vaccinated.
The report concludes that the outbreak was triggered by airborne viruses from a germ warfare test on an island in the Aral Sea. If true, it raises the worrisome possibility that a smallpox attack might be carried out with plumes of germs that could infect large numbers of people simultaneously, instead of disseminating it among a target population via infected individuals, and thus making ring vaccination even less effective.
Sources:
Advisory Committee on Immunization Practices (ACIP), Use of Smallpox (Vaccinia) Vaccine, June 2002, http://www.cdc.gov/nip/smallpox/supp_recs.htm
CATO Policy Analysis: "Responding to the Threat of Smallpox Bioterrorism: An Ounce of Prevention Is Best Approach," http://www.cato.org/pubs/pas/pa434.pdf
CNS Occasional Paper No. 9, The 1971 Smallpox Epidemic in Aralsk, Kazakhstan, and the Soviet Biological Warfare Program; http://cns.miis.edu/pubs/opapers/op9/op9.pdf
http://www.cdi.org/terrorism/
June 26, 2002
It is not hard to understand why people fear smallpox. It is particularly frightening because it spreads rapidly and is essentially untreatable. The major form of it kills about one out of every three unvaccinated people who become infected, and often leaves survivors severely scarred. There is no known cure, although vaccination within the first few days of exposure can halt its progression or lessen the severity of symptoms.
But understanding U.S. smallpox vaccine policy is a different matter. On June 20, the 15-member federal Advisory Committee on Immunization Practices (ACIP) released its updated recommendations for use of smallpox vaccine to protect persons working with orthopoxviruses, to prepare for a possible bio-terrorism attack and respond to an attack involving smallpox.
The committee found that "under current circumstances, with no confirmed smallpox, and the risk of an attack assessed as low, vaccination of the general population is not recommended, as the potential benefits of vaccination do not outweigh the risks of vaccine complications." Instead, it advocated continuation of the 'ring' vaccination strategy, i.e., isolating smallpox patients and vaccinating everyone with whom they might have come into contact, thus creating a ring of immunized people around each outbreak, and preventing the virus from infecting new hosts. But it did recommend smallpox vaccine shots for "persons designated to respond or care for a suspected or confirmed case of smallpox," i.e., first responders.
The 'ring' strategy assumes the vaccine will be taken within four days after exposure. Although this strategy is appropriate to countering natural, relatively contained smallpox outbreaks, some experts oppose it as a counterterrorism approach, saying it would be insufficient for a deliberate attack on the large, mobile U.S. population. In past outbreaks, the average smallpox patient infected five other people. A recent study by the CATO Institute found the strategy "woefully inadequate."
There are no plans to carry out mass vaccinations, mostly because health officials worry about unnecessarily exposing people to risk of crippling or fatal side effects. For example, a vaccination may endanger people with compromised immune systems, like AIDS patients, or people undergoing radiation therapy for cancer.
The crux of the debate is whether the theoretical risk of an attack justifies the known risks of vaccination. The vaccine is made of live vaccinia virus (a virus similar to the variola virus, which causes smallpox). Live vaccinia can trigger rare but serious reactions, including encephalitis (an inflammation of the brain), systemic vaccinia infection, and extensive skin reactions. When vaccination was routine, vaccination deaths occurred every year.
Because of the high number of adverse reactions to the current vaccine, on Sept. 20, 2000, the Centers for Disease Control and Prevention (CDC) entered into an agreement with OraVax (Cambridge, Mass.) to produce a new smallpox vaccine.
Even before the anthrax attacks last fall, which heightened concern about possible future bio-terrorist attacks, the Department of Health and Human Services (HHS) began to increase public health preparedness through expansion of the existing stockpile of vaccine. The United States stopped producing smallpox vaccine in 1983.
The HHS contracted with the British-based Acambis PLC for purchase of 209 million doses of smallpox vaccine by the end of 2002. This will supplement the 15 million doses of vaccine currently available in the stockpile. It is also possible that the stockpile can be increased through dilution. A report in the April 25, 2002, New England Journal of Medicine indicates that our vaccine supply could be diluted 5-10 times and still retain its potency. Thus, the current stockpile represents up to 150 million doses.
In addition, Aventis Pasteur, a French vaccine maker, has agreed to make available to the United States more than 86 million doses of vaccine made in its factories more than 40 years ago. Vanderbilt University scientists are currently testing its viability. According to the HHS, by year's end America will have at least 286 million doses of vaccine. The National Institute of Allergy and Infectious Diseases compared the immune response prompted by three different vaccine strengths in previously unvaccinated volunteers and found no significant differences among the various dosages. The figure could be as high as 711 million doses, depending on how well the Aventis vaccine can be diluted. Depending on the estimates, these quantities should be sufficient to vaccinate most Americans.
There is no doubt that the American public is vulnerable to smallpox, assuming terrorists have access to it. This is because routine vaccination of civilians in the United Sates stopped in 1972 and in other parts of the world by 1984 at the latest. Because the protective immunity induced by the vaccine lasted only about 7-10 years, it has long since waned for those vaccinated as children, and millions more had never been vaccinated.
Indeed, doctors are poorly informed about the dangerous side effects of the smallpox vaccine and the U.S. government's plan to control an outbreak. A recent survey commissioned by the Centers for Disease Control and Prevention found that young doctors in particular - those too young to remember the last human case of smallpox - have relatively little knowledge of the disease. Most doctors interviewed in the survey at first were unfamiliar with this 'ring' vaccination strategy, which goes against medical logic of preemptively vaccinating many people.
Another option is voluntary vaccination. Even if only part of the population were vaccinated, it could greatly lessen the impact of any smallpox attack. The United States' stockpiled vaccine should be made available to the public. Even if only a small fraction of the population were vaccinated, a community immunity effect, which would lower the rate of transmission of a disease as well as significantly increase the chances of success of a ring containment strategy, would be produced. As a result, the chances of a successful attack would be lowered, and that could have a deterrent effect and might even prevent such an
attack.
Mass vaccination seems even more prudent in light of a newly published report from the Monterey Institute of International Studies. New information about an apparent accident in the former Soviet Union's biological weapons testing program three decades ago raises troubling questions about our own nation's ability to protect its citizens against a potential terrorist attack. The open-air test of a Soviet smallpox weapon in 1971 caused a small outbreak of the disease in a port on the Aral Sea, in what is now Kazakhstan, even among people who had been vaccinated.
The report concludes that the outbreak was triggered by airborne viruses from a germ warfare test on an island in the Aral Sea. If true, it raises the worrisome possibility that a smallpox attack might be carried out with plumes of germs that could infect large numbers of people simultaneously, instead of disseminating it among a target population via infected individuals, and thus making ring vaccination even less effective.
Sources:
Advisory Committee on Immunization Practices (ACIP), Use of Smallpox (Vaccinia) Vaccine, June 2002, http://www.cdc.gov/nip/smallpox/supp_recs.htm
CATO Policy Analysis: "Responding to the Threat of Smallpox Bioterrorism: An Ounce of Prevention Is Best Approach," http://www.cato.org/pubs/pas/pa434.pdf
CNS Occasional Paper No. 9, The 1971 Smallpox Epidemic in Aralsk, Kazakhstan, and the Soviet Biological Warfare Program; http://cns.miis.edu/pubs/opapers/op9/op9.pdf