Fall 2002 |
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Faculty Column |
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Risky Diseases, Risky Vaccines, Risky Policies Public concern is rising about risks of vaccination. By Ann Bostrom | |
In the late 1990s, health authorities worldwide considered destroying their remaining stocks of live smallpox virus – until they began to worry about bioterrorism.
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Immunization in the 20th century had eliminated smallpox, but not its menace. In its heyday, smallpox killed a third to more than one-half of its victims and nearly all infants in some outbreaks. Global travel and ever denser, susceptible populations made it plausible that smallpox, if released, could again become the "speckled monster."
In June 2002, the Advisory Committee on Immunization Practices (ACIP) recommended revisions to U.S. smallpox vaccination policy. Pushed by the Bush Administration, the ACIP made its recommendation months earlier than scheduled.
The ACIP proposed a ring-vaccination policy, along with early vaccination of health workers and emergency response personnel. Successfully used to complete the eradication of smallpox, ring vaccination controls outbreaks by vaccinating everyone who is likely to have been exposed to smallpox, creating a "ring of vaccinated people" around those infected.
Since the proposal in June, debate about smallpox vaccination has continued in the United States and elsewhere. In fact, the ACIP's invitation for public comment on its proposal (www.bt.cdc.gov/agent/smallpox) marked new territory. The culture of advocacy in public health has not always readily meshed with deliberative processes, nor with the uncertainties explicit in scientific standards of evidence.
The recommended childhood immunization schedule now includes more than three dozen doses of 11 different vaccines before the age of 12 – not counting the hepatitis A and influenza vaccinations recommended for some children.
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Though federal health officials released a revised "Smallpox Vaccination Clinic Guide and Response Plan" (for implementation of mass immunization after an eventual outbreak) in late September 2002, the government did not announce its vaccination policy until December, six months after the ACIP made its recommendations. The Bush Administration – which has ordered smallpox vaccinations for military personnel in high-risk areas and made them available to public healthcare workers and first responders – believes several countries have viable smallpox stocks and has reason to believe Iraq has a viable biological weapons program. In the 1980s, the United States supported Iraq covertly in its development of biological weapons, according to recent news articles in Newsweek, the Associated Press, The Guardian and The (London) Times.
Under Bush's smallpox vaccination policy, a very large number of people will be faced with the decision of whether to get what is widely acknowledged to be a risky vaccine. There will be some severe reactions (an estimated 15 per million), and likely even deaths, from the vaccine. Yet clauses in the new Homeland Security Act (HR 5710, e.g., Section 304) eliminate liability for vaccine manufacturers. Further, Section 304(B)(2)(d)(i) states, with regard to smallpox, that "The Secretary [of Homeland Security] may issue a declaration [...] concluding that an actual or potential bioterrorist incident or other actual or potential public health emergency makes advisable the administration of a covered countermeasure to a category or categories of individuals." This language appears deliberately ambiguous and raises the specter of mandatory vaccination.
To understand the current controversy, one must realize that the scientific and technological underpinnings for U.S. vaccination policy come from the Centers for Disease Control and Prevention (CDC) in Atlanta, other federal agencies, the Institute of Medicine and researchers around the world. Where there are uncertainties – and there are many – scientists continue to disagree, often regardless of the size of the risk. There are disagreements, for example, on the probabilities of complications from the smallpox vaccine, and on the risk from the disease because most exposure scenarios under consideration involve bio-terrorism. The biggest scientific players have developed their own models of disease transmission, with critical parameters that can differ by a factor of 10.
Consequently, there is scientific disagreement on the efficacy of ring vaccination policies for smallpox, too. Presumably, the ACIP believes the policy it recommended would protect public health effectively, at an acceptable risk and cost. In any such policy decision, public health, individual liberties and fairness must be weighed with the relevant science and technology, their uncertainties, and the practicalities of vaccine availability and administration.
Take the nation's childhood vaccination requirements as an example. Since 1980, at least 15 new or improved vaccines have become available, including the varicella (chickenpox) vaccine. The ACIP-recommended childhood immunization schedule now includes more than three-dozen doses of 11 different vaccines before the age of 12 – not counting the hepatitis A and influenza vaccinations recommended for some children.
Over time, consumer groups have demanded – and gotten – greater scrutiny of immunization practices and policies, and of the costs of limiting individual choices with mandatory immunization. Now, parental concerns about vaccine safety – while still low – appear to be creeping higher.
At its peak, the smallpox virus killed a third to more than one-half of its victims and nearly all infants in some outbreaks.
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In response, non-governmental vaccine advocacy organizations have also raised their voices. Among those groups are the Allied Vaccine Group
(www.vaccine.org), the National Immunization Network
(www.immunizationinfo.org/)
and the Children's Vaccine Program at the Program for Appropriate Technology in Health
(www.childrensvaccine.org).
This proliferation of vaccines and information may be contributing to vaccine safety concerns. Public health experts, such as Drs. Gene Gangerosa at Emory University and Bob Chen at the CDC, attribute increased concerns to a shift in personal risk-benefit calculations caused by the near-complete disappearance of some diseases. Thanks to immunization, we are unfamiliar with smallpox, polio, whooping cough, diphtheria and several other infectious diseases.
Although many childhood vaccines are now required for school entry by state laws, states allow medical, and sometimes religious or philosophical, exemptions. A small percentage of parents choose not to vaccinate their children because they fear that vaccines cause autism or other immune dysfunctions. In contrast, tests of smallpox vaccines in October 2001 were swamped with volunteers hoping to get the vaccine for themselves and their children.
To better address safety concerns, federal agencies have increased research on and attention to vaccine safety issues. Also, research on vaccine risks, risk perceptions and risk communication has been growing at Georgia Tech and elsewhere.
Meanwhile, physicians' opinions and recommendations often determine individuals' vaccination decisions, and those opinions presumably would also affect choices about a national voluntary smallpox vaccination program following an outbreak. By law, vaccine providers must communicate the risks and benefits of immunizations. This task has become daunting as vaccine policies and the immunization schedule have become more complex. One recent study found that adherence to chickenpox vaccine recommendations was increased by physicians' experience with encephalitis caused by chickenpox. However, adherence was decreased by physicians' perceptions that chickenpox is not very serious and that the vaccine is not medically cost-effective. In the CDC smallpox vaccine trial last fall, a survey of physicians revealed their alarm at and mistaken beliefs about normal smallpox vaccine reactions – fever, sore arms and lymph node swelling. Their reactions echo the previous study's finding that providers' perceptions of disease and vaccine risks are likely to affect vaccination practices.
Research on risk perceptions by Baruch Fischhoff of Carnegie Mellon University, Paul Slovic of Decision Research and many others shows that subjective risk assessments depend on context and specific risk characteristics – though not in the same way as scientific risk assessments do. In a study of subjective estimates of disease and vaccine risks, I and my colleagues at the CDC and the University of Alberta have preliminary findings that suggest providing even a few actual risk frequencies can influence a person's perceived risk. But reliable numbers can be hard to establish, as disagreements about the risks of smallpox illustrate.
Risk perceptions of parents, physicians and policymakers influence vaccine decisions and policies. So do institutional production arrangements, corporate incentives, public opportunity costs and foreign policy. For example, The New York Times called it a "rare and embarrassing reversal" when on Oct. 22, 1999, the ACIP withdrew its recommendation that all infants be immunized against rotavirus. The Times also noted that of the ACIP's then-12 members, only four voted – all for the recommendation. Other members were absent because of emergencies or abstained because of conflicts of interest. Nevertheless, rotavirus remains an issue: It is deadly in less developed countries.
Perspective is important in addressing vaccine and disease risks, as it is all risks. Former President Jimmy Carter reminded us in his speech at Georgia Tech's Ivan Allen College in 2002 that the greatest threat to security is the growing disparity between rich and poor countries.
And infectious diseases are still the leading cause of death globally. But prevention can be a hard sell, even though investing in prevention – in global education and public health – produces long-term benefits. Short-term benefits and risks too readily dominate policy debates. In this regard, vaccines for smallpox and other candidate bioweapons differ from other vaccines. They have the appealing immediate – if illusory – benefit of reducing the threat of bioterrorism.
Moving forward, thinking of vaccine policy as a subset of science and technology policy may provide new insights. As with other technologies, finding viable long-term research and development strategies and achieving sustainable production are critical to the success of mass immunization. The number of vaccine producers has dwindled dramatically in recent years, and a few childhood vaccines have been in short supply, suggesting a need for policy changes. Undoubtedly, parallels exist with technology transfer issues, as well. And for vaccines, as for other technologies, when public and private interests in vaccines compete, risk perceptions may get the last word.
Ann Bostrom is an associate professor in the Georgia Tech School of Public Policy. She conducts research in risk perception, communication and management.
photo courtesy CDC
photo courtesy CDC
For more information, contact Ann Bostrom, School of Public Policy, Georgia Tech, Atlanta, GA 30332-0345. (Telephone: 404-894-3196) (E-mail:
ann.bostrom@pubpolicy.gatech.edu) Also, you can get recent news about the smallpox vaccination at www.bt.cdc.gov or the Jan. 30, 2003, issue of the New England Journal of Medicine at http://nejm.org/earlyrelease/early.asp.
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Last updated: Jan. 6, 2003
