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Editorials |
1 From the Department of Radiology, Indiana University School of Medicine, 702 Barnhill Dr, Room 1053, Indianapolis, IN 46202-5200. Received May 16, 2006; revision requested July 19; revision received August 10; final version accepted September 1. Address correspondence to R.B.G. (e-mail: rbgunder{at}iupui.edu).
According to many public health experts, a pandemic of avian influenza represents one of the greatest and most urgent threats to the health of the population of the United States. Anthony Fauci, MD, Director of the Institute for Allergy and Infectious Diseases at the National Institutes of Health, has said that "the prospect of pandemic influenza provides good reason to be concerned ... If (the new viral strain) acquires the ability to transmit readily among humans, an influenza pandemic could ensue, with the potential to kill millions of people" (1). According to Julie Gerberding, MD, MPH, Director of the Center for Disease Control and Prevention, "We are seeing a highly pathogenic strain of influenza emerge across the entire western component of Asia. The reason this is so ominous is because of the evolution of flu. You may see the emergence of a new strain to which the human population has no immunity. The science here is all alerting us that we have a great deal to be concerned about" (2).
As members of the profession of medicine, it is important that radiologists understand the nature of the public health risk posed by pandemic influenza. In the event of a pandemic due to a respiratory virus, radiologists would have crucial roles to play in the diagnosis of disease, gauging disease extent and severity, monitoring response to treatment, and assessing for treatment complications. Chest radiography and computed tomography (CT) would likely play an especially important role. Likewise, radiologists need to understand the ethical ramifications of pandemics, including social disruptions to which a pandemic could give rise, the allocation of scarce health care resources, and the duty of health professionals to provide care even when it places our own health at risk (3).
What is a pandemic? Derived from the Greek roots pan meaning "all" and demos meaning "people," a pandemic occurs when the health of a large number of individuals around the globe is threatened by infectious disease. For a pandemic to occur, several conditions must be met. First, a new disease must emerge, such as human immunodeficiency virus/acquired immunodeficiency syndrome or a new strain of influenza capable of causing disease in humans. Second, this disease must be spread to the human population. In the case of most recent strains of influenza, this involves transmission from birds to human beings. Third, the disease must be capable of causing serious health effects in human beings. The common cold is a ubiquitous infectious disease, but it does not pose a serious threat to health. Finally, the disease must be readily and sustainably transmitted from human to human.
An example of a readily transmissible disease is measles, which afflicts virtually every exposed person who does not already possess immunity. Cancer is now the number one killer of adults under the age of 85 years, yet it cannot qualify as a pandemic because it is not transmissible from person to person (although some forms of cancer, such as carcinoma of the uterine cervix, are strongly related to infection by human papilloma virus) (4,5). A highly lethal disease may fail to be sustainably transmitted because it kills hosts too rapidly, before other victims can be infected. Natural selection should tend to favor pathogens that do not inflict too much damage on their host, and the best "pathogens" of all may be commensal species, such as the bacteria that normally inhabit the human intestines and even benefit us by producing vitamin K.
How close have we come recently to a severe pandemic of influenza? A number of conditions have been satisfied. First, novel viral subtypes are arising in animals, especially poultry in southern China. Second, some of these viruses have been able to replicate in ways that cause human disease. The missing ingredient over the past few decades has been efficient human-to-human transmission. People who come into contact with birds have fallen ill, but the viruses have not been able to move from person to person effectively. The question is not if such human-to-human transmission will occur, but when, and when it does it is imperative that our health systems be prepared. Says Dr Fauci, "We cannot be certain when the next influenza pandemic will emerge, or even whether it will be caused by H5N1 or an unrelated virus. However, we can be certain that an influenza pandemic eventually will occur" (1).
The World Health Organization, WHO, has devised a staging system for pandemics (6). The first two phases are part of the interpandemic period. In phase 1, no new viral subtypes are found in human beings. In phase 2, animal variants arise that threaten human disease. The next three phases occur during a pandemic alert period. In phase 3, there is disease in humans, but no human-to-human transmission. In phase 4, there is localized human-to-human transmission, such as in a hospital. In phase 5, infection occurs in larger clusters but is still localized, such as in a particular town or city. The pandemic period is phase 6, when there is sustained transmission in the general population. At the time of this writing, we are in a pandemic alert period, phase 3.
It is important to note that influenza is already a daily fact of life throughout the world, especially during the winter months. Each year, it is estimated that as many as 500 000 people worldwide die of influenza, with approximately 36 000 deaths per year in the United States (7,8). These deaths typically occur among the very old and debilitated. Members of such groups, as well as health professionals who might transmit the viruses, are advised to undergo immunization against new threatening strains of influenza each year. What most frightens public health officials is the appearance of a new and highly virulent strain that spreads efficiently from person to person.
We can glimpse the potentially dire consequences of a pandemic by examining past episodes (9). In 430 BC, during the war between Athens and Sparta, a plague arose among the Athenians, who had retreated behind their city walls into overcrowded conditions. This plague, now known to be typhoid, resulted in the deaths of approximately one-third of the population and eventually killed off hosts faster than they could spread it. In 541 AD in Constantinople, the plague of Justinian, a type of bubonic plague, killed 40% of the city's inhabitants, up to 10 000 people per day. Similarly, the black death in Europe, caused by infection from Pasteurella pestis, killed one-fourth of the European population, at least 34 million people in just 6 years. These plagues were associated with a breakdown of general social order, widespread panic, and psychological and social suffering that extended far beyond the numbers of lives lost.
A number of influenza pandemics have occurred over the past century or so and appear to do so at the rate of 2–3 per century (10). These pandemics have included the Asiatic influenza of 1889–1890, the Asian influenza of 1957–1958, and the Hong Kong influenza of 1968–1969. By far the deadliest influenza pandemic in living memory was the great worldwide influenza pandemic of 1918, which killed between 20 and 50 million people. One of the distinguishing features of this pandemic was the fact that half of the victims were young adults in the prime of life, and as many as 10% of young adults then living may have lost their lives (11). As Dr Fauci has suggested, if such a pandemic were to strike today, it might claim the lives of as many as 1 million Americans (1).
Pandemics raise a number of important ethical issues in the area of resource allocation. First, they force us to take stock of the extant resources available to respond to them. These resources include money, people, space, time, and the general level of knowledge, skill, and commitment of those responding to the challenge. An example of issues in resource allocation is how to divide resources between the most severely ill patients who require intensive care and those patients with milder disease. Likewise, how would we distribute resources between caring for the ill and preventing the spread of disease to those not yet infected? The United States currently leads the world in per capita spending on health care ($5635), devoting a greater percentage (15%) of its gross domestic product to health than any other nation (12). Yet those resources are not necessarily well aligned to meet the threat of pandemic influenza.
If anything, we have been falling further and further behind in our level of pandemic preparedness. For example, the number of inpatient hospital beds in the United States actually decreased by 4.4% from 1996 to 2000, which is a reduction of 38 000 beds. Between 1995 and 2001, the number of intensive care unit (ICU) beds decreased by 20% (13). Many beds that are theoretically available cannot be used because of a shortage of health professionals, especially nurses, to staff them. And the need for resources is affected not only by the number of infected individuals but also by the severity and length of their illnesses. During the outbreak of severe acute respiratory syndrome (SARS), the average ICU stay was 10.5 days, and the average hospital stay was 18 days (14). During the post-9/11 anthrax scare, many of those who were infected and were once thought to be mortally ill turned out to be "salvageable" with new intensive support. Biomedical technologies continue to increase the possibility of survival in the face of severe illness and, accordingly, the need for health professionals. Our surge capacity, the ability to meet a sudden spike in demand for such resources, is at best limited.
Consider the following hypothetical case (15). In a metropolitan area of 1 million people, a pandemic of influenza infects 10% of the population, or 100 000 people. Of these, 20%, or 20 000, are too sick to care for themselves. Of these, a further 20%, 4000, lack friends and family members who can care for them. Most cities of this size in the United States do not have several thousand spare hospital beds, including ICU beds, to care for such patients. Even if entire hospitals were isolated for use only as treatment centers of pandemic influenza, as might be necessary for quarantine purposes, there would be a shortage of necessary space to handle a patient volume of pandemic proportions. Likewise, stores of vaccines and antiviral medications are limited. Further, vaccine stores would be useful only if the pandemic viral strain exhibits minimal antigenic variations from viruses already selected for vaccine production, which is not certain (16). The federal government plans to produce 81 million doses of oseltamivir antiviral drug, which would provide doses for one-quarter of the U.S. population (17). From a global point of view, there is sufficient manufacturing capacity to produce immunizations for only 5% of the world's people, and 90% of that capacity is located in Europe and North America, which are home to only 10% of the world's population.
Shortages of such resources will inevitably require policymakers and health care professionals to develop triage criteria. These criteria might be derived from a number of different principles that collide with one another to varying degrees, thereby making prioritization a necessity (18). One such criterion is effectiveness of care, the principle that care should be directed first to those patients for whom it is likely to make the biggest difference. A related criterion is probability of survival, which is grounded in the idea that scarce resources are best limited to those patients who are most likely to survive their illness. Another such criterion is resource utilization, which is based on the principle that triage decisions should maximize the efficient use of available resources. One especially problematic criterion is the value of patients' lives, because such assessments tend to be subjective and undermine the idea that all human beings are equally valuable.
Allocation criteria may also vary depending on whether the decision is to withhold or to withdraw treatment. Some health professionals are comfortable establishing strict criteria for withholding treatment but are more reluctant to withdraw life-sustaining support. Examples of criteria for withdrawal of mechanical ventilation might include multi-organ system failure or failure to improve after several days of ventilation (19). Age is yet another "thorny" issue. Certainly older patients tend to have lower survival rates and stand to gain fewer years of life as a result of intervention, but specific age limits, such as 65 years, can be difficult to enforce (what if grandfather just turned 65 yesterday?), and chronologic age is an imperfect proxy for biologic age. There is also the difficult issue of preexisting conditions. For example, should potentially life-saving care be withheld from patients because they are disabled or have a serious disease such as cancer?
Uncomfortable with most efforts to establish allocation criteria, some commentators have suggested that the only truly fair approach is a random approach (18). This approach could take the form of a lottery, or it could rest on some other basis, such as "first come, first served." A common criticism of the random approach is its failure to take into account the effectiveness, efficiency, and cost of resource utilization. For example, during a pandemic, epidemiologic studies might clearly demonstrate dramatically different outcomes for different categories of patients, and ignoring such findings could be construed as wasting resources.
Some have suggested that members of certain groups in our society should have first access to vaccines and antiviral medications (18). One such group might be workers in the health system. These would include physicians, nurses, laboratory workers, scientists, and administrators, as well as a number of other essential personnel in the health care system. Another group placed at the top of the priority list is composed of critical infrastructure personnel, including first responders (such as firefighters and emergency medical technicians), security forces (such as police and national guard), essential services personnel (water, food, and sanitation workers), utilities personnel (telecommunications, gas, and electricity), and certain government officials. Others have suggested that medical need should be a factor, placing the most seriously ill and vulnerable high on the priority list for vaccines and antiviral drugs (18). Still another approach would privilege the financially able—groups such as the rich, the powerful, and the politically connected. Conversely, some would distribute resources first to underserved populations.
Whatever allocation procedure is chosen, policymakers and health professionals need to bear in mind the possibility that the system will not be universally adhered to. There is always the possibility of favoritism of one kind or another. Some people may hoard resources out of fear or a desire to turn a profit. It is even possible that black markets in precious health care goods and services might arise.
Steps to contain a pandemic would likely take several forms. In the effort to reduce bird-to-human transmission, people could, as much as possible, be kept away from poultry. Infection control procedures such as masks and disinfectants could be implemented. Flocks of birds could be culled. It is important to recognize that steps such as culling flocks of infected birds could be economically disastrous for low-income farmers in Asia, many of whom operate at a subsistence level (20). Hygiene, including hand washing, using a handkerchief or other barrier when coughing or sneezing, and wearing gloves, would also be important for the general population. Social interaction would need to be curtailed and would possibly include the closing of schools, child care centers, and workplaces. Public events might need to be canceled.
Such separation would likely have adverse consequences, such as further isolation of the elderly and the infirm (21). As the threat of contagion makes people increasingly fearful of one another, emotional detachment would probably increase. Individuals who were already lonely might grow only more so. The economic consequences of a pandemic could be severe and could include the temporary or permanent loss of workers owing both to illness and to absenteeism of people who choose to stay at home. In times of crisis, many people turn to communities of worship, but such public assemblies might not be possible because of quarantines (either official or self-imposed quarantines). Legal challenges to public health measures could arise on the basis of the right to free association in the U.S. Constitution. In any such public health emergency, a balance would need to be struck between promoting the public good and protecting individual liberty (22).
There is also the duty of health care workers, including radiologists, to provide care. During the outbreak of SARS in Asia in 2004, dozens of health care workers became infected (due in part to a failure to follow universal precautions), and some deaths occurred. Those who reject the idea that health professionals have a duty to care argue that everyone's first responsibility in a public health emergency is to protect their own health. This idea tends to treat patients as threats to be avoided. Moreover, by avoiding contact with infected individuals, health care workers would also protect the health of other patients and their family and friends. Finally, health care workers have responsibilities to provide for their own families, which would not be possible if they became seriously ill or died from disease. Similar arguments could be advanced for other professionals, such as soldiers, firefighters, and police.
On the other hand, proponents of the duty of health professionals to provide care argue that no one else in society is better prepared to care for the sick. If health care professionals do not do it, they ask, who will? Moreover, health care professionals freely chose to enter their profession and, thus, assumed responsibilities to provide care. Some would argue that professions such as medicine and nursing have a social contract to serve the sick. Society invests health professionals with special privileges precisely so that they will be available when the need arises (23). Thus, radiologists, radiologic technologists, radiology nurses, and other radiology department personnel appear to have a moral duty to attempt to meet the health care needs of our community in a public health emergency. To fail to answer that call would be an abrogation of professional responsibility.
These responsibilities may extend beyond individual health professionals to institutions, as well. For example, hospitals have a duty to provide for the health and safety of their workers and to provide care for those who become ill while on duty. Similarly, health insurance companies have a duty to ensure that they provide timely claims service to those in need. Institutions need to develop fair and workable human resource plans that take into account the possibility that substantial numbers of workers may be unable to report for work because of their own illnesses or the illnesses of family members. Decision-making support should be available for physicians, nurses, and administrators wrestling with difficult allocation choices, and provisions need to be made for psychological and spiritual care.
In summary, it is vital that radiologists clearly understand the nature of a potential influenza pandemic, do our part in helping to formulate strategies for prevention and response, and consider the ethical implications of the countermeasures and resource allocation decisions that would be involved. By limiting individual liberties, public health responses have complex ethical and legal implications that require careful consideration.
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