CDC's Response to Ending Neglect
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The documents listed below are historical, archived information. The information contained in these documents, while accurate at the time of release, may not be the most current available.
Introduction
Historical Perspective
Tuberculosis (TB), once the leading cause of death in the United States, appeared to be receding into history by the latter part of the 20th century. Thanks to improved social and economic conditions and the development of effective drugs, TB case counts had fallen off so dramatically by the 1980s that U.S. TB experts believed TB could be virtually eliminated from the United States by the year 2010. The Advisory Council for the Elimination of Tuberculosis (ACET) developed and outlined these projections in A Strategic Plan for the Elimination of Tuberculosis in the United States, which was published by the Centers for Disease Control and Prevention (CDC) in 1989. In this document, ACET proposed a national strategy for TB elimination, defined as an incidence rate of less than one TB case per 1 million persons per year.1 Actions to achieve that goal centered on making better use of existing TB prevention and control methods; creating and evaluating new tools for diagnosing, treating, and preventing TB; and rapidly applying these tools to clinical and public health practice.
The implementation of this plan was set back by the unexpected resurgence of TB that occurred in the mid 1980s and early 1990s. The reversal of the longstanding downward trend in TB incidence was fueled by several converging factors: the onset of the human immunodeficiency virus (HIV) epidemic, increases in TB cases among foreign-born persons, outbreaks in congregate settings (e.g., hospitals, correctional facilities, hospices), and delays in recognizing the appearance and transmission of deadly, drug-resistant TB strains that defy traditional treatments.2-4 At the same time, premature cuts in TB funding and the subsequent deterioration of TB prevention and control programs impaired the ability of these programs to respond to the resurgent TB. The National Action Plan to Combat Multidrug-Resistant Tuberculosis was promptly developed and published in 1992 to complement the 1989 TB elimination plan.5
During the past decade, these plans have guided the nation's TB control programs and propelled its mobilization against the resurgent TB. Efforts to implement the strategies recommended in these plans have been largely successful, as evidenced by a renewed downturn in TB incidence).6,7 Nonetheless, some emerging changes in the features and management of TB in the United States are challenging control efforts and threatening to thwart the drive toward elimination:
- As numbers of TB cases have steadily dropped, the disease has retreated into localized areas and population groups who may be hard to reach using the traditional public health approaches, so that it can lie hidden and resist detection. The persistence of TB in these high-risk populations poses threats for yet another widespread comeback.
- Although screening and treatment efforts have led to great progress in blocking the spread of TB, it has become increasingly clear that elimination will require better tests and treatments, plus an improved vaccine.8
- Despite falling numbers of cases in the United States and in a few other resource-rich countries, the global TB epidemic continues to rage in many other countries, and remains an important source of new U.S. cases in the person of immigrants and refugees. As of 2001, TB cases in foreign-born persons now account for at least 50% of all cases reported in the United States annually.7 In contrast to the marked decline in TB case rates in U.S.-born persons, the TB control measures implemented in the early 1990s have had little impact on TB case rates in foreign-born persons.9
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Changes in the organization, delivery, and financing of health care brought about by the shift to managed care make the current context for TB prevention, control, and elimination very different from that of a decade ago.10
Given this altered landscape, in late 1998 CDC commissioned the Institute of Medicine (IOM) of the National Academy of Sciences to conduct a study to determine if TB elimination is still feasible as a national goal and, if so, to provide recommendations for making that goal a reality. In the resulting report, Ending Neglect: The Elimination of Tuberculosis in the United States,11 the IOM concluded that TB elimination in the United States is indeed feasible but that meeting this goal will require "aggressive and decisive action beyond what is now in effect." Current efforts in TB control will not be sufficient, and doing less could be disastrous. To break the "cycle of neglect" that has characterized U.S. tuberculosis control efforts, the report recommended an aggressive campaign to release TB's tenacious grip on the nation.
At the current rate of decline in TB incidence, it is estimated that it will take at least 70 years to reach the U.S. elimination goal of less than 1 case per million population by the target year of 2010. To speed progress toward elimination, the IOM pressed for an acceleration in the rate of reduction in the incidence of new TB cases. Stepping up the pace would yield numerous benefits to the nation11 by reducing the
- Number of persons suffering with TB
- Costs of medical care for TB patients
- Risk of a resurgence of TB
- Risk of multidrug-resistant TB (MDR TB)
- Risk of spread to TB-free areas of the United States
- Complications caused by TB in HIV-infected persons
Additionally, it would contribute to a reduction in the global burden of TB and hasten the eventual elimination of TB from the United States.
CDC's Response to Ending Neglect: The Elimination of Tuberculosis in the United States outlines the background and rationale for eliminating TB in the United States and presents the goals, objectives, and action steps that comprise CDC's new strategy for TB elimination. The plan will serve as a guide for CDC's work, in collaboration with its partners, to finally rid the nation of the human suffering and societal harm caused by TB disease.
TB: A Preventable and Treatable Disease
Tuberculosis is a contagious and potentially life-threatening infectious disease caused by bacteria of the Mycobacterium tuberculosis complex. The bacteria that cause TB are spread from person to person through the air. People with TB disease of the lungs or larynx spray the bacteria into the area when they cough, sneeze, talk, or otherwise expel air, dispersing droplets containing M. tuberculosis. People nearby can breathe the infectious droplets into their lungs and become infected. Infection usually requires prolonged contact in a confined area with a person who is actively expelling TB bacteria into the air. In rare cases, TB infection has been documented after short exposures to persons with active TB.12,13
In most infected persons, merely harboring TB organisms is not enough to cause symptoms or to produce an active case of the disease. The body's immune system is usually able to contain the infection but may not be able to eliminate it without help from anti-TB drugs. A person with latent TB infection remains infected until correct treatment is completed. Without treatment, infected persons can develop active, clinical disease at any time. The persons most likely to become ill are those whose immune systems have been weakened by illness, old age, or malnutrition. To spread TB to others, a person must have active TB disease.
TB maintains its grim historical notoriety as one of the leading infectious causes of death worldwide; yet, it is preventable and, in most cases, treatable. Infection-control precautions can help reduce the risk of TB transmission. Treatment of persons with latent TB infection can prevent the subsequent development of active TB, and TB disease can usually be cured with available anti-TB drugs. Even persons with drug-resistant strains can often be cured by alternative regimens of medications. Nonetheless, TB continues to menace Americans. Several closely interconnected social, political, and medical factors persist in fueling disease transmission and imperiling elimination goals.
Cycles of Resurgence and Control
The resurgence of the U.S. TB epidemic that occurred in the late 1980s had its origins in the complacency of the early 1970s. When medical advances and improved societal conditions seemed to be controlling TB by the 1960s, funding dedicated to fighting the disease was prematurely cut. The result was a breakdown in control efforts in many parts of the country. TB soon returned with a vengeance. Disease rates jumped, deadly drug-resistant strains emerged, and new outbreaks in the late 1980s quickly turned into an epidemic that cost billions of dollars to control3, 14 and also cost many people their health or even their lives. Hundreds of difficult- and expensive-to-treat drug-resistant cases developed. The nation had dropped its guard, and a preventable and treatable disease had once again turned deadly.
Studies conducted during the period of resurgence (1985-1992) indicated substantial ongoing transmission of TB and development of disease in larger-than-expected numbers in recently infected persons.15, 16 However, in a pattern suggesting the existence of several concurrent U.S. epidemics, the phenomenon appeared to be mainly affecting certain high-risk populations: HIV-infected persons (TB thrives in a weakened immune system), foreign-born persons (people from areas where TB is common often have latent TB infection), homeless persons (TB is easily spread in the crowded confines of homeless shelters), and persons living in congregate settings (persons with unrecognized or undiagnosed TB are often housed among susceptible people in close quarters). The increase in the number of persons with drug-resistant TB was attributed largely to institutional outbreaks involving persons with HIV infection.3, 4 The rise in total cases, coupled with increased drug resistance, created formidable challenges for state and local control programs.5
The comeback of TB prompted the mobilization of improved prevention and control efforts. These centered on rapid identification of persons with TB, initiation of appropriate treatment, and implementation of strategies such as directly observed therapy (DOT) to ensure that patients complete their treatment.17, 18, 19 Many areas expanded their TB screening and treatment efforts directed toward high-risk groups, especially persons at risk for HIV infection and those in correctional facilities. Surveillance data and research on adherence to treatment further characterized risk groups, leading to more targeted interventions. In parallel with these surveillance and research activities, public health agencies produced much-needed training and educational products for health care providers, with timely development of materials to reflect clinical advances and changing TB epidemiology. ACET and CDC jointly issued a series of statements on TB control practices, and three Model TB Centers were established as national resources for TB services, consultation, and training. As a result, cases have dropped each year since 1993, reaching an all-time low in 2001.7
Challenges to Elimination
The downturn in TB incidence that has occurred since 1993 is directly associated with the increased resources used to strengthen state and local TB control programs nationwide.11 The question now is whether this success will lead to complacency, then to waning interest and another cycle of neglect, or provide the impetus for a final push toward TB elimination. At a minimum, future planning for TB control will have to address several recalcitrant problems.
Proven and essential measures that would improve the timely completion of TB treatment are underused in many areas.20 In addition, the investigation of contacts of infectious cases and the treatment of persons with latent TB infection are often inadequate.21,22 In some areas where TB case counts have been declining, an erroneous and dangerous perception is again emerging that TB may no longer be a serious problem requiring sustained resources. With such perceptions, we risk losing what we have recently gained.
The marked changes in the provision and financing of health care in the United States that have come about as a result of managed-care policies and practices during the past decade present added challenges for TB control. Nearly 80 million Americans are now enrolled in health-maintenance organization plans.10 Managed-care programs serve one third of Medicaid beneficiaries, with enrollment in such programs growing at the rate of 30% to 40% annually.23 The opportunity exists for TB control programs to work with managed-care programs in the provision of high-quality and potentially cost-saving preventive TB services to high-risk persons.24, 25 However, it is uncertain to what extent these organizations will support optimal TB surveillance and reporting, as well as provide treatment and prevention services. Additionally, the large numbers of uninsured persons not covered by managed-care plans pose an ongoing challenge to TB prevention and control efforts.
TB control is also hampered by inefficient and outdated diagnostic tools. The current TB skin test takes 2 days to complete, is difficult to read, and is often inaccurate in populations with a low prevalence of TB. Technological advances can help speed the way toward TB elimination, but methods for optimizing the use of new technology are still being evaluated. The past decade has seen notable advances in TB diagnostics, including the development of new methods that greatly reduce the time needed to detect the growth of TB organisms in diagnostic specimens.26-27 Rapid methods for identifying drug-resistant TB are under investigation,28, 29 and new blood tests for detecting latent TB infection show promise.26, 27, 29-33 DNA fingerprinting methods have been used to identify M. tuberculosis strains implicated in outbreaks, and the role of these methods in detecting ongoing community TB transmission is being assessed.32, 34
The TB drug development process is moving more slowly than diagnostics development. Scientists have made advances in describing the mechanisms of drug actions and drug resistance, and these advances are contributing to the development of new types of anti-TB drugs. In 1997, CDC established the TB Trials Consortium (TBTC) and tasked it with undertaking clinical trials of new drugs for TB treatment and prevention in the United States. TBTC data assisted the Food and Drug Administration (FDA) in its evaluation in 1998 of rifapentine, the first new TB drug approved in more than 25 years.35 Clinical trials of "short-course" treatment for latent TB infection have led to CDC recommendations for the use in selected settings of a 2-month regimen of the anti-TB drugs rifampin and pyrazinamide as an alternative to longer courses of isoniazid.36 Unfortunately, despite the need for new drugs, too few pharmaceutical companies are involved in TB drug development.37
A significant research effort is being directed to the development of new TB vaccines. The successful decoding of the complete genome of M. tuberculosis should accelerate the process of vaccine development,38 and several candidate vaccines will likely be available soon for human testing. In 1998, the National Institutes of Health (NIH), together with the National Vaccine Program Office (NVPO) and ACET, issued the Blueprint for Tuberculosis Vaccine Development.39 The agencies concluded that a safe and protective TB vaccine could be developed but that the effort would require a sustained and substantive commitment (20 years and approximately $800 million) and international and public-private sector collaboration.
Most importantly, the United States' recent success in TB control is tempered by the heavy impact of TB in foreign-born persons living in the country. The global burden of TB is staggering, with nearly 8 million new cases and 2 million deaths each year.40 As the number of cases in indigenous persons drops, an increasing percentage of U.S. cases is occurring in persons from Asian, Latin American, and African countries, where TB rates are 5 to 30 times those of the United States.41 The TB case rate for foreign-born persons in the United States has remained at least four to five times higher than that for U.S.-born persons, and the proportion of U.S. TB cases occurring in foreign-born persons has increased steadily since the mid-1980s.9 In 2001 the proportion of TB cases among foreign-born persons living in the United States had reached 50% (see graph).7
TB elimination in the United States will therefore not be possible without a substantial reduction in the global burden of TB. Global TB control efforts are, however, hampered by a combination of barriers. Foremost among these is the inability of the governments of some TB-affected nations to develop the political will needed, and of some donor nations to provide the financial resources needed, for effective TB control. The World Health Organization (WHO) estimates that in 1997 only 32% of the world's population lived in areas where effective TB control programs were fully operational.42 In much of sub-Saharan Africa, HIV has led to the doubling and tripling of TB cases, threatening to collapse unstable TB control programs.43 To date, it appears that none of the strategies for TB control recommended for low-income countries have stemmed the tide of HIV-associated TB. Increases in drug-resistant TB add urgency to the push for effective interventions worldwide.40, 44
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