The Twin Epidemics: HIV and TB Co-infection

Setting the Scope

An estimated 2 billion people – one-third of the global population – are infected with tuberculosis (TB), and each year, 8.7 million people develop TB disease. TB kills more than 1.4 million people each year and is economically devastating to families and communities worldwide. Although TB is a global problem, its geographic distribution is drastically disproportionate. Ninety-five percent of all TB cases and 98 percent of all TB deaths occur in developing countries. TB is one of the top killers of women and is responsible for 500,000 of their deaths each year. TB is a major killer among women of reproductive age and the leading cause of death in HIV-positive individuals. Only 22 high-burden countries (HBCs) account for 80 percent of the global TB burden, with half of these countries located in Asia. In Africa, 40 countries have an estimated TB prevalence rate greater than 100/100,000 compared to an estimated prevalence rate of <5/100,000 in the United States.

The global resurgence of TB has been fueled by a combination of factors, including increasing rates of HIV/AIDS and multidrug resistance, inadequate investments in public health infrastructure, insufficient political commitment, limited awareness of TB, disparities in access to and quality of health care services, and inadequate investments in new tools, including drugs, diagnostics, and vaccines. The disease threatens the poorest and most marginalized, disrupts the social fabric of society, and slows or undermines gains in economic development.

Progress on the Stop TB Partnership and DOTS Expansion

Significant progress has been made since the Stop TB Partnership was launched in 2000. The Amsterdam Ministerial Conference on Tuberculosis and Sustainable Development, held in March 2000, established global targets of 70 percent TB case detection and 85 percent treatment success rates in smear-positive pulmonary TB cases to be achieved by the year 2005 in the 22 HBCs. The first Global Plan 2001–2005 served to catalyze governments and donors to address TB. The number of countries implementing DOTS (directly observed treatment, short-course), the most effective strategy available for the treatment and control of TB, increased from 112 in 1998 to 184 by 2006.

Building on this momentum, in January 2006, the Stop TB Partnership launched the Global Plan to Stop TB 2006–2015, which includes the Millennium Development Goal target of halting and beginning to reverse the incidence of TB by 2015, as well as the more ambitious Stop TB targets of reducing TB prevalence and deaths by 50 percent by 2015, relative to the 1990 baseline. The Global Plan describes the actions and resources needed to combat the epidemic and achieve these targets. The World Health Organization (WHO) and other Stop TB partners also launched a more robust technical approach known as the Stop TB Strategy, which builds on DOTS. There is strong global commitment to combat TB and to collaborate on that effort: The Partnership has grown to more than 1,000 members, including endemic countries, donors, nongovernmental organizations (NGOs), research organizations, and other institutions.

To date, much progress has been made in achieving these goals. New cases of TB have been declining each year and fell to >2 percent between 2010 and 2011. The TB mortality rate has decreased by 41 percent since 1990 and is on track to reach the global target of 50 percent reduction by 2015. However, the job is far from done, with an estimated 8.7 million new cases and 1.4 million deaths annually.

HIV and TB Co-infection

HIV/AIDS and TB co-infection present special challenges to the expansion and effectiveness of DOTS programs and the Stop TB Strategy. TB accounts for one-quarter of AIDS deaths worldwide and is one of the most common causes of morbidity in people living with HIV and AIDS (PLWHA). Currently, approximately 34 million people are infected with HIV, and at least one-third of them are also infected with TB. The dual epidemics of TB and HIV are particularly pervasive in Africa, where HIV has been the most important contributing factor in the increasing incidence of TB over the last 10 years. In some countries in sub-Saharan Africa, up to 80 percent of individuals with active TB disease are also HIV-positive. The dual epidemics are also of growing concern in Asia, where two-thirds of TB-infected people live and where TB now accounts for 40 percent of AIDS deaths. Eastern Europe and the former Soviet Union have the fastest growing HIV epidemic in the world, a factor further exacerbating the expanding problem of the multidrug-resistant TB (MDR-TB) epidemic in these regions. The overlap of TB-HIV co-infection with MDR-TB and extensively drug-resistant TB presents a tremendous challenge and threatens progress in controlling TB and HIV and AIDS and in eliminating the mortality associated with these diseases.

Individuals co-infected with HIV and TB are 30 times more likely to progress to active TB disease. Infection with TB enhances replication of HIV and may accelerate the progression of HIV infection to AIDS. Fortunately, TB treatment under the DOTS programs is just as effective in individuals with HIV as it is in people who are HIV negative. In addition, clinical trials have shown that there are anti-TB regimens that can prevent or decrease the likelihood of TB infection progressing to active TB disease in an HIV-infected individual, making it an important intervention for increasing the length and quality of life for those co-infected and their families and communities.

Strategic Engagement with the U.S. President’s Emergency Plan for AIDS Relief

Within the U.S. Government, the U.S. President’s Emergency Plan for AIDS Relief (PEPFAR), primarily through the U.S. Agency for International Development (USAID) and the Centers for Disease Control and Prevention (CDC), leads funding and implementation of HIV-TB co-infection activities. Given the importance of TB-HIV as part of a comprehensive TB program, USAID supports TB-HIV activities within the Agency’s TB programs and closely coordinates its efforts with other PEPFAR agencies. Specifically, USAID supports the threefold strategy established in 2004 by WHO to enhance collaborative efforts between TB and HIV/AIDS programs; to decrease the burden of TB in PLWHA; and to decrease the burden of HIV in TB patients.

Read the FY 2011/12 Report to Congress on TB [PDF, 5.33MB]
Accelerating Impact. Expanding Access to Care: U.S. Government Report to Congress on International Foreign Assistance for Tuberculosis FY 2011/2012 highlights key programmatic achievements and collaboration of the different U.S. Government agencies involved in global TB programs, bringing comparative expertise to address the many challenges of TB. It includes the latest data on key results for USAID-funded TB activities and highlights successful projects in Malawi, Brazil, Afghanistan, and Cambodia, among others.

USAID’s Three-Fold Strategy for HIV/TB

To address the first component of the strategy, USAID supports coordination of TB and HIV/AIDS services by improving collaboration among TB and HIV programs, host countries and donor agencies, NGOs, and research institutions; developing training programs for TB specialists/program managers on HIV counseling and testing and management of co-infected patients; strengthening the links between TB services and HIV testing and HIV care services; and exploring the use of alternative service delivery approaches, such as community- and home-based care and involving faith-based organizations in such approaches. Such coordination is essential in ensuring early diagnosis; appropriate referral; and prompt, quality care for each disease.

To address the second component, decrease the burden of TB in PLWHA, USAID supports improvements in TB screening, prevention, and treatment through links with facilities that provide care and antiretroviral therapy (ART) services. Identification or exclusion of active TB in individuals who are HIV positive is critical to ensuring access to appropriate services. However, in 2006, only approximately 300,000 HIV-positive individuals were screened for TB through the collective efforts of the global TB and HIV communities. By 2010, greatly expanded efforts resulted in the screening of 2.3 million, and by 2011, that number increased by 39 percent to 3.2 million HIV-positive individuals. Identification of these dually-infected individuals enabled access to critical, lifesaving TB treatment for those diagnosed with active TB, and access to preventive TB treatment for those who did not have active TB. USAID also provides assistance to programs that strengthen and expand HIV and TB surveillance to improve the quality and availability of TB-HIV-related data and to those implementing infection control measures in clinical settings with high rates of HIV and TB.

To address the third component, USAID supports programs and operations research that seeks to decrease the burden of HIV in TB patients. Support is provided to increase access to HIV testing and counseling and establish a system of referrals between TB and HIV/AIDS programs, and by training TB program personnel in HIV testing. The efforts of the global community significantly increased HIV screening among TB patients from approximately 4 percent in 2004 to 40 percent globally (and 69 percent in Africa) in 2011. USAID also supports programs to promote the use of therapies proven to diminish the morbidity and mortality associated with TB-HIV co-infection, including co-trimoxazole preventive therapy (CPT) in adults and children living with HIV and AIDS, and ART in eligible TB patients. USAID’s assistance, combined with that of our partners, led to increased uptake of CPT (from 66 percent in 2007 to 79 percent in 2011) and ART (from 30 percent in 2007 to 48 percent in 2011) among co-infected individuals. USAID also supports innovative service delivery models for reaching co-infected patients, monitors and analyzes the effectiveness of such models, and works with partners to scale up successes.

Significant progress in mitigating the TB-HIV epidemic has been made over the past several years through coordinated, collaborative efforts to diagnose HIV among TB patients, diagnose TB among individuals with HIV, and conduct research in new technologies and methodologies to improve both diagnosis and treatment. New diagnostics, particularly Xpert MTB/RIF, which can quickly (<2 hours) identify susceptible and resistant TB and is almost twice as accurate identifying TB in HIV-positive individuals compared with traditional methods, offer great possibilities for rapid diagnosis and treatment of those co-infected. USAID, together with its U.S. Government and global partners, is introducing and expanding access to this technology, particularly in areas of high HIV prevalence. Additionally, for the first time in many years, multiple new TB drugs and drug regimens appropriate for use in both HIV-negative and HIV-positive individuals are being evaluated and are expected to be available in the next several years. These innovations, in conjunction with advances in the delivery of care and improved partnerships with communities and the private sector, are key to further progress in reducing the morbidity and mortality TB and HIV-TB co-infection.