(April 2006) As if the global AIDS pandemic alone were not enough, developing countries are beset with converging epidemics of HIV and tuberculosis (TB)—increasing the likelihood of premature death in these countries.


TB and TB/HIV Coinfection Rates in Selected Countries, 2004

Note: Percentages of TB/HIV coinfection in all adults ages 15-49 in 2000 in these countries: Swaziland, 14; Lesotho, 8; Botswana, 14; Zimbabwe, 5; South Africa, 8.
Sources: WHO, Global Tuberculosis Control: Surveillance, Planning and Financing (2006); and E.L. Corbett et al., “The Growing Burden of Tuberculosis: Global Trends and Interactions with the HIV Epidemic,” Archives of Internal Medicine 163, no. 9 (2003).


Worldwide, 14 million people are coinfected with TB and HIV—70 percent of those in sub-Saharan Africa (see figure for five countries with particularly high coinfection rates).1 TB is the leading cause of death for those infected with HIV and is implicated in up to one-half of all AIDS deaths. And because HIV compromises the immune system, HIV-positive people are 50 times more likely to develop active TB than those who are HIV-negative.

The growing recognition of the connection between HIV and TB has motivated a global call by the World Health Organization (WHO) to address these epidemics in concert. Until now, efforts to mitigate the impact of these epidemics have occurred in isolation from each other:

  • The standard TB treatment—Direct Observed Therapy Short-Course (DOTS)—has been implemented in 182 countries and covers 77 percent of the world’s population.2 When followed appropriately, DOTS has been shown to be effective in curing 82 percent of TB cases in countries where it is widely used.3 Yet DOTS alone is not sufficient to address TB in countries with high HIV prevalence.
  • Multiple strategies have been designed to address the HIV epidemic—health promotion activities; voluntary counseling and testing (VCT); and provision of antiretroviral therapy (ART). In isolation, however, these interventions also cannot adequately address the intersecting epidemics.

The new solution is to utilize the infrastructure developed for each disease to also combat the other disease—in effect, to collaborate between TB and HIV/AIDS programs in providing a continuum of quality care at service-delivery level for people either living with or at risk of TB or HIV/AIDS. (People living with AIDS are often known by the acronym PLWHA.)

But the challenges to this approach are pervasive—the epidemics move quickly, and health systems may not be flexible enough to coordinate services. Additionally, health professionals working on TB (an age-old disease) and those working on the relatively younger HIV epidemic derive from vastly different health subcultures. Effective collaboration will mean overcoming conflicting priorities and dissimilar styles.

Two Diseases on a Collision Course

TB alone already has a profound impact on global health. Two million die of the disease every year, and nearly 9 million new active cases are diagnosed. TB can be cured with drugs that cost only $14-$18 per patient but may take six to nine months to work. And as a consequence of poor treatment, some strains of the Mycobacterium tuberculosis that causes TB no longer respond to treatment with the standard first-line drugs (see Antimicrobial Resistance Jeopardizes Medical Advancement). Multidrug-resistant TB (MDR-TB) has emerged in nearly every country in the world and accounts for 14 percent of all TB cases. The risk of MDR-TB is higher among HIV-infected persons than those who are not.4

HIV is also advancing rapidly: 40 million people worldwide were living with HIV at the end of 2005, 5 million more than in the previous year. Many infected with HIV develop TB as the first manifestation of AIDS, because HIV infection is the most potent risk factor for converting latent TB infection (which affects one-third of the world’s population) to active disease or relapse in previously treated patients.5 And where coinfection occurs, each disease speeds up the progress of the other, and together are more destructive than either one alone.

In some regions of Africa—where the number of new TB cases has more than quadrupled since 1990—75 percent of TB patients are HIV-infected. Although the global coinfection prevalence rate is only 0.36 percent, in eight African countries the prevalence rate exceeds 5 percent.6

Combating the Silo Approach

Although the confluence of these epidemics is more than a generation old, concerted joint efforts have only recently begun.7 One of the major impediments to integrating HIV and TB diagnosis, care, and treatment is the culture clash between the long-held separate traditions and practices of the TB and HIV enterprises.

While TB control has been undertaken through a standardized, methodical public health approach, HIV/AIDS care and treatment focuses on the individual with a strong human rights perspective and is characterized by quickly evolving treatment paradigms.8 HIV advocates, for example, have been quite successful in pressing for universal access to ART, and PLWHA have been intimately involved with communicating priorities and “owning” the HIV/AIDS treatment and prevention agenda. TB patients and experts have not been involved in the public health approach to their disease in the same way.

In developed countries, ART has resulted in a 70 percent decline in HIV/AIDS deaths.9 But ART has been difficult to access in developing countries until recently, when a number of initiatives have made expanded access a goal—most important, the WHO/UNAIDS “3 by 5” initiative (which aimed to bring ART to 3 million people by 2005) and the President’s Emergency Plan for AIDS Relief (or PEPFAR, which aims to bring ART to 2 million people by 2015). Most recently, the UN General Assembly announced a resolution to promote universal access to ART by 2010, marking a new phase in global mobilization on HIV/AIDS.

Momentum for joint efforts to address TB/HIV coinfection received its own rallying cry in 2004, when WHO published its Interim Policy on Collaborative TB/HIV Activities—the key strategy document on the problem. WHO’s strategy provides national governments and program managers with the essential minimum package of guidelines to address these intersecting epidemics. The package includes these recommendations:

  • Develop a coordinating body for TB/HIV activities, improved surveillance, and joint planning, monitoring, and evaluation.
  • To decrease the burden of TB among PLWHA, introduce an initiative to ramp up case-finding efforts for earlier detection of active TB in VCT centers; provide isoniazid preventive therapy for PLWHA, which prevents potential activation of latent TB; and provide TB infection control in health care and group settings.
  • To decrease the burden of HIV among TB patients, provide VCT for all TB patients in high-prevalence settings, screen TB patients for sexually transmitted infections (STIs), offer co-trimoxazole preventive therapy for secondary bacterial and parasitic infections, and introduce ART as an incentive for HIV testing.10

Unfortunately, all these recommendations require increased financial support at a time when absorptive capacities in developing countries are limited.

New Investment Brings Optimism, But Many Countries Still Face Disaster

The recent unveiling of the “Global Plan to Stop TB 2006-2015” and a new “Stop TB Strategy” by WHO and the Stop TB Partnership gave TB efforts an infusion of new optimism to the effort. Both these initiatives place strong emphasis on collaborative activities in countries with a high TB/HIV burden. The initiatives are designed to expand on the success of DOTS in order to achieve the Millennium Development Goal (MDG) target of cutting TB disease by one-half by 2015 compared with 1990 levels.11

An important component of these strategies is the development of new diagnostic and treatment tools with strong promise.12 While the horizon for developing such tools is long, the effort has been bolstered by a commitment by the Bill & Melinda Gates Foundation to triple their investment in TB research and development from $300 million to $900 million. By 2015, this funding is expected to generate simple diagnostic technologies (including rapid detection tools) at point of care; clinical identification of latent TB; new anti-TB drugs that will achieve a cure in one to two months, be effective against MDR-TB, and compatible with ARVs; and a new TB vaccine.13

While joint activities are critical in the battle against HIV/TB coinfections, there remain sticky issues of logistics and coordination at the country and local level as well as ethical issues that arise regarding integrating services. For example, offering TB testing in VCT settings is generally acceptable at the local level, but offering HIV testing at TB clinics may not be condoned in the context of the stigma associated with HIV status. Operational research is a priority at the field level to consolidate the TB/HIV collaborative approach.14

We can expect coinfection rates to rise in countries with high prevalence rates of TB—especially countries like India and China, where both the proportion and the volume affected may present enormous burdens to health systems. Risk of rising coinfection rates is also high in the six Asian countries—Bangladesh, China, India, Indonesia, Pakistan, and the Philippines—where one-half of all new global cases of TB arise.15

Additionally, where MDR-TB is prevalent (in countries such as Russia, Ukraine, and the Baltics) or where injection drug use is the predominant cause of HIV infection (such as Vietnam), coinfection may also gain a strong foothold. Without concerted efforts, the colliding epidemics could have devastating results in all these cases.


Heidi Worley is a senior policy analyst at the Population Reference Bureau.


References

  1. World Health Organization (WHO) and Stop TB Partnership, Fight AIDS, Fight TB, Fight Now: TB/HIV Information Pack (Geneva: WHO, 2004), accessed online at www.stoptb.org, on Feb. 14, 2006.
  2. WHO, Global Tuberculosis Control: Surveillance, Planning, Financing, Global Report 2005, accessed online at www.who.int, on March 16, 2006. DOTS consists of the following five components: diagnosis with TB sputum microscopy; standardized short-course chemotherapy, including direct observation of treatment at the community-level; secure drug supply; standardized reporting; and political will.
  3. WHO, Global Tuberculosis Control.
  4. L. Aaron et al., “Tuberculosis in HIV-Infected Patients: A Comprehensive Review,” Clinical Microbiology and Infection 10, no. 5 (2004): 388-98.
  5. UNAIDS/WHO, Global Summary of the AIDS Epidemic: December 2005 (Geneva: WHO, 2005).
  6. These countries are Swaziland (14 percent); Botswana (14 percent); Djibouti (10 percent); Zambia (9 percent); Namibia (9 percent); Lesotho (8 percent); South Africa (8 percent); and Malawi (6 percent).
  7. Elizabeth L. Corbett et al., “The Growing Burden of Tuberculosis: Global Trends and Interactions with the HIV Epidemic,” Archives of Internal Medicine 163, no. 9 (2003): 1009-21.
  8. WHO, TB/HIV Research Priorities in Resource-Limited Settings (Geneva: WHO, 2005), accessed online at www.who.int, on March 6, 2006.
  9. WHO, Fight AIDS, Fight TB, Fight Now.
  10. WHO, Interim Policy on Collaborative TB/HIV Activities (Geneva: WHO, 2005), accessed online at www.who.int, on Jan. 15, 2006. ART can reduce TB by up to 80 percent in people with HIV.
  11. The long-term goal of WHO and the STOP TB Partnership is to eliminate TB by 2050.
  12. WHO and Stop TB Partnership, The Global Plan to Stop TB 2006-2015 (Geneva: WHO, 2006).
  13. WHO and Stop TB Partnership, The Global Plan to Stop TB.
  14. WHO, TB/HIV Research Priorities in Resource-Limited Settings.
  15. WHO and Stop TB Partnership, The Global Plan to Stop TB 2006-2015.