This analytical profile on tuberculosis is structured as follows:
Up to 30% of the global tuberculosis (TB) disease burden occurs in Africa, with incidence doubling between 1990 and 2007. Death rates also doubled during this period. At present rates of progress, most countries are unlikely to reach the Millennium Development Goal target, despite significant progress in expanding DOTS (the basic package that underpins the Stop TB Strategy) coverage since 1990.
Health system weaknesses are considered mainly responsible for slower than desirable improvement in TB identification and care. Limited local-level diagnostic capacity, poor patient follow-up and shortages in drug supplies are contributing factors. Multidrug-resistant and extensively drug-resistant forms of TB, are emerging concerns attributed mainly to poor DOTS performance.
The true extent of multidrug-resistant and extensively drug-resistant TB in the WHO African Region is not known with accuracy. Problems are compounded by the irregular supply and high cost of second-line anti-TB medications. Training courses are being organized to build core capacity in addressing multidrug-resistant TB.
TB cannot be adequately controlled where:
- health systems remain weak, insufficiently decentralized, staffed or funded;
- there is inadequate laboratory back-up;
- drug supplies are uncertain.
These systemic problems need to be rectified. At the same time, it is imperative to engage strongly in partnership with all levels of health care providers, as well as with individuals and communities to contribute to health systems strengthening. As TB is a disease of the poor, and treatment costs are protracted, links with national anti-poverty mechanisms should be made both to reduce the costs to individuals and to address the upstream economic losses suffered by all countries with high TB disease burdens.
Africa is home to approximately 12% of the world population, but is estimated to carry up to 30% of the global burden of tuberculosis (TB).
The most recent estimate of TB incidence in Africa, carried out by WHO in 2007, reported a doubling of figures since 1990 (see figure), with a population ratio of 351:100 000. Prevalence has also greatly increased, with rates standing at 473:100 000 in 2008. Mortality figures have risen, more than doubling between 1990 and 2007.
While estimated TB incidence has been seen to decline since 2005, intensified action in all African countries is needed to maintain progress. At present rates, most countries will not attain the Millennium Development Goal target (see figure).
Expanding directly observed treatment short course (DOTS)
Significant progress in expanding DOTS coverage has been made since the beginning of the 1990s. An average coverage rate of 93% had been achieved throughout the WHO African Region by the end of 2008. By then, nine countries of the Region had reached the global target of a 70% case detection rate, compared with seven countries in 2007.
DOTS expansion and enhancement
Significant progress in expanding directly observed treatment short course (DOTS) coverage has been made since the beginning of the 1990s. An average coverage rate of 93% had been achieved throughout the WHO African Region by the end of 2008. By then, nine countries of the Region had reached the global target of a 70% case detection rate, compared with seven countries in 2007.
Case detection, treatment success and key challenges
The slow improvement in case detection is attributable to health system challenges. Chief among these are:
- limited human resources
- weak decentralization of diagnostic and clinical services to the periphery
- low levels of community engagement in identification and treatment of suspected cases.
While there has, in general, been an improvement in the quality of TB care in the Region, the treatment success rate has reached only 79%. This represents a marginal increase from 72% in the year 2000. Fifteen countries (Algeria, Benin, Burundi, Comoros, Democratic Republic of Congo, Eritrea, Kenya, Malawi, Mauritius, Rwanda, Sao Tome and Principe, Seychelles, Sierra Leone, United Republic of Tanzania, Zambia) attained the treatment success rate target of 85% in 2008, compared with only nine countries in 2007. Failure to meet the designated success rate is attributed mainly to high treatment default rates, transfers out, and death rates in several countries.
The principal challenge to DOTS implementation remains the weakness of national health systems. Typical shortfalls include:
- limited diagnostic capacity at community level
- inadequate mechanisms for patient follow-up during treatment
- high default and transfer out rates
- high death rates
- challenges in drug storage and distribution
- weak monitoring and evaluation systems.
MDR, TB/HIV and other challenges
Multidrug-resistant tuberculosis (MDR-TB) and extensively drug-resistant TB (XDR-TB) are emerging concerns in the WHO African Region. The commonest cause is poor basic performance of the DOTS (the basic package that underpins the Stop TB Strategy) programme. MDR-TB is defined as TB caused by organisms resistant to isoniazid and rifampicin, the two most potent first-line anti-TB medicines. XDR-TB is defined as MDR-TB cases that are also resistant to at least two of the key second-line anti-TB drug families (fluoroquinolones and second-line injectable agents). Both these forms of resistance bring a new dimension to the threat of the TB epidemic, and draw attention to the need for adequate resources to combat inadequacies in diagnosis, treatment and infection control in health institutions and communities.
The true extent of drug-resistant TB in Africa is not known. However, between January 2007 and December 2009, a total of 22 032 new MDR-TB cases had been reported in 33 countries. During the same period, 1501 new XDR-TB cases were reported in eight countries (Botswana, Burkina Faso, Kenya, Mozambique, Namibia, South Africa, Swaziland).
These figures may in fact represent only a fraction of the real total, since the Region has limited capacity to identify and monitor the treatment of drug-resistant TB strains. Thirteen countries do not have the local laboratory capacity to identify MDR-TB cases (Burundi, Cape Verde, Chad, Comoros, Congo, Eritrea, Gabon, Guinea-Bissau, Liberia, Mali, Niger, Sao Tome and Principe, Zimbabwe) , while only two (Algeria, South Africa) have the technical capacity to identify XDR-TB cases.
A further complication is the lack of second-line anti-TB medicines. This is partly due to the high cost and short shelf-life of some of these medicines. Of the 33 countries that have reported MDR-TB cases since 2007, only 20 are known to have a structured MDR-TB treatment programme, despite the existence of a WHO facility (the Green Light Committee mechanism) to ensure access to quality-assured second-line anti-TB medicines at concessionary prices. Four regional MDR-TB case management courses, two in the English language (organized with WHO headquarters) and two in French (organized with the International Union against TB and Lung Diseases), have been conducted to build core capacity for managing MDR-TB cases.
The HIV/AIDS epidemic has become the most important risk factor for TB incidence and death in the Region. Sub-Saharan Africa remains the most affected region, accounting in 2008 for over two thirds (67%) of all people living with HIV and nearly three quarters (72%) of AIDS-related deaths globally.
On average, 35% of new TB patients in the Region are coinfected with HIV, compared with 8% globally. TB-related death rates in countries with high HIV prevalence have risen to as much as 20% during the past 10 years. Coinfection increasingly causes TB to occur in younger, and hence more economically productive members of society, especially girls and young women aged between 15 and 24 years.
In 2006, 22% of TB patients were tested for HIV infection. By 2007, this had risen to 37%. The proportion in whom HIV infection was diagnosed and who started treatment with cotrimoxazol reached 66% in 2007, while 33% started antiretroviral therapy.
Contributing to health systems strengthening
Without a functioning health system, effective TB control interventions cannot be successfully implemented. Health system weaknesses have been identified in most Member States of the WHO African Region. Efforts to strengthen them focus mainly on:
- human resource development
- strengthening laboratory capacity
- bolstering procurement and supply management systems
- improving health information systems.
The Fifty-ninth session of the WHO Regional Committee for Africa, held in 2009, adopted Resolution AFR/RC59/R2 entitled "Drug resistance related to AIDS, tuberculosis and malaria: issues, challenges and the way forward". This Resolution called on Member States to strengthen national and subnational health laboratory networks, including human resources capacity, and to implement administrative, environmental, personal protection, and integrated infection control measures, particularly for multidrug-resistant TB and extensively drug-resistant TB.
WHO continues to provide assistance to Member States in implementing the provisions of this Resolution.
Engaging all care providers
The WHO Stop TB Strategy recognizes the need to engage with all health care providers, utilizing the public–private mix approach in implementing DOTS. Currently, most African countries have public–private mix DOTS initiatives in place, primarily involving organized private care providers and industry-related health services.
However, a significant proportion of countries are still not including informal health care providers in their DOTS activities. Mechanisms established with countries to further DOTS outreach should ensure that all levels of health care providers are engaged, thereby increasing outreach for the identification, referral, diagnosis and treatment of suspected TB cases. Existing experience in some countries has shown that informal sector providers can successfully support the DOTS approach.
Empowering people with TB, and communities
Tuberculosis (TB) is a disease of the poor. An infected individual becomes poorer due to the costs of a protracted process of diagnosis and treatment. A 2004 joint report by the African Union and the Economic Commission for Africa estimated an annual economic loss of 4–7% of gross domestic product in countries with a high TB disease burden.
Economic loss on this scale underscores the need for well-defined linkages between TB control and national antipoverty initiatives geared to reaching poor and vulnerable populations. These include the Poverty Reduction Strategy Papers, Medium Term Expenditure Frameworks, Poverty Reduction Support Credits, and other broad planning mechanisms such as the Sector-wide Approach. Formal linkages of this nature will help ensure sustainability of commitment to TB control. The WHO Regional Office for Africa will assist this process by systematically promoting the incorporation of pro-poor approaches in the formulation of national TB control strategies.
The Regional Office has provided technical support to countries through provision of guidance for community TB care, based on results of the project ‘Community TB Care in Africa’, and lessons from other disease control programmes. These successful patient-centred and community-based initiatives have shown the importance of building a partnership between patients, communities and the formal health system. They have demonstrated that this partnership is feasible, cost effective and acceptable. Moreover, the sociocultural traditions of African communities offer a sound departure point to enhance the involvement of patients and communities in measures to address the scourge of TB and other killer diseases.
State of surveillance
Recording and reporting of tuberculosis cases is systematically carried out by countries and reported annually to WHO. Disease measurement through prevalence surveys has been identified as a priority need in the 2010/2011 reporting period. Surveys will take place in 11 African countries this year. These are currently at different stages of preparation and implementation, but the outputs are expected to improve present estimates of the tuberculosis disease burden throughout the continent.
Enabling and promoting research
The WHO Regional Office for Africa supports countries in the development and implementation of programme-based operational research, and the documentation of best practices within the WHO African Region. However, this area requires significant further human and financial resourcing to become more effective.
Endnotes: sources, methods, abbreviations, etc.
- ↑ 1.0 1.1 1.2 1.3 WHO global tuberculosis control: a short update to the 2009 report. Geneva, World Health Organization, 2009 (WHO/HTM/TB/2009.426)
- ↑ AIDS epidemic update 2009 (pdf 2.9Mb). Geneva, Joint United Nations Programme on HIV/AIDS and World Health Organization 2009
- ↑ Drug resistance related to AIDS, tuberculosis and malaria: issues. Challenges and the way forward (pdf 28.53kb). Resolution AFR/RC59/R2 http://www.afro.who.int/index.php?option=com_docman&task=doc_download&gid=3852
- ↑ Scoring African leadership for better health. Addis Ababa, Economic Commission for Africa, 2004 http://www.uneca.org/eca_resources/Publications/Scoring/index.htm
- ↑ Draft guidelines for implementing community TB care programmes. Brazzaville, World Health Organization Regional Office for Africa, 2004