Tuberculosis (TB)

WHO report 2009 - Global tuberculosis control

Epidemiology, strategy, financing

KEY POINTS

Purpose and methods

1. This report is the 13th annual report on global control of tuberculosis (TB) published by the World Health Organization (WHO) in a series that started in 1997. Its main purpose is to provide a comprehensive and up-to-date assessment of the TB epidemic and progress in controlling the disease at global, regional and country levels, in the context of global targets set for 2015. Results are based primarily on data reported to WHO via its standard TB data collection form in 2008 and on the data that were collected every year from 1996 to 2007. The 196 countries and territories that reported data in 2008 account for 99.6% of the world’s estimated number of TB cases and 99.7% of the world’s population.

Global targets for TB control

2. The main targets for global TB control are (i) that the incidence of TB should be falling by 2015 (MDG Target 6.c), (ii) that TB prevalence and death rates should be halved by 2015 compared with their level in 1990, (iii) that at least 70% of incident smear-positive cases should be detected and treated in DOTS programmes and (iv) that at least 85% of incident sputum smear-positive cases should be successfully treated. The latest data suggest (i) that the incidence rate has been falling since 2004, (ii) that prevalence and death rates will be halved in at least three of six WHO regions by 2015 compared with a baseline of 1990, but that these targets will not be achieved for the world as a whole, (iii) that the case detection rate reached 63% in 2007 and (iv) that the treatment success rate reached 85% in 2006.

Epidemiological burden of TB

3. Globally, there were an estimated 9.27 million incident cases of TB in 2007. This is an increase from 9.24 million cases in 2006, 8.3 million cases in 2000 and 6.6 million cases in 1990. Most of the estimated number of cases in 2007 were in Asia (55%) and Africa (31%), with small proportions of cases in the Eastern Mediterranean Region (6%), the European Region (5%) and the Region of the Americas (3%). The five countries that rank first to fifth in terms of total numbers of cases in 2007 are India (2.0 million), China (1.3 million), Indonesia (0.53 million), Nigeria (0.46 million) and South Africa (0.46 million). Of the 9.27 million incident cases in 2007, an estimated 1.37 million (14%) were HIV-positive; 79% of these HIV-positive cases were in the African Region and 11% were in the South-East Asia Region.

4. Although the total number of incident cases of TB is increasing in absolute terms as a result of population growth, the number of cases per capita is falling. The rate of decline is slow, at less than 1% per year. Globally, rates peaked at 142 cases per 100 000 population in 2004. In 2007, there were an estimated 137 incident cases per 100 000 population. Incidence rates are falling in five of the six WHO regions (the exception is the European Region, where rates are approximately stable).

5. There were an estimated 13.7 million prevalent cases of TB in 2007 (206 per 100 000 population), a decrease from 13.9 million cases (210 per 100 000 population) in 2006.

6. An estimated 1.3 million deaths occurred among HIV-negative incident cases of TB (20 per 100 000 population) in 2007. There were an additional 456 000 deaths among incident TB cases who were HIV-positive; these deaths are classified as HIV deaths in the International Classification of Diseases (ICD-10). The 456 000 deaths among HIV-positive incident TB cases equate to 33% of HIV-positive incident cases of TB and 23% of the estimated 2 million HIV deaths in 2007.

7. Prevalence and mortality rates are falling globally and in all six WHO regions. The Region of the Americas as well as the Eastern Mediterranean and South-East Asia regions are on track to achieve the Stop TB Partnership targets of reducing prevalence and death rates by 50% by 2015, compared with a baseline of 1990. The Western Pacific Region is on track to halve the prevalence rate by 2015, but the mortality target may be narrowly missed. Neither the prevalence nor the mortality targets will be met in the African and European regions. The gulf between prevalence and mortality rates in 2007 and the targets in these two regions make it unlikely that 1990 prevalence and death rates will be halved by 2015 for the world as a whole.

8. The estimated numbers of HIV-positive TB cases and deaths in 2007 are approximately double the numbers published by WHO in previous years. This does not mean that the number of HIV-positive TB cases and the number of TB deaths among HIV-positive people doubled between 2006 and 2007. New data that became available in 2008, particularly from provider-initiated HIV testing in the African Region, were used (i) to estimate the numbers of cases and deaths in 2007 and (ii) to revise previous estimates of the numbers of cases and deaths that had occurred in earlier years. The numbers of HIV-positive TB cases and deaths are estimated to have peaked in 2005, at 1.39 million cases (15% of all incident cases) and 480 000 deaths.

9. The latest estimates of the numbers of HIV-positive TB cases and deaths were based, as usual, on estimates of HIV prevalence in the general population published by the Joint United Nations Programme on HIV/AIDS, or UNAIDS. The new data that became available in 2008 were direct measurements of the proportion of TB cases that are coinfected with HIV in 64 countries (up from 15 countries in 2007). These 64 direct measurements suggest that HIV-positive people are about 20 times more likely than HIV-negative people to develop TB in countries with a generalized HIV epidemic (compared with a previous estimate of six), and between 26 and 37 times more likely to develop TB in countries where HIV prevalence is lower (compared with a previous estimate of 30). These higher estimates were used to estimate the number of HIV-positive TB cases in countries for which direct measurements were not available.

10. There were an estimated 0.5 million cases of multidrug-resistant TB (MDR-TB) in 2007. There are 27 countries (of which 15 are in the European Region) that account for 85% of all such cases. The countries that rank first to fifth in terms of total numbers of MDR-TB cases are India (131 000), China (112 000), the Russian Federation (43 000), South Africa (16 000) and Bangladesh (15 000). By the end of 2008, 55 countries and territories had reported at least one case of extensively drug-resistant TB (XDR-TB).

11. The WHO Global Task Force on TB Impact Measurement has produced recommendations about how to measure progress in reducing rates of TB incidence, prevalence and mortality (the three major indicators of impact). These include systematic analysis of national and subnational notification data combined with improved surveillance systems to measure incidence, surveys of the prevalence of TB disease in 21 global focus countries between 2008 and 2015, and strengthening of vital registration systems to measure TB mortality among other causes of death. Implementation of Task Force recommendations is necessary to improve measurement of progress towards the global targets set for 2015 as well as to measure progress in TB control in subsequent years.

Implementation of the Stop TB Strategy

12. The Stop TB Strategy is WHO’s recommended approach to reducing the burden of TB in line with global targets. The six major components of the strategy are: pursue high-quality DOTS expansion and enhancement; address TB/HIV, MDR-TB, and the needs of poor and vulnerable populations; contribute to health system strengthening based on primary health care; engage all care providers; empower people with TB, and communities through partnership; and enable and promote research. The Stop TB Partnership’s Global Plan to Stop TB, 2006–2015 sets out the scale at which the interventions included in the Stop TB Strategy need to be implemented to achieve the 2015 targets.

13. In 2007, 5.5 million TB cases were notified by DOTS programmes (99% of total case notifications). This included 2.6 million smear-positive cases. The case detection rate of new smear-positive cases under DOTS (that is, the percentage of estimated incident cases that were notified and treated in DOTS programmes) was 63%, a small increase from 62% in 2006 but still 7% short of the target of ≥70% first set for 2000 (and later reset to 2005) by the World Health Assembly (WHA) in 1991. The target was met in 74 countries and in two regions – the Region of the Americas (73%) and the Western Pacific Region (77%). The South-East Asia Region (69%) almost met the target. The case detection rate was 60% in the Eastern Mediterranean Region, 51% in the European Region and 47% in the African Region.

14. Globally, the rate of treatment success for new smear-positive cases treated in DOTS programmes in 2006 reached the target of 85% first set by the WHA in 1991. Three regions – the Eastern Mediterranean (86%), Western Pacific (92%), and South-East Asia (87%) regions – met the target, as did 59 countries. The treatment success rate was 75% in the African Region and the Region of the Americas, and 70% in the European Region.

15. In 2006–2007, the Western Pacific Region and 36 countries met both the target of a case detection rate of at least 70% and the target of a treatment success rate of at least 85% for new smear-positive cases. The South-East Asia Region is close to achieving both targets. Kenya became the first country in sub-Saharan Africa to achieve both targets.

16. There has been major progress in implementing interventions such as testing TB patients for HIV and providing co-trimoxazole preventive therapy (CPT) and antiretroviral therapy (ART) to HIV-positive TB patients. Globally, 1 million TB patients (16% of notified cases) knew their HIV status in 2007. The greatest progress in HIV testing was in the African Region, where 0.5 million TB patients (37% of all notified cases) knew their HIV status in 2007. Of the 250 000 HIV-positive TB patients, 0.2 million were enrolled on CPT and 0.1 million were started on ART. In both cases, figures were higher than those reported to WHO in previous years.

17. Despite the progress that has been made with scaling up collaborative TB/HIV activities, progress in HIV testing is outpacing progress in the provision of CPT and ART. The number of HIV-positive TB patients being treated with CPT and ART is small compared with the 0.3 million TB patients known to be HIV-positive, and smaller still compared with the estimated 1.4 million HIV-positive TB cases (many of whom are not detected in DOTS programmes, given a case detection rate of 47%). Case detection in DOTS programmes as well as collaborative TB/HIV activities need to be expanded to ensure that (i) many more people know their HIV status and (ii) that those who are HIV-positive, with and without TB, have access to appropriate and timely treatment and care.

18. Globally, just under 30 000 cases of MDR-TB were notified to WHO in 2007, mostly by European countries and South Africa. This was 8.5% of the estimated global total of smear-positive cases of MDR-TB. Of the notified cases, 3681 were started on treatment in projects or programmes approved by the Green Light Committee (GLC), and are thus known to be receiving treatment according to international guidelines. This is equivalent to 1% of the estimated global total of smear-positive cases of MDR-TB. The number of patients started on treatment in GLC-approved projects and programmes is expected to increase to around 14 000 in 2009, equivalent to 4% of the smear-positive cases of MDR-TB estimated to exist globally. To meet the targets set in the Global Plan, diagnosis and treatment of MDR-TB need to be rapidly scaled up, especially in the three countries that account for 57% of global cases: China, India and the Russian Federation.

19. Diagnostic and treatment services for TB are integrated into primary health care in most countries.

20. National plans for TB control are aligned with national health strategies in more than half of the 22 high-burden countries (HBCs). Most NTPs are also involving other ministries, associations and institutions in the development of their plans. With renewed emphasis on health system strengthening, there is a strong basis for closer collaboration on key challenges such as sustainable financing, human resource development, infection control and health information systems.

21. The contribution of public–private mix (PPM) initiatives to detection and treatment of TB cases is difficult to quantify in most countries, but examples such as Pakistan and the Philippines (where public–private partnerships accounted for 19% and 8% of all notifications, respectively) illustrate their potential to contribute to increased case detection. The contribution of communities to diagnosis and treatment of TB is also hard to quantify. Many countries require guidance and support to design, implement and evaluate advocacy, communication and social mobilization activities (ACSM).

Financing

22. A total of US$ 3.0 billion is available for TB control in 2009 in 94 countries that reported data, and which account for 93% of the world's TB cases: of this total, 87% is funding from governments (including loans), 9% is funding from Global Fund grants and 4% is funding from donors other than the Global Fund. Most of the available funding is in the European Region (US$ 1.4 billion, mostly in the Russian Federation), followed by the African Region (US$ 0.6 billion) and the Western Pacific Region (US$ 0.3 billion). The funding gaps identified by these 94 countries amount to US$ 1.2 billion in 2009.

23. The total of US$ 4.2 billion required for full implementation of country plans in these 94 countries in 2009 is mostly for DOTS (US$ 3 billion, or 72%). The other major components are MDR-TB (US$ 0.5 billion, or 12%; 76% of the total for MDR-TB is accounted for by the Russian Federation and South Africa), collaborative TB/HIV activities (US$ 120 million, or 3%) and ACSM (US$ 100 million, or 2%). The remaining 11% includes PPM, surveys of the prevalence of TB disease, community-based TB care and a variety of miscellaneous activities.

24. In the 22 HBCs where 80% of the world’s TB cases occur, a total of US$ 2.2 billion is available in 2009, a small increase of US$ 27 million compared with 2008 but substantially above the US$ 1.2 billion that was spent on TB control in 2002 (when WHO began financial monitoring of TB control). Most of the increased funding since 2002 has come from domestic funding in Brazil, China and the Russian Federation, and external financing from the Global Fund. The HBCs reported a combined funding gap of US$ 0.5–0.7 billion in 2009 (the range reflects uncertainty about the level of funding from provincial governments in South Africa).

25. The total of US$ 2.9 billion required for full implementation of country plans in the 22 HBCs in 2009 is mostly for DOTS (US$ 2 billion, or 69%). The other major components are MDR-TB (US$ 0.4 billion, or 14%; 88% of this total is accounted for by the Russian Federation and South Africa), TB/HIV (US$ 90 million, or 3%) and ACSM (US$ 70 million, or 2%). The remaining 12% includes PPM, surveys of the prevalence of TB disease, community TB care and a variety of miscellaneous activities.

26. Of the US$ 2.2 billion available in the 22 HBCs in 2009, 88% is from HBC governments, 8% (US$ 169 million) is from the Global Fund and 4% (US$ 94 million) is from grants from sources other than the Global Fund. The distribution of funding sources is different when the Russian Federation and South Africa are excluded: the government contribution to available funding drops to 70%, the Global Fund contribution increases to 19% and grants from sources besides the Global Fund account for 11%.

27. The gap between the available funding reported by the 22 HBCs in 2009 and the funding requirements for these countries according to the Global Plan in 2009 is US$ 0.8 billion. The gap between the available funding reported by the 94 countries with 93% of global cases in 2009 and the funding required for these countries in 2009 according to the Global Plan is US$ 1.6 billion. Most of the extra funding required according to the Global Plan is for MDR-TB diagnosis and treatment in the South-East Asia and Western Pacific regions (mostly in India and China), and for DOTS and collaborative TB/HIV activities in Africa.

28. The global burden of TB is falling slowly, and at least three of six WHO regions are on track to achieve global targets for reducing the number of cases and deaths that have been set for 2015. However, while increasing numbers of TB cases have access to high-quality anti-TB treatment as well as to related interventions such as ART, an estimated 37% of incident TB cases are not being treated in DOTS programmes, up to 96% of incident cases with MDR-TB are not being diagnosed and treated according to international guidelines, the majority of HIV-positive TB cases do not know their HIV status and the majority of HIV-positive TB patients who do know their HIV status do not have access to ART. To accelerate progress in global TB control, these numbers need to be reduced using the range of interventions and approaches included in the Stop TB Strategy.

Share