Global tuberculosis epidemic has levelled off

Mar 22 2007

The global tuberculosis (TB) epidemic has levelled off for the first time since WHO declared TB a public health emergency in 1993. The Global Tuberculosis Control Report released today by WHO finds that the percentage of the world's population struck by TB peaked in 2004 and then held steady in 2005.

"We are currently seeing both the fruits of global action to control TB and the lethal nature of the disease’s ongoing burden," said United Nations Secretary-General Ban Ki-moon. "Almost 60 per cent of TB cases worldwide are now detected, and out of those, the vast majority are cured. Over the past decade, 26 million patients have been placed on effective TB treatment thanks to the efforts of governments and a wide range of partners. But the disease still kills 4400 people every day."

Although the rate at which people developed TB in 2005 was level or even declined slightly compared to 2004, the actual number of TB cases continued to rise slowly. The reason for this difference is that world population is expanding. The pace at which new TB cases developed in 2005, however, was slightly lower than global population growth. The number of cases in 2005 was 8 787 000, up from 8 718 000 in 2004. An estimated 1.6 million people died of the disease in 2005, 195 000 of them people living with HIV.

Despite signs that the epidemic may be slowing, there are major impediments to rapid progress against TB - prominent among them being uneven access to diagnosis and treatment within countries. "We need to tackle this problem as part of the larger challenge of increasing access to primary health care services. All people, no matter who they are or where they live, should have access to TB diagnosis and treatment as part of a package of general health services that bring multiple health benefits," said Dr Margaret Chan, WHO Director-General.

Other major barriers to progress include:

HIV/TB: TB is a major cause of death among people living with HIV/AIDS, and HIV is the main reason for failure to meet TB control targets in high HIV settings, particularly sub-Saharan Africa, where HIV/AIDS is dramatically fuelling the TB epidemic. Collaboration between TB and HIV programmes is key to reducing the burden of TB among people living with HIV.

HIV among TB patients: The report finds that HIV testing for TB patients is increasing rapidly in Africa, but few people living with HIV are being screened for TB. "In the last year, we have seen unprecedented collaboration between the TB and HIV communities, but much more is needed if we are to achieve our goal of universal access to quality TB and HIV prevention, diagnostic, treatment and care services", said Dr Peter Piot, Executive Director of UNAIDS.

Extensively drug-resistant TB (XDR-TB): The spread of XDR-TB poses a serious threat to progress and could even reverse recent gains. "We have a clear plan on how to control XDR-TB, but countries are moving far too slowly on implementing this plan. Funding is an issue as well -- it will take an additional US$ 650 million globally to implement control of both XDR-TB and multi-drug-resistant TB (MDR-TB) in 2007 alone," said Dr Mario Raviglione, Director of the WHO Stop TB Department. "Beyond that, because of the threat of XDR-TB, research to identify new diagnostics, drugs and vaccines is more vital than ever."

Overall funding gap: Although funds for TB control have risen substantially since 2002, reaching US$ 2 billion, an additional US$ 1.1 billion will be needed to meet the 2007 funding requirements set by the Global Plan to Stop TB (2006-2015). A total of US$ 56 billion--half of which should be funded by endemic countries and the other half by donors--is needed for the 10-year plan, but current funding commitments indicate a gap of at least US$ 31 billion.

Lack of infrastructure and capacity: In most countries with a high burden of TB, efforts to fight TB are impeded by inadequate laboratory facilities and critical shortages of health staff.

Should a sustained downward trend in the TB epidemic develop, it is likely that the Millennium Development Goal of achieving a decrease in the number of tuberculosis cases per year will be satisfied years in advance of the 2015 target. But much more rapid progress is needed for countries to meet the targets in the Global Plan to Stop TB: to halve 1990 TB case numbers and deaths from the disease by 2015.

The report finds that the WHO Regions of the Americas, South-East Asia and the Western Pacific are now on track to meet their 2015 Global Plan targets, while the African, Eastern Mediterranean and European regions are not. WHO's 2005 targets of 70% case detection and 85% cure were narrowly missed globally: case detection was 60% and treatment success was 84%.

The Stop TB strategy of WHO has six components:

• pursue high-quality DOTS expansion and enhancement
• address TB/HIV, MDR-TB and other challenges
• contribute to health system strengthening
• engage all care providers
• empower people with TB, and communities
• enable and promote research

Multidrug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB)

TB can usually be treated with a course of four standard, or first-line, anti-TB drugs. If these drugs are misused or mismanaged, multidrug-resistant TB (MDR-TB) can develop. MDR-TB takes longer to treat with second-line drugs, which are more expensive and have more side-effects. XDR-TB can develop when these second-line drugs are also misused or mismanaged and therefore also become ineffective. Because XDR-TB is resistant to first- and second-line drugs, treatment options are seriously limited and the risk of death is extremely high. Both MDR-TB and XDR-TB can be spread from person to person.

The Global Plan to Stop TB (2006-2015), launched by the Stop TB Partnership in January 2006, sets forth a roadmap for treating 50 million people for TB and enrolling 3 million patients who have both TB and HIV on antiretroviral therapy over the next 10 years, saving about 14 million lives. It aims to halve TB prevalence and deaths compared with 1990 levels by 2015.