In some areas of the world, one in four people with tuberculosis (TB) becomes ill with a form of the disease that can no longer be treated with standard drugs regimens, a World Health Organization (WHO) report says.
For example, 28% of all people newly diagnosed with TB in one region of north western Russia had the multidrug-resistant form of the disease (MDR-TB) in 2008. This is the highest level ever reported to WHO. Previously, the highest recorded level was 22% in Baku City, Azerbaijan, in 2007.
In the new WHO’s Multidrug and Extensively Drug-Resistant Tuberculosis: 2010 Global Report on Surveillance and Response, it is estimated that 440 000 people had MDR-TB worldwide in 2008 and that a third of them died. In sheer numbers, Asia bears the brunt of the epidemic. Almost 50% of MDR-TB cases worldwide are estimated to occur in China and India. In Africa, estimates show 69 000 cases emerged, the vast majority of which went undiagnosed.
Tuberculosis programmes face tremendous challenges in reducing MDR-TB rates. But there are encouraging signs that even in the presence of severe epidemics, governments and partners can turn around MDR-TB by strengthening efforts to control the disease and implementing WHO recommendations.
Two regions in the Russian Federation, Orel and Tomsk, have achieved a remarkable decline in MDR-TB in about five years. These regions join two countries, Estonia and Latvia, which have reversed rising high rates of MDR-TB, ultimately achieving a decline. The United States of America and China, Hong Kong Special Administrative Region (SAR), have achieved sustained successes in controlling MDR-TB.
Progress remains slow in most other countries. Worldwide, of those patients receiving treatment, 60% were reported as cured. However, only an estimated 7% of all MDR-TB patients are diagnosed. This points to the urgent need for improvements in laboratory facilities, access to rapid diagnosis and treatment with more effective drugs and regimens shorter than the current two years.
WHO is engaged in a five year project to strengthen TB laboratories with rapid tests in nearly 30 countries. This will ensure more people benefit early from life-saving treatments. It is also working closely with the Global Fund to Fight AIDS, Tuberculosis and Malaria and the international community on increasing access to treatment.
Multidrug-resistant TB (MDR-TB) is caused by bacteria that are resistant to at least isoniazid and rifampicin, the most effective anti-TB drugs. MDR-TB results from either primary infection with resistant bacteria or may develop in the course of a patient’s treatment.
Extensively drug-resistant TB (XDR-TB) is a form of TB caused by bacteria that are resistant to isoniazid and rifampicin (i.e. MDR-TB) as well as any fluoroquinolone and any of the second-line anti-TB injectable drugs (amikacin, kanamycin or capreomycin).
These forms of TB do not respond to the standard six-month treatment with first-line anti-TB drugs and can take up to two years or more to treat with drugs that are less potent, more toxic and much more expensive, from 50 to 200 times higher. While a course of standard TB drugs cost approximately US$ 20, MDR-TB drugs can cost up to US$ 5 000, and XDR-TB treatment is far more expensive.
In 2008, there were an estimated 9.4 million new TB cases, and 1.8 million TB deaths. 440 000 MDR-TB cases are estimated to have emerged in the same year with 150 000 MDR-TB deaths. No official estimates have been made on the number of XDR-TB cases, but there may be around 25 000 a year with most cases fatal. Since XDR-TB was first defined in 2006, a total of 58 countries have reported at least one case of XDR-TB.
Funding MDR-TB control
In 27 high burden countries (i.e. countries estimated to have had at least 4000 MDR-TB cases arising annually and/or at least 10% of newly registered TB cases with MDR-TB), 1.3 million M/XDR-TB cases will need to be treated between 2010 and 2015 at a cost of US$ 16 billion over six years, rising from US$ 1.3 billion in 2010 to US$ 4.4 billion in 2015. Planned budget for 2010 are far below these figures, amounting to less than US$ 0.5 billion for all 27 countries. Actual funding available for 2010 was US$ 280 million. Funding needed for MDR-TB control in 2015 will be 16 times higher than what is currently available in 2010.
There is an urgent need to expand and accelerate in countries access to new, rapid technologies that can diagnose MDR-TB in two days rather than traditional methods which can take up to four months. EXPAND TB is a five year project targeting 27 countries, launched in 2008 and implemented by WHO, the Foundation for Innovative New Diagnostics (FIND), the Stop TB Partnership’s Global Drug Facility (GDF) and the Global Laboratory Initiative (GLI) with financial support from UNITAID. So far it has carried out a wide range of activities in 12 countries, including upgrading of infrastructure and training of staff. Technology transfer has started in countries, paving the way for more patients to be diagnosed accurately and rapidly enrolled on treatment. These upgrades should lead to eventual routine surveillance of drug resistance in affected countries.
Countries and case studies
Six countries are featured throughout the report in special focus sections. Bangladesh (one of the very few developing countries in which continuous surveillance among previously treated TB cases is being carried out in selected areas); China (first nationwide drug resistance survey conducted); Ethiopia (one of the first countries to introduce rapid molecular laboratory tests); Nepal and Romania (successful treatments of MDR-TB through Green Light Committee Initiative programmes); South Africa (policy changes for improving the management and care of M/XDR-TB).
MDR-TB in Africa
In Africa, there is a low percentage of MDR-TB reported among new TB cases compared with that in regions such as Eastern Europe and Central Asia, due in part to the limited laboratory capacity to conduct drug resistance surveys. Latest estimates of WHO put the number of MDR-TB cases emerging in 2008 in Africa at 69 000. Previous reports found high levels of mortality among people living with HIV and infected with MDR-TB and XDR-TB. In KwaZulu Natal in South Africa, an outbreak of XDR-TB killed 52 out of 53 people within three weeks, most of whom were HIV positive.
Risk factors: HIV and MDR-TB
Studies show that TB patients co-infected with HIV in three Eastern European countries (Estonia, Latvia, and the Republic of Moldova) were at a higher risk of having MDR-TB compared to TB patients without HIV infection. Similar findings have been made in studies from Lithuania, Ukraine and Mozambique.
The report highlights several reasons why drug-resistant TB may be associated with HIV, particularly in some Eastern European countries. However, more research is needed to determine whether there is an overlap between the MDR-TB and HIV epidemics worldwide.
Reporting on MDR-TB globally
This report presents drug resistance data from 114 countries and updated information from 35 of them. Despite the growing understanding of the magnitude and trends in drug-resistant TB, major gaps remain in geographical areas covered. Since 1994, only 59% of all countries globally have been able to collect high quality representative data on drug resistance. There is an urgent need to obtain information, particularly from Africa and those high MDR-TB burden countries where data have never been reported: Bangladesh, Belarus, Kyrgyzstan, Pakistan and Nigeria. Moreover, countries need to expand the scope of their surveys to cover entire populations, repeat surveys are needed to better understand trends in drug resistance and countries need to move towards adopting systematic continuous surveillance.
Source: World Health Organization, Switzerland