Feature Story

Photo credit : WHO

Tuberculosis (TB) is one of the biggest killers of people living with HIV and at least one third of the 39.5 million people estimated to be living with HIV around the world are likely to be infected with the TB bacteria. As a result of chronically poor investment in global TB control a new strain of TB is emerging that has become resistant to most of the available anti-tuberculosis drugs. Known as extensively drug resistant TB (XDR TB) this strain has serious implications for people living with HIV as it is almost untreatable in many of the countries where it is occurring leading to very high death rates. WHO and UNAIDS, together with other actors working on TB and HIV issues are stepping up action to stop the spread of TB and this deadly new strain.

TB is an infection which usually affects the lungs and is spread, like the common cold, through the air from an infectious person coughing, sneezing or even speaking. One third of the world’s population is infected with TB but only 5-10% of people who are infected with TB actually develop TB disease during their lifetimes. However, co-infection with HIV makes TB disease much more likely and one in ten people infected with TB who also have HIV will develop TB disease each year.

TB is treatable and can usually be cured in people living with HIV, however some strains of TB bacteria have now acquired resistance to one or more of the antibiotics commonly used to treat them; these are known as drug-resistant strains. Treatment for these infections is much longer and much more expensive. The recent outbreaks of tuberculosis that is resistant to almost all of the available TB drugs are giving serious cause for concern as this extensively drug resistant strain (XDR TB) is virtually untreatable when it occurs in people living with HIV and has a very high death rate.

UNAIDS has been following the developments closely. “We need to rapidly ensure prompt diagnosis and effective treatment of TB for people living with HIV in order to prevent drug resistance from developing and spreading,” said UNAIDS’ HIV/TB advisor, Alasdair Reid.

TB drug resistance arises mainly because of inadequate TB control, poor patient or clinician adherence to standard TB treatment regimens, poor quality drugs or inadequate drug supplies. People living with HIV are particularly vulnerable to developing drug-resistant TB because of their increased susceptibility to infection and progression to active TB.

At the 37th Union World Conference on Lung Health held in Paris in November 2006, the interaction between TB and HIV and the threat of extensively drug resistant TB featured prominently in the agenda. The serious implications of the new strain of XDR TB for people living with HIV were highlighted at a special plenary session held during the conference. Dr Kevin De Cock, Director of WHO HIV/AIDS Department said, “The recent emergence of a cluster of cases in South Africa has demonstrated the high mortality that XDR TB can have when associated with HIV infection. Countries with a high prevalence of HIV have been responding quickly to draw up plans for managing and preventing drug-resistant TB and this is welcomed.”

Because of the serious threat that TB and especially XDR TB poses for people living with HIV, UNAIDS and the WHO HIV and TB departments are joining forces to encourage a coordinated and concerted global effort to control TB in people living with HIV.

WHO’s Global Task Force on XDR TB have recently published a report outlining measures needed to urgently combat extensively drug-resistant XDR TB. It follows the announcement by WHO and its partners that US$ 95 million will be required to implement the recommendations in the report, to address the threat of XDR-TB in 2007 in southern Africa. WHO have also released new guidelines on how to improve the diagnosis of TB in people living with HIV.

Links:

Access WHO new guidelines.
Frequently asked questions about Tuberculosis and HIV.

WHO TB
Stop TB partnership
Presentations from the Union meeting on XDR TB can be viewed through the Kaisernetworks link on the Union website.
International Union Against Tuberculosis and Lung Disease