GLOBAL: Simple measures could radically reduce TB

Thursday, November 15, 2007

Better healthcare measures could curb the tide of tuberculosis (TB) and other lung diseases, even with existing drugs and technology. This was the final message from the 38th World Conference on Lung Health, in Cape Town.

At the conclusion of the 4-day meeting this week, Nils Billo, executive director of the International Union against Tuberculosis and Lung Diseases (The Union), said that improving infection control, even using simple and cheap methods, could significantly reduce the spread of tuberculosis (TB) and its death toll, especially among people with HIV.

However, the 3,000 delegates heard that better drugs and vaccines for treating and preventing TB, and faster and more accurate diagnostics were needed if the disease were to be eradicated. Much of the research into finding effective, practical and affordable technologies is being done by not-for-profit partnerships, funded by government, donors and the private sector.

TB has suffered from a lack of attention by policy-makers and funders for decades because the disease was relatively well contained in developed countries. However, an outbreak of TB in New York in the 1990s, combined with the growing toll of TB among people with HIV/AIDS, has been putting the disease on policy and research agendas.

Diagnosing TB can be difficult, especially where healthcare facilities have limited or no access to expensive machinery such as x-ray machines, or laboratories capable of the lengthy culturing of sputum samples to detect the bacillus.

But six promising TB vaccines are being shepherded towards human clinical trials within the next year, but even if one of them proves sufficiently effective, it is unlikely to be available for worldwide use before 2015.

New drugs

The Global Alliance for TB Drug Research announced that it has two new drugs for treating TB in development; one of them, moxifloxacin, is among the most advanced potential new TB drugs, and is about to go into a phase 3 clinical trial involving more than 2000 volunteers in Kenya, South Africa, Tanzania and Zambia.

The organisation hopes its new antibiotic will eventually be used as a substitute for existing medications, and help shorten the current 6-month treatment period with first-line drugs.

Unfortunately, moxifloxacin is not effective against highly drug-resistant forms of TB. The rising number of drug-resistant cases was a focus of this year's Lung Conference, along with the spread of TB among HIV-positive people.

TB cure rates are low worldwide, but particularly in developing countries with high burdens of the disease, often fuelled by HIV/AIDS. In South Africa, successful treatment for TB varies widely across provinces and districts: one district in Mpumalanga Province has reported cure rates of just 12 percent, compared to a national success rate of just under 58 percent, which is already well below the target of 85 percent recommended by the WHO.

Drug-resistant forms of TB have been driven by unsuccessful first-line TB treatment, with many patients failing to complete the 6-month course of medication. Much of the transmission of resistant strains of TB occurs in healthcare settings.

Multidrug-resistant (MDR) TB is resistant to at least two of the most effective and commonly used first-line treatments for the disease, while extensively drug-resistant (XDR) TB is also impervious to at least one of the second-line drugs. Worldwide, it is estimated that four percent of TB infections are resistant to multiple drugs, although the figure is as high as 20 percent in some areas.

More money

The WHO says it needs US$2.15 billion to fully implement its MDR-TB and XDR-TB Response Plan 2007-2008. This could potentially save 134,000 lives over the 2-year period by treating 160,000 people with MDR forms of the disease, and another 16,000 with XDR-TB.

An estimated 14 million people worldwide are co-infected with TB and HIV, while more than two-thirds of people infected with TB in sub-Saharan Africa are also living with HIV/AIDS. The two diseases reinforce each other in the body, each weakening the immune system's defences against the other.

Conference delegates heard of the critical need to co-ordinate action against both diseases, to create an effective response to what some presenters characterised as an epidemic of co-infection. Speakers repeatedly pointed out that the fight against TB has been relatively poorly resourced, compared to the more high-profile HIV/AIDS fight.

On the day the Lung Conference ended, the Global Fund to Fight Aids, TB and Malaria announced US$1.1 billion in new grants, but TB accounted for only 10 percent of funding, compared to 48 percent for HIV/AIDS and 42 percent for malaria.

Among the calls for action at the conference was to make greater use of one of the most effective anti-TB drugs, Isoniazid, (also called isonicotinyl hydrazine, or INH). Research in Brazil found that it could prevent TB infection in HIV-positive patients by up to 75 percent, if used in conjunction with antiretroviral therapy.

But presenters also emphasised the positive impact that better healthcare management could make, including basic steps to prevent the spread of TB in healthcare settings: opening windows, reducing the number of TB patients in a ward, and even simply separating coughing - and therefore potentially infectious TB patients - from others.

The 2008 World Conference on Lung Health will take place in Paris.


Source: PlusNews
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