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TB Update Highlights Modest Progress, New Opportunities, and Staggering Challenges
17 October 2012 4:30 pm
Tuberculosis (TB) continues to cause an "enormous" burden of disease, according to an update issued today by the World Health Organization (WHO), which estimates that there were 8.7 million new cases in 2011 and 1.4 million deaths. But there are high hopes that improved diagnostics and drugs will, in the next few years, make a major dent in finding people who have the disease, delivering the appropriate treatments to save their lives, and slowing the spread of Mycobacterium tuberculosis itself.
The figures in WHO's Global Tuberculosis Report 2012 are similar to those issued the year before. "TB care and control are at the crossroads," said Mario Raviglione, who heads WHO's STOP TB program, at a press conference held in Washington, D.C. "On the one hand, we have existing as well as new tools on the horizon, which could make a significant difference and even support dreams of elimination in some settings. But on the other hand, we are at the risk of stagnation if additional resources are not urgently mobilized by the governments of endemic countries first and if the international community then is not ready to fill the gaps."
The new, 272-page report emphasizes that much progress was made against TB between 1995 and 2011, during which time 51 million people received a full course of treatment-which lasts a minimum of 6 months-and 20 million lives were saved. But multidrug-resistant (MDR) TB remains a staggering problem, with 630,000 cases worldwide; only one in five of those people receives a proper diagnosis required for effective treatment.
Estimates of new cases fell by 100,000, which, even when accounting for population growth, is a modest 2.2% drop between 2010 and 2011. The proportion of people with TB who are co-infected with HIV globally remains unchanged at 13%, but it exceeds more than 50% in several sub-Saharan African countries. What's clearly new in this year's report, Raviglione said, is the first estimate ever done of the TB burden in children: half a million developed TB in 2011 and 64,000 died from the disease.
The report does highlight some improvements. Many countries have begun to use a new diagnostic, a machine called GeneXpert, that has much higher accuracy than the century-old microscopy test that's widely used and requires far less labor. The 2-hour GeneXpert test can also determine whether a person has MDR TB; previously it took several weeks to culture M. tuberculosis and then test the bacilli for drug sensitivity. But the Xpert test is considerably more expensive: In South Africa in 2011, the government paid at least $15 for each machine test, versus $3 for a sputum microscopy test.
As the report notes, the company that makes GeneXpert, Cepheid of Sunnyvale, California, in August agreed to sell the cartridge the machine uses-which performs the polymerase chain reaction on sputum samples-at a 41% discount to hard-hit and resource-constrained countries. As of June 2012, 67 countries had purchased the discounted system.
The report also emphasizes that for the first time in decades, two new TB drugs are about to come to market. The drugs, which are expected to receive regulatory approval in the next few months, will at first be used to treat MDR and promise to have less toxicity and work more quickly than the treatments now in use. A short-course regimen to cure regular TB and a vaccine that can reliably prevent most cases of the disease still remain years away -- although attempts to make these longheld dreams become reality have intensified.
One particularly sobering chapter of the report focuses on funding for prevention, care, and control, which is projected to total $4.8 billion in 2013 for the 104 countries that have 94% of the cases. But these low- and middle-income countries will need as much as $3 billion more each year to effectively address their TB epidemics. "We are facing in fact major financial risks in a scenario where effective technologies are becoming available," Raviglione stressed. Although he acknowledged that major increases in funding have come from governments and multinational organizations such as The Global Fund to Fight AIDS, Tuberculosis and Malaria, the financial shortfall "will mean millions of unnecessary gaps in the next few years." "History teaches that in the fight against tuberculosis, perceiving the achievements that we have had so far as 'job done' is an absolutely fatal mistake."