LISBON — This year will be the one with the most cases of tuberculosis worldwide in all of history—and the greatest number of deaths due to the disease, Dr. Peter Godfrey-Faussett said at the 12th International Congress on Infectious Diseases.
This is in part because of population growth and because TB rates continue to rise. Nine million people develop active TB each year, more than one-third of them in China and India. Two million die of the disease annually, and 30% of the world's population is latently infected with Mycobacterium tuberculosis, according to Dr. Godfrey-Faussett.
But the news is not all bad. Latest estimates by World Health Organization epidemiologists are that TB rates are actually falling in every region of the world except Africa, noted Dr. Godfrey-Faussett, professor of infectious diseases and international health at the London School of Hygiene and Tropical Medicine.
Within Africa, the highest TB rates occur in countries where the prevalence of HIV is greatest. Traditional Directly Observed Treatment, Short Course (DOTS) programs alone will be insufficient to reduce the burden of TB in areas where the epidemic is driven by HIV, he added at the congress, which was sponsored by the International Society for Infectious Diseases.
Structured DOTS programs have been invaluable in combating TB and have cured more than 10 million people since 1994. And in a famous field study in which Chinese health authorities implemented DOTS in half the country, the prevalence of TB plummeted by 37% in a decade, compared with the rate in the other half of China.
Earlier this year at the World Economic Forum annual meeting in Davos, Switzerland, leaders of the Stop TB Partnership, including Bill Gates and Nigerian President Olusegun Obasanjo, launched a new TB strategy that builds upon traditional DOTS. The strategy puts a much greater emphasis on HIV, multidrug-resistant TB, and strengthening health systems in developing nations. It also addresses stigma, a big factor in keeping Africans with TB and HIV from seeking treatment, according to Dr. Godfrey-Faussett. Stigma is a particular problem among health care workers in many African clinics, where pay is often poor and morale low.
The new Stop TB Partnership program, which dovetails with WHO's Global Plan to Stop TB 2006–2015, also calls for more intensive case-finding than has been traditional in DOTS programs. “Nobody is suggesting that we get rid of DOTS. But DOTS is much more than watching people swallow pills,” he stressed.
“Ultimately we may reach the stage where we do active case finding in whole populations,” Dr. Godfrey-Faussett predicted. “Some of the township areas in South Africa and Zambia that we're working in have rates of TB that are no longer measured in cases per 100,000, but in percent. You'll get 1% or 2% of the population per year developing TB. In traditional terms, that's 1,000 or 2,000 per 100,000. When you get rates like that, it becomes possible to think about door-to-door active case finding, but we need to have better diagnostic modalities for that. We badly need new technology. I believe improved diagnosis is the single thing that will make the most difference for TB control.”
Dr. Godfrey-Faussett was somewhat skeptical about the TB vaccines now going into field studies. “There's quite a lot of basic understanding needed before we're likely to have vaccines that work. A lot of people aren't that optimistic that the vaccines now going to trials will really prevent a lot of TB. We still have a lot of work to do in terms of better understanding of the immunology and host-pathogen relationships in TB.”
'We badly need new technology. … Improved diagnosis is the single thing that will make the most difference.' DR. GODFREY-FAUSSETT