In the final session of the workshop, Salmaan Keshavjee, Harvard Medical School, presented his views on what will be required to achieve zero deaths from TB. His talk revisited many of the topics discussed during the workshop and provides a useful look back on the meeting.
Rates of HIV infection and deaths from AIDS have dropped markedly in recent years, as have deaths from malaria. During this same period, however, death rates for TB have been nearly static, declining only about 1 percent per year. The only reason TB mortality may appear to be declining is that HIV-infected patients dying from TB are sometimes classified as “non-TB deaths.” This is a classification artifact and does not represent the true impact of the disease or the unmet need for treatment, said Keshavjee, who noted that, although effective treatment regimens for TB have been available since the early 1950s, 1.5 million to 2 million people still die annually from the disease. “Overall, we have not been successful with the tools that we have been using,” said Keshavjee.
The reason for this lack of success is that optimal biomedical approaches and delivery systems have not been used to attack the disease. The DOTS approach, for example, is a minimalist, not an optimized strategy. Although it has saved millions of lives by standardizing treatment for TB, it was never designed to address drug resistance, a phenomenon that has existed since the use of the first anti-TB drugs. According to Keshavjee, “years of advocating an approach that overlooked resistant strains was a mistake.” DOTS, which requires having a regular supply of high-quality drugs, has had great benefits, but the program also has several limitations:
• It lacks integration with country procurement systems.
• It includes neither SLDs nor drugs for adverse events.
• The DOTS strategy does not include active case detection and relies on patients appearing when they are sick.
• The program has no strategy for latent disease, despite research showing that treatment of latent disease yields mortality and transmission benefits.
• A sole focus on short-course chemotherapy as a panacea has curtailed the development of appropriate adjunct therapies, such as surgery, for patients with advanced disease.
Diagnosis with sputum smear microscopy also has been suboptimal for patients with smear-negative or extrapulmonary TB. It has low sensitivity in patients with paucibacillary disease, such as pediatric populations or people infected with HIV, and is incapable of identifying resistant strains.