How To Win The War Against TB?
Humans have been battling tuberculosis (TB) since the Stone Age. But only in the last century has real progress been made against the disease. A vaccine, first used in humans in 1921, is still in use around the world today. And a series of antibiotics, beginning with streptomycin in the 1940s, has proven effective in treating infections.
Since 1990, TB’s annual death toll has been cut nearly in half. From 2000 to 2014, better diagnosis and treatment saved some 43 million lives. Nonetheless, progress has slowed to a crawl, suggesting that the battle is far from over. TB treatment averted 49 million deaths globally between 2000 and 2015, but diagnostic and treatment gaps persist. In 2015, 6.1 million new TB cases were notified to national authorities and reported to the World Health Organization (WHO). Notified TB cases increased from 2013 to 2015, mostly due to a 34% increase in notifications in India. TB causes the highest number of deaths from a single infectious agent (higher than HIV/AIDS or malaria).
Given the enormous economic burden and widespread human suffering caused by TB, a comprehensive effort to tackle the disease is urgently needed. Professor Salmaan Keshavjee, from Harvard Medical School and a group of TB scientists, clinicians, and advocates from governmental and nongovernmental organizations, hospitals, and universities outlined the measures needed to reach the goal of bringing TB’s death toll to zero.
The first step is to ramp up data-collection efforts. TB epidemics, like those of other infectious diseases, vary by geography; as result, eradication efforts need to be customized to local conditions. Local TB programs need to make better use of existing data, expand routine collection, modernize data-storage systems, and develop the analytical infrastructure needed to measure the effects of local interventions. These findings need to be made available within the country where data were collected, and the lessons learned must be shared with neighboring countries and regions.
Secondly, health-care workers must expand efforts to prevent new infections and quickly treat fresh cases. By actively seeking out victims and treating them quickly, so that they are no longer infectious, the chain of TB transmission can be broken. This strategy has been proven effective by empirical evaluation and mathematical modeling.
Thirdly, efforts must be made to control the seedbeds of the disease, the latent infections that are the source of virtually all new cases of active TB. Mycobacterium tuberculosis, the bacteria that causes the disease, can lay dormant for long periods, during which the victim shows no symptoms of having been infected. Targeting TB at this stage would stop the bacteria’s spread and reduce the disease’s global burden. Rolling out preventive therapies in at-risk populations and developing better diagnostic tests to identify those with asymptomatic infections would help drain reservoirs of the bacteria.
Developing a more effective vaccine would have the biggest impact on the epidemic. The Bacillus Calmette–Guérin vaccine, that is almost 100 years old, is given to infants in many parts of the world, but its efficacy against pulmonary TB is highly variable. To eliminate the disease globally, a better vaccine that protects teens and adults (who are most likely to develop and spread TB) is crucial.
Finally, any effort to eradicate TB must acknowledge that the disease is rooted in poverty and social exclusion. Since the middle of the twentieth century, worldwide efforts to address TB have emphasized biomedical solutions and focused on treating outbreaks. But, before the development of antibiotics, improvements in living standards had helped reduce the impact of TB. Integrating a biomedical approach with an emphasis on the importance of good nutrition, decent housing, and human welfare will be necessary if the disease is to be brought to heel.
TB is an airborne disease — when people infected with TB sneeze, cough, laugh, sing, or talk, the bacteria can be spread into the air and infect another. TB is a threat and we need to see it for what it is.
The global community must work together and translate existing knowledge and strategies into effective programmatic interventions in communities most afflicted by TB. By developing new tools — including rapid diagnostics, safe and shorter treatment of TB infection and disease, and an efficacious TB vaccine — strengthening health systems, and improving the living conditions of at-risk populations, we can neutralize one of humankind’s oldest killers. Only then will we be able to consign TB, at long last, to the history books.
Originally published at www.project-syndicate.org
