Tuberculosis deaths, new infections, and cases have declined since 2000 according to a recent Global Burden of Disease (GBD) study published in The Lancet.
Despite this progress, major challenges remain: there were an estimated 11.9 million cases of tuberculosis (TB) worldwide in 2013, including those individuals with HIV (11.2 million excluding those with HIV); more effective vaccines against the disease are badly needed; and multidrug resistant TB is a growing threat.
No country is immune from the threat of TB. Some health experts estimate that as many as one of every three people on Earth carry the infection, in a dormant or latent state. The point is: TB is everywhere.
This week, 25-year-old Eduardo Rosas Cruz was arrested in California for refusing treatment for the disease. Authorities fear that Cruz could have a multidrug-resistant strain of TB, which is a problem in the area of Mexico he comes from.
Globally, 160 out of every 100,000 people had TB in 2013. While the number of individuals with the disease is large today, cases per 100,000 people (prevalence rate) fell at an annualized rate of 1.3% per year between 2000 and 2013. This is a marked contrast from the period 1990 to 2000, where TB cases per 100,000 rose at a rate of 0.4% per year.
The snapshot from the data visualization tool below shows how global prevalence of TB has changed over time.
Note: the green shading surrounding the line represents the range of possible estimates of TB cases per 100,000 in a given year, also known as the uncertainty interval.
Declines in prevalence worldwide between 2000 and 2013 were largely driven by two regions: East and South Asia. In 2013, South Asia alone accounted for 48% of all tuberculosis deaths in the world.
Certain subgroups of the population are disproportionately affected by TB. At the global level, most tuberculosis deaths among people who are HIV negative are concentrated in men and older age groups, as shown in the figure below from the Lancet study.
Tuberculosis deaths in HIV-negative individuals by age group and sex, 2013
Source: Murray, CJL, Ortblad, KF, Guinovart, C et al. Global, regional, and national incidence and mortality for HIV, tuberculosis, and malaria during 1990—2013: a systematic analysis for the Global Burden of Disease Study 2013. Lancet (2014) published online July 23. http://dx.doi.org/10.1016/S0140-6736(14)60844-8
Drilling down to the country level, the largest number of deaths from TB occur in heavily populated countries: India, Indonesia, China, Pakistan, the Democratic Republic of the Congo, Ethiopia, and Nigeria (see screen grab).
Number of tuberculosis deaths, 2013
Adjusting for differences in population size across countries reveals that countries in sub-Saharan Africa have the highest levels of deaths from tuberculosis in the world, as shown in the screen grab below (Lesotho, Somalia, Burundi, Namibia, and the Central African Republic).
Tuberculosis deaths per 100,000, 2013
Compared to development assistance for HIV, donors have invested substantially less to fight TB in developing countries. From 2000 and 2011, all donors spent $8.3 billion on TB in low- and middle-income countries compared to $51.6 billion on HIV/AIDS (see screen grab). Development assistance for TB compared to HIV/AIDS is associated with larger declines in incidence, prevalence, and death rates.
Development assistance for health for different health focus areas, 1990-2011
While this progress is encouraging, there are still huge challenges. As the world’s population ages, it’s natural that cases and deaths from the disease will increase unless the global health community intervenes. Also, the study’s authors note that, under the right circumstances, studies have shown that multidrug-resistant TB has the potential to undermine the gains that have been made in the fight against tuberculosis.
It’s inspiring to see the strides the world has made in reducing the burden of TB. Another cause for hope are recent advancements in an affordable and fast diagnostic test for the disease, described in a recent Humanosphere article by Tom Murphy. At the same time, the global health community still has a long road ahead in fighting this deadly threat.
Katie Leach-Kemon, a weekly contributor of global health visual information posts for Humanosphere, is a policy translation specialist from the University of Washington’s Institute for Health Metrics and Evaluation.