Hope for a more reasoned U.S. approach to global TB

April 16, 2015

By: Talia Dubovi and Phillip Nieburg

The annual global numbers of TB disease cases and TB deaths have been falling slowly since the 1990s. The numbers of U.S. residents newly diagnosed with TB disease every year have also been falling over the same period.  In effect, successful TB treatment has saved millions of lives over that period. 

But that progress should not be taken as a justification for reducing U.S. investments in global TB control, as has been suggested by the Obama administration in its budget requests to Congress over the last several years, including in the current cycle.  Here are six of the many reasons why global TB remains a major problem, and why continued U.S. engagement is more important than ever:

1. First, 1.5 million people still die of TB every year and many others, although cured, are left with life-long breathing disabilities. And the other costs are significant: the family of the average TB patient spends more than half of its total annual household income on the diagnosis and treatment of TB.  

2. In addition, two billion people in the world are estimated to have latent TB infections, the initial stage of TB in which the infection is walled off and is not contagious, held in check by the body’s immune system.  Many of these latent TB infections will ultimately progress to active TB disease if preventive drug treatment is not given in time.

3. TB is the largest single cause of death among AIDS patients, responsible for at least one quarter of all AIDS deaths. We say “at least one quarter” because that estimate may be a serious underestimate of the true burden.  In fact, recent autopsy studies have consistently found that more than half of people dying of AIDS – including those taking anti-retroviral drug treatment for their HIV infection – have widespread TB infections in their organs. Thus, protecting, even extending, the tremendous life-saving benefits conferred by the President’s Emergency Plan for AIDS Relief (PEPFAR) will ultimately depend on better control of global TB. 

4. Another recently identified and highly troubling aspect of TB disease is its link to diabetes. People with diabetes – and even those people who have the kind of mild blood sugar abnormalities found in “pre-diabetes” – run a much greater risk of developing active TB disease.  The projected rapid increase in numbers of people in the world with diabetes is likely to lead to an increase in numbers of people whose latent TB infection progresses to active TB disease.

5. TB is also closely linked to maternal and child health (MCH) issues. Most of the 530,000 women who died of TB in 2013 were women of child-bearing age. TB is known to be a major non-obstetric cause of maternal mortality. And the problem is not just for the women themselves: a recent South African study found that 15 percent of mothers with TB infected their infants with the disease in the first three weeks of life, an age group in which both the diagnosis and treatment of TB are exceedingly difficult. Even beyond the neonatal period, data suggests that most TB cases in children are misdiagnosed and that the most recent (2013) figure of 550,000 new pediatric TB cases annually is likely to be an underestimate. In fact, TB expert Jeffrey Starke has pointed out the unfortunate absence of concern about – or advocacy for – TB control within the child survival movement.      

6. As if these linkages between TB and other health burdens were not enough, the last 20 years has seen the emergence of multi-drug-resistant TB (MDR-TB) bacteria. These MDR-TBs are variants of TB bacteria with DNA that has mutated to the point that they cannot be killed by the usual TB drugs. Initially, much of the spread of MDR-TB was caused by people not receiving – or not taking – the right set of four TB drugs for the 6-9 months required for cure. However, recent data clearly shows that MDR-TB is now being spread from person-to person. The rate of increase in the global numbers of MDR-TB cases is still uncertain, but what is certain is that a large proportion of the world’s MDR-TB cases are not receiving the proper care they need.

These six examples are not the only TB challenges facing the global health community, which include gaps in testing and diagnostic tools, as well as the need for new treatment options. But these examples throw into stark relief the irony of recent administration proposals to reduce U.S. funding for global TB programs. The links between TB on one hand and HIV, diabetes, and MCH on the other hand mean that these funding cuts not only threaten global efforts against TB – the second largest infectious killer of adults worldwide – but also impact other important strategic U.S. priorities.

Finally, decreasing numbers of a highly infectious disease do not automatically mean that the disease has been controlled or that program budget reductions should follow.  Initial declines in disease numbers often means that the easiest-to-find and easiest-to-treat cases have been identified and are being treated, while the hardest cases remain unidentified or untreated because of geographic, societal, and/or programmatic obstacles. Allowing these underlying factors to remain unaddressed is an open invitation for eventual disease resurgence. Thus, later stages of disease control programs for TB require ongoing commitment and resources to achieve results and prevent backsliding.     

All these points together were a large part of our motivation for creating our new TB primer, Tuberculosis – A Complex Health Threat.  Our goal was to provide a clear explanation of the real threats and burdens of global TB to enable U.S. policy-makers to make informed and reasoned choices about funding and other resources for control of this important global disease.