The following is a guest post from the U.S. Centers for Disease Control and Prevention Division of Global HIV and TB, with answers to questions on the global tuberculosis pandemic and responses from Division Director Shannon Hader.
- TB is one of the world’s oldest diseases, yet it continues to kill millions of people each year. Why has it remained a persistent threat?
That’s a good question. TB is preventable, treatable, and curable — we’ve had a cure since the 1940s. The World Health Organization declared TB a global health emergency in 1993. And yet today, TB persists: 2 billion people — a third of the world’s population — are infected with TB, there are nearly 10 million active cases each year, and 1.5 million deaths. In fact, TB ranks alongside HIV as the leading cause of death from infectious disease worldwide.
The problem is this: TB is an airborne infectious disease that spreads and thrives under conditions that affect the poorest and most marginalized in our society, those who are often without a strong political voice to demand better results. It spreads easily in crowded environments without adequate ventilation or infection control measures in place. Young children and people with poor nutritional status, HIV, and other complicating illnesses are at greater risk of becoming ill from TB, and poor access to quality health services create barriers to their timely diagnosis and successful treatment.
WHO estimates that we still haven’t found a third of the people with active TB in order to get them into care and onto treatment, and untreated TB patients drive ongoing transmission in their communities. While we have several medications to treat patients who we know have TB, currently available regimens can be difficult to take successfully: they require multiple pills a day for multiple months, with potentially unpleasant side effects. In addition, incomplete or incorrect courses of treatment select for bacterial resistance, leading to strains known as multi-drug-resistant (MDR) or extensively drug resistant (XDR) TB. MDR and XDR TB are increasingly taking human and economic tolls around the world and threaten the utility of our existing drug regimens and global health security as a whole.
- In the wake of last year’s WHO TB report showing TB ranks alongside HIV/AIDS as the world’s top infectious disease killer, what do you see as most urgently needed to turn the tide on this epidemic?
The tools we have today can be optimized to bend the curve of the TB epidemic, but they will not get us fully to our goal of ending the epidemic. We also need innovation — in new diagnostics and new drugs — and a paradigm shift in the way we do business. We are using old drugs that are often toxic and diagnostics that are not delivering the kind of point-of-care rapid test required to more easily link and keep TB patients in care. We still do not have an effective vaccine, more than 125 years after the discovery of the cause of TB. We do have decades of experience successfully fighting other diseases that we can apply to tackling one of the world’s oldest. What we require is the political will to bring the tools and experiences we already have to scale and to invest in the research required to develop new diagnostics, treatments, and prevention methods worthy of a 21st century fight against this disease.
Fighting TB is, and has always been, about basic public health principles: improving the efficiency and effectiveness of the public health workforce, laboratories and diagnostics required to find the disease, the therapies and clinicians equipped to cure it, and the basic sanitation, ventilation, and infection control interventions to prevent it. It will require strong commodity management systems to ensure a consistent supply of drugs, and a healthcare environment that prevents the transmission of TB to healthcare workers and patients. Most importantly, these tools and systems must work, be of high-quality and accessible to those who need them most. These types of interventions are found within the United States government’s Global Health Security Agenda, and are a critical step toward strengthening health systems in many high burden TB countries.
- The latest WHO surveillance report indicates that the numbers of MDR TB cases are relatively small and stable. What is the basis for the urgency around MDR TB?
MDR TB is a serious threat. We saw TB strains that were resistant to one or two drugs emerge in the 1940s, but with each passing year we have identified strains with resistance to more and more drugs, and these are becoming more widespread. MDR TB is now found in every country in the world. Of the 9.6 million cases of TB last year, nearly 500,000 are resistant to our best treatment. Of those resistant to treatment, only 1 in 4 was diagnosed and it is estimated that only 1 in 10 will be cured. Unfortunately, those who are not cured can spread MDR TB to others, and often die or face prolonged and often debilitating illness.
XDR TB — extensively drug-resistant TB, which is resistant to the best first-line and second-line drugs — was first identified in the late 1980s, and by 2005 it was widespread. It has now been reported in more than 100 countries. Of the roughly 2,600 patients diagnosed with XDR TB in 2014, only about a quarter were successfully treated.
In addition to significant morbidity and mortality, MDR TB can have dramatic economic costs at the individual and local level as well as on a macro scale. To cure a single case of XDR TB in the United States costs nearly $500,000, according to a study done by CDC. These costs can bankrupt local public health programs and put other important prevention and treatment programs at risk. By 2050, if left unchecked, it is estimated that MDR TB will cost the global economy $17 trillion due to lost productivity. Upfront investments in TB prevention and control now will mitigate future costs that we simply cannot afford.
In parts of the world where TB is relatively rare, complacency about the risk of TB and MDR TB is a risk. However, given the sheer size of the epidemic, an increasingly mobile global population, and especially in the face of drug resistance, this complacency is dangerous. We saw this in the United States in the 1990s when we let down our guard for TB and, due to the growing AIDS epidemic, TB resurged in several major American cities.
4. What is the CDC doing to scale up its efforts to fight TB around the world?
CDC is driving innovation to end TB as a global public health threat. Our Division of Global HIV and TB has boots on the ground to combat TB in more than 25 countries, directly partnering with Ministries of Health to prevent, find, and cure TB and drug resistant TB.
We’re providing technical support to strengthen surveillance systems, improving laboratory capacity, and aiding in infection control procedures in high burden countries. We are also leading research to optimize tools to diagnose, treat, and prevent TB among some of the most vulnerable populations — specifically, children and people living with HIV. Our scientists are also leading research to support the creation of new, shorter, less toxic TB drug regimens and we’re tackling drug-resistant TB around the world — developing guidelines and global standards for treating the drug-resistant strains and stepping up efforts to prevent multi drug-resistant TB among those co-infected with both HIV and TB.
For example, our current work in India focuses on addressing drug-resistant TB using highly innovative approaches and in Kenya, we are currently leading a clinical trial to identify the best methods to diagnose TB among children. All over the world, we are joining forces with key organizations to maximize impact in the fight against TB.
- About a year ago, the CDC aligned its global HIV and TB portfolios under one Division – which you lead. What was the motivation behind this? What can be gained by tackling these two epidemics in tandem?
The motivation was fairly simple — bringing most of our global TB experts into a single team makes us smarter and more efficient, allowing us to promote learning across projects and countries more easily in real time. It also allows us to better leverage our existing footprints combating HIV to tackle the two epidemics in tandem in countries with both high rates of HIV and also high rates of TB.
It’s important to understand the relationship between HIV and TB. TB now ranks alongside HIV/AIDS as the world’s top infectious disease killer, claiming 1.5 million lives each year. The two diseases hide behind stigma and discrimination in some of the world’s most marginalized and vulnerable populations, leading to major barriers in diagnosis and treatment. Co-infection with HIV and TB is also a problem. Tuberculosis can lead to dangerous complications for people living with HIV making it essential that we treat the diseases in tandem. The World Health Organization reported that people living with HIV are from 26 to 31 times more likely to develop TB than people without HIV.
It’s shameful that today, with the great strides made in the global HIV response, that TB — a preventable and curable disease — remains the leading cause of death for people living with HIV in the developing world. Adoption of 2015 WHO HIV Treatment Guidelines, urging treatment for all immediately upon HIV diagnosis, is also a promising strategy to prevent active TB cases among those living with HIV and greatly reduce the overall burden of TB in a country.
CDC is dedicated to seeing an end to both of these diseases. The strategic move to consolidate HIV and TB resources and expertise across the agency will increase our impact for both. In countries with dual epidemics, a tandem response makes sense: progress against one equals progress against the other.
6. What gives you the greatest hope that we can end TB?
What I am personally reassured by is that we may be on the cusp of a paradigm shift in global TB. The world recognizes the threat of TB and MDR TB, and recent viral epidemics such as Ebola, pandemic influenza and Zika have opened new dialogues about global health security and the role of TB prevention and control programs within these. We are at a point of convergence, where increasing political will and attention to this epidemic can drive the innovations we need to end it.
We’ve seen great leadership from the World Health Organization and the Stop TB Partnership in putting out a strategy and an implementation plan that lays out a detailed vision for what is required to End TB by 2035. The plans calls for scaling up what works, but it also calls for specific innovations in diagnostics, drugs, and vaccine development that really could change the game in the fight against TB. In scaling up what works, their plan is essentially a road map, with the nuance and detail required to guide tailored response in each country — to meet them where they are, take into account the realities of their TB epidemic, and target interventions to have the greatest impact.
Ending TB will require greater collaboration and investment from all corners of the global public and global health communities, including civil society, the private sector, and government and international partners. To me, the biggest question that remains is: will we mobilize enough collective will, or will we instead fail to shift, once again allowing this ancient disease to retain its hold on our modern world?
Shannon Hader, MD, MPH is the Director of CDC’s Division of Global HIV and TB. Visit here to learn more about CDC’s efforts to fight global HIV and TB.