Last week, the Global Center released a new issue brief on drug-resistant TB to mark World TB Day. Included in the brief was this interview with Dr. Sarita Shah, who recently presented new research showing that strains of extensively drug-resistant TB (XDR-TB) in Tugela Ferry, South Africa, are becoming more resistant.
Tugela Ferry is ground zero for XDR, where doctors first described this deadly bug in 2005. Soon, 53 patients were diagnosed with XDR-TB; 52 of those patients died within an average of 16 days after they sought medical care. Since those first cases emerged, over 500 patients in Tugela Ferry have been diagnosed with XDR-TB, and cases of this deadly infection have been reported in 58 countries. And because of inadequate treatment, XDR-TB strains have developed resistance to an even greater number of drugs than before. In this Q&A, Dr. Shah, an assistant professor of medicine and of epidemiology and population health at Albert Einstein College of Medicine, describes a global health system that essentially guarantees the continued spread of multidrug-resistant TB (MDR-TB) and XDR-TB and talks about innovative efforts to transform the treatment of drug-resistant TB.
Q: You presented new research at the Union World Conference on Lung Health in 2009 showing that XDR has become more resistant. Why and how is this happening?
A: In July 2005, most of the XDR we analyzed in Tugela Ferry was resistant to four to five drugs. By 2009, 100% of patients in our study had XDR that was resistant to at least 6 drugs—and most to 8 drugs. This is a very worrying trend. But it’s not a surprise that drug resistance is going to increase if we have weak TB programs, not enough support, and not enough attention to this critical issue. This is happening because in many places, MDR is being treated in a completely unsupported, chaotic way. That treatment fails, and then we get XDR. And it’s not surprising that if we don’t treat XDR properly, it’s going to get ever more resistant. We will run out of letters soon, and we’ll be at the end of the road, with no more medicines available.
Q: Can you talk about the lineage of XDR and how it was initially passed along?
A: XDR has been around for a very long time. It was present in South Africa as early as 2001. Now that people are looking for it, we’re finding it everywhere. It isn’t a person spreading it around. It’s the conditions that create XDR, and those are everywhere—weak public health infrastructure and inadequate patient support for completing treatment, plus HIV/AIDS.
Q: Can you describe what’s happening on the ground now in KwaZulu-Natal Province, where you and your colleagues do much of your work on drug-resistant TB?
A: What happens in South Africa—and in many other countries around the world—is there’s a centralized, specialty hospital that treats all patients with MDR-TB, because the drugs used for treatment are complicated, expensive and specialized. So, it is felt that treatment should be by specialists who can use the drugs correctly and monitor for side effects appropriately. In KwaZulu-Natal, this hospital used to be able to admit all MDR patients for six months, during which patients are assured to take their medicines every single day. And then for the remaining year and a half of MDR treatment, the patients are supposed to come back every month for a check-up and more medicines. You can probably imagine that not everyone comes back. They live far away. They’re probably feeling better. They can’t afford to miss a day of work. So what happens? In South Africa, we had an MDR default rate of 15–20% percent, so you’re at XDR.
Starting about four years ago, that referral hospital became completely overwhelmed. They have 160 beds, and we diagnose over 2,500 MDR cases in our province alone per year, so you can see how that math doesn’t work. Since the central hospital couldn’t admit everyone anymore, there were long waiting lists to get into the hospital, which is the only way to get the MDR medicines. Half of the diagnosed cases might die before being admitted. The same thing happens in other places as well—or worse, no MDR treatment is available in the country at all—so it’s important to realize South Africa isn’t unique in this sense. The issue of getting MDR patients access to good drugs in a timely way is a major global effort led by the Green Light Committee.
But let’s say a patient manages to get in to the MDR hospital. The doctors would try to give him or her medicines, but they might discharge the patient after 3 or 4 months because they have to face the daily reality of the long waiting lists of patients who are, literally, dying while waiting to get access to the medicines. So, patients are discharged early—with all the best intentions of trying to get more people into care—but, this is the way you get more resistance and also transmit disease to others.
Q: What’s the fix for this kind of situation that guarantees failed treatment, more transmission, and greater resistance? (more…)