698 - Why Tuberculosis, an Ancient Disease, Remains a Public Health Threat

Welcome to Public Health On-Call, a podcast from the Johns Hopkins Bloomberg School of Public Health, where we bring evidence, experience, and perspective to make sense of today's leading health challenges. If you have questions or ideas for us, please send an email to [email protected]. That's Public Health [email protected] for future podcast episodes. This is Enzismith Rogers. Today, we visit with an old foe tuberculosis. Dr. Richard Chasin, the Director of the Center for Tuberculosis Research at Johns Hopkins, speaks with Dr. Josh Sharfstein about this mycobacterium that still kills more than a million people a year. Now, there's a global strategy to make historic progress. Let's listen. Dr. Richard Chasin, thank you so much for joining me in Public Health On-Call to talk about tuberculosis. A disease that's been around for a very long time and remains a public health threat. Thanks for having me. Happy to talk with you about tuberculosis. As we say, it's a disease that's been around for a very long time. It's a major continuing public health threat. It's estimated that over the course of history, tuberculosis has killed more than a billion people, just orders of magnitude more than any other infectious disease, including malaria, smallpox, influenza. It's a major public health problem. Prior to the COVID pandemic, it was the leading infectious cause of death, and it is once again emerging as the leading infectious cause of death in the world. Despite the fact that here in the United States, it's declined to the lowest levels in our history, but it remains a big global problem. And it's tuberculosis, but it's tuberculosis that continues to evolve, develop drug resistance, and threaten in new ways, is that fair to say? Yeah, tuberculosis has been with us for a long time, but over the course of the past several decades, really throughout the antibiotic era, the emergence of drug resistance has been a problem. But over the past several decades, we've seen large numbers of people who develop multi-drug resistant tuberculosis, which is much more difficult to treat. Even today, it's estimated that the majority of people who develop multi-drug resistant tuberculosis don't get effectively treated for it, and therefore the mortality is very high. Nevertheless, there's still a lot of drug susceptible tuberculosis out there, and it still kills over a million and a half people per year. Now, many people are aware that tuberculosis can present as a lung disease, and sort of the typical picture we might have, or somebody coughing, coughing, coughing with tuberculosis. We're not going to dwell on this, but it would be fair to say that that is just one way that tuberculosis can kill you. Yeah, tuberculosis can affect almost any organ in the body, or probably every organ in the body, but most commonly it affects the lungs, and that's certainly how it's transmitted. The most lethal form of tuberculosis is meningitis, tuberculosis of the brain and spinal cord, and that's a devastating disease, particularly in children who are more susceptible to it. So, we still see many children throughout the world who develop TB, meningitis, it can kill them, but it can leave them with permanent neurologic damage, even if it's diagnosed and treated. It can affect many parts of the body. You mentioned that the United States has actually seen substantial declines in tuberculosis. I wasn't that long ago. I mean, I guess historically speaking, maybe 100 years ago, that there were TB hospitals all over the country. What has been the key to controlling tuberculosis in the United States? Yeah, in the 1950s and early 60s, the hundreds of TB hospitals around the country all went out of business because of the development of antibiotics. In the United States, I would say that our success in reducing rates of tuberculosis come from an effective public health response. Health departments have generally done a very good job of diagnosing, treating, and following up on contacts of tuberculosis patients. So, we have very effective treatment. We have very effective preventive treatment. When someone has tuberculosis, they can transmit it to others and a standard procedure in the United States for over 50 years has been to identify people in a household who've been exposed to TB and give them preventive therapy. And that's something that's not done in most parts of the world and something that's been very important to our success here. We had an outbreak of multi-drug-resistant TB in the early 1990s that was concentrated in New York City and New Jersey in particular, which was related to the HIV epidemic, but was also a public health failure because the public health system in New York City back in the late 1980s sort of went into disrepair and didn't do a very good job with TB treatment and became overwhelmed with this. There was a strong response from our political leaders and the Congress committed large amounts of funding to strengthen the TB control system in the United States and that has paid off with a big reduction in our rates of TB in the US. Currently in the US, over 70% of the TB that does occur occurs in people who probably were infected with TB somewhere else and another part of the world, people who migrated here or even people who are visiting here who come from countries with higher rates of TB. So most of our TB is important now, whereas previously most of our TB was homegrown. You're really talking about something that we probably should cover more on this podcast in general, which is some of the successes of public health in the United States that this is not something that is just handled by doctors when people show up coughing. This is something that the public health department has to go out, find the cases, treat people preventively who are exposed and make sure the people who are getting treated really finish their treatment that they're on the right medications. And when you do that and you do that at scale, you really can control a vicious disease like tuberculosis. Yeah, I think our public health system, despite all of its challenges, despite all of its constant underfunding, in this regard has really done a remarkable job over the last several decades of controlling the disease. Let me ask you about other parts of the world, where this kind of response has not been possible. What needs to happen to bring TB under control so it is not killing a million and a half people a year, like you said, how do you think about that? I understand you've been part of an effort to try to lay out a strategy. Yeah, so I've worked with the Lancet Commission on tuberculosis, which was established five years ago to try to sort of shake the world into recognizing the severity of the problem and health generator response. We are not alone in that effort. The United Nations has held now two high-level meetings as part of its general assembly, the most recently in September of this year, to try to address TB, the World Health Organization and the UN's stop TB partnership all are involved in trying to generate a global response. But what needs to happen is that the world needs a comprehensive approach to controlling TB. For many years, until just maybe 10 years ago, the global response to controlling TB was to just treat people if they happen to get diagnosed. The ambitions of the world were to try to treat most people at TB. That was about it. Now there's a recognition that there needs to be a much more epidemiologically-based comprehensive approach. You have to actively find the people with TB because they transmit it in their communities and they can die of it if they're not detected and treated. You have to treat TB effectively and the drug-resistant TB has been very difficult to treat in the past. There's been great progress in the last five years alone with new drugs for drug-resistant TB that have completely transformed the treatment of that condition. And now we have to get those treatments to the people who need it. And then very importantly, we have to prevent TB. We have to prevent it in the people who are most likely to get it. And that's people who have been in contact with a person with TB, the contacts of cases, people with HIV infection and other immune deficiencies. And people in facilities like prisons where there's transmission that's sort of uncontrolled. So a comprehensive approach is what's needed. It takes a lot of money to do that. Most TB control is paid for by individual countries. It's not paid for by the World Health Organization. It's not paid for by the US government. It's not paid for by the Gates Foundation. It's paid for by country ministries of health. And they're underfunded. And so most countries don't have a comprehensive approach. They just have a limited approach, which is they just try to treat the people who happen to get diagnosed. That's a medical approach maybe in countries that may not have the strongest medical systems. But even in countries with a strong medical system, that's not a recipe for controlling tuberculosis. That's correct. The countries that have the highest burden of tuberculosis are countries like India, Indonesia, China, countries with very large populations, and varying types of health care systems. I mean, you can get some of the best health care in the world in India and you can get some of the worst health care in the world in India. And India is one country that has a gigantic burden of TB and is trying to develop comprehensive approaches to its control. But there are a lot of challenges. Other countries with high rates of TB are in sub-Saharan Africa where the populations are smaller, but because of the HIV, co-epidemic rates of TB are much, much higher than they are in other countries. So South Africa, for example, has a rate of TB amongst its population that's two to three times as high as India's. It has a much smaller population, but very high rates within that population. Have you or the groups that you've worked with tried to estimate what amount of money it would take to really help the world dramatically lower the burden of tuberculosis? Yeah, the Lancet Commission and the UN high level meeting both came out with estimates of what would be required. The amount of money that's required to strengthen the health care systems in the countries where TB is the biggest problem, globally we're talking about 13 billion dollars a year that needs to go into tuberculosis care. And there needs to be more investment in TB treatment. One of our legends at Johns Hopkins, DA Henderson once told us that with the smallpox eradication campaign, there was research going on right up until the final case was diagnosed and the disease was declared eradicated. That research was very important. And that's true in tuberculosis. Research is important because we obviously haven't got it figured out. We haven't got it controlled yet. So we just have to keep developing better methods so that we can control it. So we need new and better vaccine. We need new and better drugs. We need new and better diagnostic tests. And very importantly, we need to understand how to use them better because a lot of the problem is in the implementation of technology rather than just inventing the technology. So there's a need for both money to care for and provide preventive services. And there's a need for money to conduct research to improve our tools and get them delivered. Very much appreciate those points and the work that you're doing. But before I go, I have to ask you to read out loud what the logo on your sweatshirt says. The logo on my sweatshirt says zero TB. It's a logo for an organization that we have called the zero TB and Tibetan kids project. I have been working with the Tibetan community in India amongst refugees who have suffered very high rates of tuberculosis historically, including in children and the rates of TB and Tibetan children in exile is extraordinarily high. And so we've put together a program working with partners from the Central Tibetan Administration in Darmsala, India, with the blessing of his holiness, the Dalai Lama, working with the schools. And we've reduced the rates of TB by 90% in Tibetan school children through a comprehensive approach of diagnosing the TB that's out there treating those children and giving preventive treatment to the children who've been exposed. And it's been a very effective approach. And we have a nice logo to go with it. It is a pretty great logo and it's an unbelievable program. I can just pause for a moment to imagine the amount of misery and suffering that you collectively have prevented. So Dr. Jason, thanks for explaining that to me and thanks so much for joining me on Public Health on Call. My pleasure. Thank you. Public Health on Call is a podcast from the Johns Hopkins Bloomberg School of Public Health produced by Joshua Sharfstein, Lindsay Smith Rogers, and Stephanie Desmond. Audio production by J.B. Arbagast, Holly Cardinal, Philip Porter, Spencer Greer, and Matthew Martin with support from Chip Hickey. Distribution by Nick Moran, production support from Catherine Ricardo, social media run by Grace Fernandez and Shian Briscoe. That's public health question at jhu.edu for future podcast episodes. Thank you for listening.