Q&A: Ending tuberculosis

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This transcript has been lightly edited for clarity

What does your research reveal about efforts to meet the 2020 milestones to end tuberculosis?

2020 End TB milestones include a 20% reduction in TB incidence and a 35% reduction in TB deaths compared to 2015 levels.

Despite concerted efforts, the milestones were not met globally, with only a 6% reduction in TB incidence and a 12% reduction in TB deaths achieved. However, the situation is not entirely gloomy. 15 countries met the incidence milestone, and 17 countries met the mortality milestone. The path forward involves learning from these success stories. Examples of promising innovative strategies include active case findings in TB hotspots, enhancing TB diagnostics through partnerships with private laboratories, and implementing patient incentive programs to improve TB treatment outcomes.

Your research reveals differential progress across age groups. Why is that and what can be done?

We’ve seen the largest declines in both the TB incidence and deaths in children under 5 and the slowest declines in older adults. The improvement seen in children under 5 could be attributable to multiple factors such as better access to health care, improvements in child growth outcomes, reductions in mother-to-child transmission of HIV, and the provision of TB preventive treatment to children who are household contacts of TB patients. However, the coverage of TB preventive treatment in children varies widely across countries, so increasing intake, especially in low-coverage areas, could further accelerate progress in this age group.  

In terms of potential reasons for the slow progress in older adults, they tend to have weakened immunity and comorbidities, which increase the risk of TB disease and death. They’re also at high risk of adverse reactions to TB drugs, indicating the need for developing TB treatments that are not only shorter-duration but also less toxic, to better serve this population.

What are the main risk factors for tuberculosis, and how can they be mitigated to reduce incidence of the disease?

The main TB risk factors evaluated in our study include smoking, alcohol consumption, and diabetes. A recommended strategy to mitigate those risks and the associated TB burden, is to integrate TB services with other care services, for example, integrating smoking cessation programs into TB care services, or linking TB and diabetes programs. Studies have shown improved outcomes in integrated programs compared to routine, standalone programs.

How did COVID impact tuberculosis mortality, and do we need to better understand its impact?

The impact of the COVID-19 pandemic on TB can be summarized with two hypotheses and what the available data tell us so far. One hypothesis is that pandemic-related disruptions in TB diagnostic and treatment services have resulted in more TB deaths.

The other hypothesis is that mask wearing and social distancing might help reduce TB transmission, and at the same time, individuals with early-stage TB who got COVID-19 could have become more vulnerable, resulting in more deaths counted under COVID-19, possibly reducing TB deaths. Our analysis of vital registration data in 41 countries showed that many countries reported fewer TB deaths than expected in the absence of the pandemic.

There were also a few countries that reported more TB deaths than expected. Studies conducted in countries including those that reported more TB deaths than expected have shown potential misclassification of COVID-19 deaths as non-COVID respiratory conditions. So, it is possible that COVID-19 deaths were misclassified as TB deaths in those countries. These results call for more data and further investigation to better understand the impact of the pandemic on TB mortality.

How well placed is the global health community to continue the fight against TB?

I’m cautiously optimistic about the world’s ability to fight TB thanks to ongoing efforts and recent achievements. Priorities should include strengthening health systems to close TB detection and treatment gaps, providing TB preventive treatment to individuals at high risk of developing TB, and integrating TB services with other health care services to address risk factors and comorbidities.

A key strategy should be tailoring interventions to fit local contexts. Consider, for instance, the daily realities of individuals living in TB hotspots such as urban slums, where losing a day’s wage to travel for TB care is not an option. Here, mobile TB clinics conveniently located near work or living areas can be a game changer. Such clinics have the potential to not only ensure early detection and treatment to reduce TB transmission in the community, but also better patient follow-up care to enhance treatment success.