In many high-income countries, even a small number of tuberculosis (TB) diagnoses generates headlines and prompts a rapid public health response. Recent cases in US cities such as Seattle and San Francisco illustrate this: media coverage has focused on the number of children tested after TB was identified in a school.
In sub-Saharan Africa, these situations are viewed differently. Some regions have relatively low levels of TB, but others face substantial challenges. Several countries in East and Southern Africa — including Ethiopia, Kenya, Uganda, Nigeria and South Africa — remain among the world’s high TB-burden settings, with significant variation in drug-resistant TB across and within countries.
In many of these settings, sustained transmission places continuous demands on health systems. Responses focus on large-scale, ongoing disease control rather than isolated events. An estimated 10.7 million people fell ill with TB in 2024 and 1.23 million died — more than from any other infectious disease. TB is the leading killer of people living with HIV and a major cause of deaths linked to drug resistance. Although TB remains a known risk in many parts of the world, in the US it is relatively rare and often perceived as a disease of the past.
Our risk of exposure should not depend on something as arbitrary as where we are born.
This imperative informs my work as a scientist developing a TB vaccine. The goal is to bring high-burden settings — whether affected by drug-resistant or drug-sensitive TB — closer to conditions seen in places such as San Francisco or Seattle, where even a small number of cases is unusual.
TB is strongly associated with poverty. Transmission is facilitated in poorly ventilated, crowded settings such as underground mines, busy workplaces and densely populated urban areas. Undernutrition, often linked to poverty, weakens immune defences and increases the risk of developing TB. The disease also places a heavy financial burden on households when a primary breadwinner becomes ill, compounding economic hardship.
Ethiopia is a high TB-burden country, and I witnessed the disease’s effects firsthand while living and working there as a physician and researcher. I saw how TB affects families and communities, and how it devastates lives. This experience has shaped my career.
The only current TB vaccine, the BCG vaccine, is an important but imperfect tool developed more than a century ago. Studies show that it protects young children from severe forms of TB but offers limited protection against pulmonary TB in adolescents and adults.
Adolescents and adults carry the greatest burden of pulmonary TB and drive transmission. Preventing TB in these groups could help protect people of all ages. Widespread use of an effective vaccine could also reduce drug-resistant TB by lowering the need for antibiotic treatment — a critical step in curbing antimicrobial resistance. The World Health Organization estimates that over 25 years, a vaccine with 50% efficacy in adolescents and adults could save 8.5 million lives, prevent 76 million new TB cases and save $41.5 billion for TB-affected households.
A new vaccine that achieves this could be game-changing. But it will have an effect only if it reaches those who need it most. The measles vaccine offers a clear example. Introduced more than 60 years ago, its success has depended on sustained efforts to ensure widespread use. Although outbreaks still occur, they are far smaller than the epidemics seen before vaccination. Over the past 25 years, measles vaccination is estimated to have prevented about 59 million deaths.
The TB vaccine candidate being evaluated at the Gates Medical Research Institute is one of several in late-phase clinical trials. The TB vaccine pipeline has never shown such promise, bringing us closer to improving outcomes for the communities most affected by the disease. If one of these candidates proves effective, governments, global health organisations and communities must work together to ensure it reaches those who need it most. Broad and equitable access will be critical to reducing the global burden of TB and moving closer to a world free of the disease.
Alemnew Dagnew is head of vaccines and biologics development at the Gates Medical Research Institute, where he leads the clinical development of the M72 tuberculosis vaccine. He holds an MD and an MSc in medical microbiology from Addis Ababa University, and an MSc in vaccinology and pharmaceutical clinical development from a joint programme between Novartis Vaccines and the University of Siena.
TB is strongly associated with poverty. Transmission is facilitated in poorly ventilated, crowded settings such as underground mines, busy workplaces and densely populated urban areas
