By Alemnew Dagnew
Tuberculosis (TB) should not depend on where a person is born, as the global burden of the disease remains heavily shaped by inequality.
In high-income countries, even a small number of tuberculosis (TB) cases can trigger headlines and swift public health action. Recent incidents in cities such as Seattle and San Francisco have drawn attention after children were tested following confirmed cases in schools.
In sub-Saharan Africa, however, the situation is very different. While some regions report relatively low levels of TB, others face a sustained and heavy burden. Countries in East and Southern Africa, including Ethiopia, Kenya, Uganda, Nigeria, and South Africa, remain among those most affected globally. Levels of drug-resistant TB also vary widely across and within these countries.
In many of these settings, transmission is ongoing and places constant pressure on health systems. The response is therefore focused on large-scale disease control rather than isolated outbreaks.
Globally, an estimated 10.7 million people fell ill with TB in 2024, and 1.23 million died, making TB the deadliest infectious disease worldwide. It is also the leading cause of death among people living with HIV and a major contributor to deaths linked to antimicrobial resistance.
Despite this, TB is relatively rare in countries such as the United States and is often viewed as a disease of the past.
The risk of exposure remains uneven across the world, shaped by geography and socioeconomic conditions rather than chance.
Efforts to develop a new TB vaccine are driven by the goal of reducing high-burden settings to levels seen in cities such as San Francisco or Seattle, where even a small number of cases is considered unusual.
TB is closely linked to poverty. It spreads more easily in poorly ventilated and overcrowded environments such as mines, congested workplaces, and densely populated urban settlements. Undernutrition, which weakens the immune system, increases the risk of disease.
The economic impact can also be severe. When a household’s main earner falls ill, families often face significant financial strain, deepening poverty.
Experience from high-burden countries such as Ethiopia shows the devastating effects of TB on families and communities, and underscores the urgency of finding more effective solutions.
The only widely used vaccine, Bacillus Calmette–Guérin (BCG), is more than 100 years old. While it offers protection to young children against severe forms of TB, studies show it provides limited protection against pulmonary TB in adolescents and adults.
These older age groups bear the highest disease burden and are the primary drivers of transmission. Preventing TB in adolescents and adults would therefore have a broader public health impact.
A more effective vaccine could also help reduce drug-resistant TB by lowering the need for antibiotic treatment.
The World Health Organization estimates that over 25 years, a vaccine with 50% efficacy for adolescents and adults could save 8.5 million lives, prevent 76 million new cases, and save households about $41.5bn.
A new vaccine could be transformative, but only if it is widely accessible to those most at risk.
The experience of the measles vaccine shows how sustained immunisation efforts can dramatically reduce disease. Although outbreaks still occur, they are far smaller than before vaccination programmes were introduced. Over the past 25 years, measles vaccination has prevented an estimated 59 million deaths.
Several TB vaccine candidates are now in late-stage clinical trials, including one being evaluated by the Gates Medical Research Institute.
This progress marks a significant moment in the fight against TB, but success will depend on collaboration between governments, global health organisations, and communities.
Broad and equitable access will be critical to reducing the global burden of TB and moving closer to eliminating the disease.
Alemnew Dagnew, M.D., is Head of Vaccines & Biologics Development at the Gates Medical Research Institute (Gates MRI), where he leads the clinical development of the M72 tuberculosis vaccine.
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