Explainer

Tuberculosis is curable and preventable – why do millions still die?

Over the last 100 years, tuberculosis research has saved millions of lives but it has failed to curb the epidemic. While some recent scientific developments are promising, progress is slow, and the tuberculosis health crisis is escalating. Here’s what you need to know.

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Patrick Shepherd / Wellcome

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Tuberculosis is curable and preventable – why do millions still die?
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Tuberculosis (TB) is a curable and preventable infectious disease. And yet, 10.6 million people fell ill with tuberculosis and 1.3 million people died from it in 2022.

The only infectious disease to cause more deaths in recent years was Covid-19, in 2021 and 2022.

The two diseases have other similarities too. Tuberculosis is also spread through the air, it mainly affects the lungs, and common symptoms include coughing, fever and fatigue.  However, unlike Covid-19, research into vaccines, treatments and diagnostics for tuberculosis has been neglected for years.  
 
And now, after years of decline, the number of people developing tuberculosis is on the rise.

In this explainer video, featuring Professor Willem Hanekom and Professor Henry Mwandumba, we dive deeper into the reasons behind the current TB health crisis – and what's needed to bring an end to the deadly disease.

Tuberculosis treatments and vaccines are getting left behind 

There is only one licensed vaccine for tuberculosis: the Bacille Calmette-Guérin (BCG) vaccine. 

It was invented over 100 years ago, and while it has saved millions of lives since, it has limitations. The BCG vaccine provides protection against the most severe forms of tuberculosis in children but offers variable and limited protection for adolescents and adults. 

And although tuberculosis is curable with a combination of antibiotics, until recently, the standard course of drugs took six to nine months to complete, and treatment for drug-resistant tuberculosis took up to two years with much lower chances of cure.    

New treatment options have become available in the last ten years to help reduce treatment lengths, remove toxic drugs from regimens and tackle the growing tide of multi-drug-resistant tuberculosis. However, access to these drugs in many of the most deeply affected countries is still challenging.   

Diagnosis rates are also low. Of the 10.6 million people estimated to have developed active tuberculosis in 2022, around 3 million were undiagnosed or unreported. 

Meanwhile, drug-resistant tuberculosis poses a persistent and deadly threat to global health security. In 2022 alone, over 400,000 cases occurred worldwide, with diagnosis and treatment of drug-resistant tuberculosis falling well short of global targets. 

So, despite being declared a global public health emergency 30 years ago, the world still faces high disease prevalence, increasing drug resistance and inadequate resources to limit further spread. 

The pace of tuberculosis innovation has not matched this need – with insufficient political interest and financial investment contributing to the slow progress of research and development.

More research into tuberculosis could save millions of lives 

Developing new tools to tackle this epidemic would save millions of lives. But first, we need to transform research and development for tuberculosis.

Although funding for research into new tuberculosis vaccines, treatments and diagnostic tools has been slowly increasing, it still falls well below the estimated US$5 billion needed every year to reach global targets to end TB by 2030.   

Private sector financing has been persistently low because tuberculosis primarily impacts low- and middle-income countries – accounting for over 80% of all cases. Tuberculosis products are not expected to secure sufficient return on investment, and as a result, industry sources only make up about 10% of the overall investment.

Vaccine development has particularly suffered. While governments spent around $90 billion on research for the Covid-19 vaccine in the first year of the pandemic, the total spent on developing a new tuberculosis vaccine is a fraction of that – just $1.1 billion in the last 11 years [PDF]

Even as newer products have been approved, these have not been equitably available as high prices have limited access to some of the communities that need them most.

After almost 50 years of limited innovation, the last decade has shown the life-saving potential if we can reinvigorate the field and ensure equitable access to new products. 

For example, safer, quicker and more effective oral treatments have replaced painful injectable drugs with toxic side effects, and other new, promising drug candidates are in development. 

There have also been breakthroughs in the development of new tuberculosis vaccines. Like the M72 vaccine candidate, which showed around 50% efficacy results in the phase 2b study and entered phase 3 trials in March 2024. If approved, this could prevent up to 30 million cases by 2050.

Wellcome is supporting the fight against tuberculosis 

Wellcome is investing in tuberculosis research and development, focussing on the countries that are most impacted by the disease.

We want to make sure that new vaccines to tackle all forms of tuberculosis are developed in a way that ensures the products are accessible and affordable to the people who need them most, and with the urgency that the devastating health crisis in these communities demands.

Our infectious disease programme focuses on intervening earlier with better products and tools. Our work in tuberculosis will do just that by transforming the research and development ecosystem to prioritise public health and ensure accessibility and availability for all.