A cough that won’t quit. You blame allergies, then a lingering cold, then the dry air. Three weeks later it’s still there, and now you’re waking up drenched in sweat. Most people wouldn’t think twice about the disease behind those symptoms, because they assume it belongs to history books. It doesn’t.
Key Takeaways
- Tuberculosis (TB) is once again the world’s leading cause of death from a single infectious agent, killing an estimated 1.23 million people in 2024, according to the World Health Organization.
- TB overtook COVID-19 again in 2023, after the pandemic pushed it out of the top spot for three years.
- Global cases and deaths dipped slightly in 2024 for the first time since the pandemic, but WHO warns that funding cuts could erase those gains.
- In the U.S., TB is rare, but the CDC estimates up to 13 million people have latent (inactive) TB, and in 2025 cases fell in every age group except adults 65 and older.
- TB is preventable and usually curable. A cough lasting three weeks or more is worth a doctor’s visit.
What the numbers actually show
Every year, WHO publishes a global report tracking tuberculosis. Its most recent edition, released in November 2025 and covering 2024, estimates that 10.7 million people fell ill with TB worldwide and 1.23 million died, including about 150,000 people living with HIV. That’s a small drop from 1.25 million deaths in 2023.
The “leading killer” title is not new either. TB held that spot for years before the pandemic. COVID-19 displaced it from 2020 through 2022, and WHO’s 2024 report concluded that TB had most likely reclaimed first place in 2023. That same year, 8.2 million people were newly diagnosed, the highest number since WHO began global monitoring in 1995.
The burden is concentrated. In 2024, eight countries accounted for about two-thirds of all cases, with India alone making up roughly a quarter of cases and about 28% of deaths.
Why an old disease is still winning
TB is caused by the bacterium Mycobacterium tuberculosis. (Despite the “myco” in its name, which often causes confusion, it is a bacterium, not a fungus.) It spreads through the air when someone with active TB in their lungs coughs, sneezes, or even talks. Left untreated, active TB can be fatal in about half of cases.
Several forces keep it going. The pandemic disrupted diagnosis and treatment worldwide, so many cases were missed. Drug-resistant strains are harder and more expensive to treat, and WHO lists TB as a major contributor to antimicrobial resistance deaths. And WHO identifies five risk factors that drive a large share of new cases: undernutrition, HIV infection, alcohol use disorders, smoking, and diabetes.
Money matters too. WHO has warned that sustained cuts to international donor funding could lead to as many as 2 million additional deaths and 10 million more people falling ill between 2025 and 2035.