In plain words
Tuberculosis (TB) is an infectious disease caused by bacteria that most often affect the lungs. It spreads through the air when a person with TB disease coughs, sneezes or spits.
TB is preventable and curable.
Key facts
- WHO reports 1.23 million deaths from TB in 2024 and an estimated 10.7 million people who fell ill.
- TB is the leading cause of death from a single infectious agent worldwide.
- About a quarter of the world population is estimated to have been infected, but most infected people do not feel sick and are not contagious.
- About 5 to 10% of infected people go on to develop TB disease.
- Only about 2 in 5 people with drug-resistant TB accessed treatment in 2024.
Infection and disease
TB infection and TB disease are different. In infection the person feels well and is not contagious. In disease the bacteria multiply and cause symptoms, usually in the lungs but also in the kidneys, brain or spine. Symptoms can be mild for months, so TB can spread unnoticed.
Who is at higher risk
Babies and children who become infected, and people with diabetes, a weakened immune system such as HIV, undernutrition, tobacco use or harmful alcohol use.
Prevention and treatment
The BCG vaccine is given to babies or small children in some countries and prevents deaths and serious forms of TB in children. TB disease is usually treated with antibiotics and can be fatal without treatment.
Sources
- WHO fact sheet, Tuberculosis, published 24 March 2026, read 9 October 2026.
Last reviewed: 9 October 2026. Reviewer: none yet. This page is general education and is not medical advice. Figures are WHO's and may have been updated since.