Perspective
Key facts
A total of 1.5 million people died from TB in 2018 (including 251 000 people with HIV). Worldwide, TB is one of the top 10 causes of death and the leading cause from a single infectious agent (above HIV/AIDS).
In 2018, an estimated 10 million people fell ill with tuberculosis(TB) worldwide. 5.7 million men, 3.2 million women and 1.1 million children. There were cases in all countries and age groups. But TB is curable and preventable.
In 2018, 1.1 million children fell ill with TB globally, and there were 205 000 child deaths due to TB (including among children with HIV). Child and adolescent TB is often overlooked by health providers and can be difficult to diagnose and treat.
In 2018, the 30 high TB burden countries accounted for 87% of new TB cases. Eight countries account for two thirds of the total, with India leading the count, followed by, China, Indonesia, the Philippines, Pakistan, Nigeria, Bangladesh and South Africa.
Multidrug-resistant TB (MDR-TB) remains a public health crisis and a health security threat. WHO estimates that there were 484 000 new cases with resistance to rifampicin – the most effective first-line drug, of which 78% had MDR-TB.
Globally, TB incidence is falling at about 2% per year. This needs to accelerate to a 4–5% annual decline to reach the 2020 milestones of the End TB Strategy.
An estimated 58 million lives were saved through TB diagnosis and treatment between 2000 and 2018.
Ending the TB epidemic by 2030 is among the health targets of the Sustainable Development Goals.
Tuberculosis (TB) is caused by bacteria (Mycobacterium tuberculosis) that most often affect the lungs. Tuberculosis is curable and preventable.
TB is spread from person to person through the air. When people with lung TB cough, sneeze or spit, they propel the TB germs into the air. A person needs to inhale only a few of these germs to become infected.
About one-quarter of the world's population has latent TB, which means people have been infected by TB bacteria but are not (yet) ill with the disease and cannot transmit the disease.
People infected with TB bacteria have a 5–15% lifetime risk of falling ill with TB. Persons with compromised immune systems, such as people living with HIV, malnutrition or diabetes, or people who use tobacco, have a higher risk of falling ill.
When a person develops active TB disease, the symptoms (such as cough, fever, night sweats, or weight loss) may be mild for many months. This can lead to delays in seeking care, and results in transmission of the bacteria to others. People with active TB can infect 5–15 other people through close contact over the course of a year. Without proper treatment, 45% of HIV-negative people with TB on average and nearly all HIV-positive people with TB will die.
Who is most at risk?
Tuberculosis mostly affects adults in their most productive years. However, all age groups are at risk. Over 95% of cases and deaths are in developing countries.
People who are infected with HIV are 19 times more likely to develop active TB (see TB and HIV section below). The risk of active TB is also greater in persons suffering from other conditions that impair the immune system. People with undernutrition are 3 times more at risk. There were globally 2.3 million new TB cases in 2018 that were attributable to undernutrition.