1.7 Global burden of tuberculosis

1.7.1 Latent tuberculosis infection

The global prevalence of LTBI is unknown due to difficulties in diagnosis. However, it is estimated that one-quarter of the world's population has LTBI [1] Citation 1. Houben RM, Dodd PJ. The Global Burden of Latent Tuberculosis Infection: A Re-estimation Using Mathematical Modelling. PLoS Med. 2016;13(10):e1002152. Published 2016 Oct 25.
https://doi.org/10.1371/journal.pmed.1002152 .

1.7.2 Active tuberculosis

Globally, active TB remains a leading cause of death from infectious disease.

WHO estimated that in 2022 there were 10.6 million incident cases of TB and 1.3 million deaths due to TB, including 1.1 million among people with no HIV infection and 167,000 among people with HIV infection [2] Citation 2. World Health Organization. Global Tuberculosis Report 2023. Geneva: World Health Organization; 2023.
9789240083851-eng.pdf (who.int) .
Patients under 15 years account for 12% of all estimated TB cases [2] Citation 2. World Health Organization. Global Tuberculosis Report 2023. Geneva: World Health Organization; 2023.
9789240083851-eng.pdf (who.int) . However, TB cases in children are frequently undiagnosed and unreported.

While the absolute number of global TB cases is stable, there are large individual country and regional differences in incidence and prevalence.

Most TB cases are in Southeast Asia (46%), Africa (23%) and the Western Pacific (18%), with lower percentages in the Eastern Mediterranean, the Americas and Europe [2] Citation 2. World Health Organization. Global Tuberculosis Report 2023. Geneva: World Health Organization; 2023.
9789240083851-eng.pdf (who.int) .

1.7.3 Drug-resistant tuberculosis 

Drug-resistant TB (DR-TB) is a growing worldwide problem, and no region is spared.

WHO estimates that annually worldwide there are:

• More than one million rifampicin-susceptible and isoniazid-resistant TB (Hr-TB) cases (11% of all incident TB cases) [3] Citation 3. World Health Organization. Global Tuberculosis Report 2020. Geneva: World Health Organization; 2020.
  https://apps.who.int/iris/rest/bitstreams/1312164/retrieve .
• 3.3% of new cases and 17% of previously treated cases, with multidrug-resistant TB (MDR-TB) a Citation a. Multidrug-resistant TB: resistance to at least rifampicin and isoniazid. and rifampicin-resistant TB (RR-TB) b Citation b. Rifampicin-resistant TB: resistance to rifampicin, with or without resistance to other TB drugs. representing 410,000 cases and 160,000 deaths [2] Citation 2. World Health Organization. Global Tuberculosis Report 2023. Geneva: World Health Organization; 2023.
  9789240083851-eng.pdf (who.int) .

In Eastern Europe and Central Asia, TB incidence is lower than in Southeast Asia and Africa, but up to 30% of new and 65% of retreatment cases exhibit rifampicin-resistance [3] Citation 3. World Health Organization. Global Tuberculosis Report 2020. Geneva: World Health Organization; 2020.
https://apps.who.int/iris/rest/bitstreams/1312164/retrieve .

In China and India, there is a low proportion of rifampicin-resistant cases among all TB cases. However, because of their large populations, these two countries represent 41% of global MDR/RR-TB cases [3] Citation 3. World Health Organization. Global Tuberculosis Report 2020. Geneva: World Health Organization; 2020.
https://apps.who.int/iris/rest/bitstreams/1312164/retrieve .

Resources for detecting drug resistance are limited in many parts of Africa. However, available data suggest that the MDR-TB burden is significant, especially in the south.

The prevalence of extensively drug-resistant TB (XDR-TB) c Citation c. Extensively drug-resistant TB: MDR/RR-TB with additional resistance to any fluoroquinolone, and at least either bedaquiline or linezolid. , according to the new WHO definition [4] Citation 4. World Health Organization. Meeting report of the WHO expert consultation on the definition of extensively drug-resistant tuberculosis, 27-29 October 2020. Geneva: World Health Organization; 2021. CC BY-NC-SA 3.0 IGO.
https://iris.who.int/bitstream/handle/10665/338776/9789240018662-eng.pdf?sequence=1 , is currently unknown.

The estimated proportion of pre-XDR TB d Citation d. Pre-extensively drug-resistant TB: MDR/RR-TB with additional resistance to any fluoroquinolone. among MDR/RR-TB cases is 18% [2] Citation 2. World Health Organization. Global Tuberculosis Report 2023. Geneva: World Health Organization; 2023.
9789240083851-eng.pdf (who.int) .