Human immunodeficiency virus
The human immunodeficiency virus (HIV) infects cells of the immune system, thereby increasing vulnerability to opportunistic infections. As the infection progresses, people living with HIV develop acquired immunodeficiency syndrome (AIDS), the most advanced stage of HIV. Antiretroviral treatment slows this progression, but there is currently no cure for HIV. HIV can be transmitted through (1) unprotected sex, (2) contaminated blood, (3) needle sharing and (4) during pregnancy, childbirth and breastfeeding.
In 2010, 34 million people were living with HIV, including 2.7 million new infections. 1.8 million people suffered from HIV-related deaths. (Source: (1) WHO Universal Access Progress Report 2011)
In recent years, new infections and deaths from HIV have declined. However, more than half of people living with HIV who are eligible for treatment lack access to it. With funding increasingly under pressure, this jeopardizes the continued scale-up of life saving interventions. (Source: (1) WHO Universal Access Progress Report 2011).
Tuberculosis (TB) is an infectious bacterial disease typically transmitted through the air. TB often remains latent for many years with no symptoms. Progression to active TB usually occurs when the immune system is compromised. TB is curable with antibiotics.
In 2010, 8.8 million people were living with active TB, with 4.6 million people accessing treatment. 1.5 million people suffered from TB-related deaths. (Source: (2) WHO Global Tuberculosis Control 2011 Report)
Despite progress in the fight against TB, the World Health Organization (WHO) warns that new infections will continue if global investment in prevention activities is not sustained. The funding gap is estimated at US$ 1 billion. (2)
Co-infection of TB and HIV
TB is one of the most common opportunistic infections for people living with HIV, who are over twenty times more likely to develop active TB than those without HIV. (2) Moreover, each disease accelerates the progress of the other.
In 2010, 1.1 million people living with HIV developed active TB. 350,000 people suffered HIV-related deaths due to TB, representing 19% of HIV-related deaths. (2)
In recognition of the relationship between HIV and TB, WHO has developed a set of guidelines for countries in resource-limited settings that aim to limit co-infection and support recovery from TB. (Source: (3) WHO)