What is the link between HIV and TB?
TB is a leading cause of death in HIV infected patients. TB and HIV have a mutually negative relationship. As HIV progresses CD4+ cell counts drop, the co-infected patient suffers from immunodeficiency, which leads to increased susceptibility to active TB (up to 10x more likely than someone that is HIV negative).2 HIV is driving the TB epidemic in many countries such as Sub-Saharan Africa (up to 50% of TB patients in African countries are also HIV positive), Asia and South America.3 Extrapulmonary TB is more common in those co-infected with HIV as the ‘immune system becomes less able to prevent growth and local spread’.
HIV infection leads to progressive weakening of the immune system. The body therefore cannot fight infections effectively and there is an increased susceptibility to infections, including TB. As HIV infection progresses, the immune system is less able to prevent the growth and spread of TB. Without HIV, only about 10% of people infected with TB get sick with TB. In people with HIV, about 50% develop active TB disease. Currently, in South Africa half of TB patients are co-infected with HIV. The high levels of active TB in persons living with HIV pose an increased risk of TB transmission to the general community. The impact of both infections, HIV & TB, make the body’s immune system weak. TB is also more difficult to diagnose when a person has advanced HIV infection.
