The human immunodeficiency virus (HIV) is a retrovirus that infects cells of the immune system, destroying or impairing their function. As the infection progresses, the immune system becomes weaker, and the person becomes more susceptible to infections. The most advanced stage of HIV infection is acquired immunodeficiency syndrome (AIDS). It can take 10-15 years for an HIV-infected person to develop AIDS; antiretroviral drugs can slow down the process even further.

HIV is transmitted through unprotected sexual intercourse (anal or vaginal), transfusion of contaminated blood, sharing of contaminated needles, and between a mother and her infant during pregnancy, childbirth and breastfeeding।

10 facts on HIV/AIDS

July 2010

WHO

HIV/AIDS remains one of the world's most significant public health challenges, particularly in low- and middle-income countries.

Thanks to recent advances in access to antiretroviral therapy (ART), HIV-positive people now live longer and healthier lives. At the end of 2009, 5.2 million people in low- and middle-income countries received ART. However, approximately 10 million people in need of ART still have no access to treatment.

WHO works with Member States to help them scale-up and deliver comprehensive services in order to mitigate the spread of the disease and lessen its effects.

This fact file provides current data on the disease, and ways to prevent and treat it.

Read 10 facts on HIV/AIDS