HIV stands for Human Immunodeficiency Virus and it is the virus that causes AIDS; which stands for Acquired Immune Deficiency Syndrome. The main difference being that a person can have HIV without having AIDS, but HIV is what causes AIDS.

The progression of HIV to AIDS is a continuum where AIDS is the end result, but different organizations have different definitions about when HIV becomes AIDS. According to the World Health Organization, the progression happens in four stages; the virus is in the body, but the person is asymptomatic, then sores in the mouth and other mucous membranes appear and upper respiratory tract infections start happening more frequently, next the person suffers from chronic diarrhea, tuberculosis and other serious lung infections, and finally brain complications, widespread candidiasis infections and Kaposi’s sarcoma, the hallmark skin lesions seen in AIDS patients. It is in this fourth stage that a person is classified as having AIDS.

According to the Center for Disease Control and Prevention, HIV become AIDS when there are fewer than 200 CD4+T Cells per microliter of blood. Nine out of ten patients will develop AIDS within 10 to 15 years after contracting HIV. Treatment with antiretroviral drugs after a diagnosis of AIDS infection can prolong a patient’s life by up to 5 years or more. Without them, a patient can die in a year.