The U.S. Department of Health and Human Services' AIDS.gov website reports that people infected with the human immunodeficiency virus who progress to acquired immune deficiency syndrome have a life expectancy of around 3 years. People with AIDS and a severe opportunistic illness tend to survive only for approximately 1 year.
By the point at which an HIV-positive person reaches the AIDS stage, her immune system is severely compromised, rendering her highly vulnerable to infections and related cancers known as opportunistic infections. People who are undergoing antiretroviral therapy, or ART, on a consistent basis are likely never to progress to the AIDS stage of HIV infection, according to AIDS.gov. ART allows many HIV-positive people to live lives lasting almost as long as the normal life span. Doctors diagnose AIDS when a person has a CD4 cell count of fewer than 200 cells per cubic millimeter of blood or when she develops an opportunistic illness regardless of her CD4 cell count.
Progression to the AIDS stage occurs after the clinical latency stage of the HIV infection, which can last for fewer than 10 years without treatment or for several decades when the infected person undergoes ART, according to AIDS.gov. The acute infection stage, which has symptoms that resemble a severe case of the flu, comes first and lasts for a shorter period of time. This state begins a few weeks after the virus enters the body.