The average time from HIV infection to disease onset is about 9 years, with most patients in the 6-10 year time frame. Of course it is not absolute, some people may develop the disease in about 1-2 years, and the length of time it takes to develop the disease is related to the amount of HIV infection, and the individual’s autoimmune status. Most people infected with HIV are in the asymptomatic phase, also known as the incubation period, when the patient does not have any clinical symptoms, but has HIV in his or her body and is infectious. As the disease progresses, the HIV virus destroys the immune system in the body, resulting in various opportunistic infections. The most common opportunistic infection is Pneumocystis carinii pneumonia, and many patients die of respiratory failure.