AIDS: the HIV epidemic. A time of transition.

The surveillance of clinical cases of acquired immune deficiency syndrome (AIDS) in the United States began in June 1981 when the first case was reported. Since then, state and federal public health officials have continuously monitored progression of the epidemic by the number of persons reported with diagnosed clinical AIDS. The human immunodeficiency virus (HIV) that causes AIDS was identified in 1983 and an antibody test was licensed by the Food and Drug Administration in 1985. Recent studies have shown that the time from HIV infection to development of clinical AIDS is an average of seven or more years. Consequently, the reported cases of clinical AIDS reflect the severity of the epidemic an average of seven years ago or more, not now, and certainly not in the future. The AIDS epidemic is in reality an HIV epidemic. The number of persons with HIV infections is a better measure of the present status and future course of the disease. This paper discusses the development of HIV prevalence and incidence studies and illustrates the use of these data to predict the future number of persons with clinical AIDS and the economic impact of the epidemic.