Current estimates of HIV prevalence and incidence: sources and data.

The acquired immune deficiency syndrome (AIDS) is in reality only the most severe manifestation of an aggregate of overlying and interacting smaller epidemics. Distribution of these epidemics in the population remains extremely variegated and localized, making assessment of HIV prevalence and incidence extremely difficult. Data from a wide range of population surveys does give an indication of the number of persons infected. A working estimate, based on mathematical modeling and expert consensus, is that 1-1.5 million persons in the United States are currently infected.