Accurately simulating the growth in the size of the HIV infected population in any AIDS epidemic country: Computing the U.S.A. HIV infection curve

A reliable approach to the simulation of the time-dependent growth of the size of a country's HIV population is described in detail and applied to the USA epidemic. The simulation depends on a knowledge of AIDS incidence data and the HIV incubation period distribution but is independent of any model regarding how the disease was spread. Using the Centers for Disease Control's December 31, 1991 update of the reported AIDS incidence data, a cumulative total of 645,445 Americans was calculated to be HIV infected as of January 1, 1991.The HIV infection curves for the USA risk groups were separately computed, and they indicate that the current rates of the spread of the infection in all of the risk groups are small fractions of what they were in the early phase of the epidemic. In fact, the calculated increase in the cumulative number of USA HIV infecteds from January 1, 1990 to January 1, 1991 was only 1.44%. These results suggest that the annual number of AIDS cases to be obtained in the next few years will not be substantially different from what it was in 1991. Since the calculated HIV infection curves for the transfusion and hemophiliac risk groups are currently growing at a particularly low rate, the modelling results confirm the great safety of the nation's blood and blood product supplies.