The Epidemiology of HIV and AIDS

The impact of HIV-1 on Africa has been devastating, and the number of people already infected with HIV means that its impact will inevitably worsen in coming decades. However, the lessons learned from the successful responses to this problem, which have resulted in sustained reductions in HIV prevalence in some areas, demonstrate that it is possible to reduce the spread of the epidemic and to mitigate its impact. To do so requires comprehensive responses that take account not only of the heterogeneity of the epidemic but the complex social, population, and biologic dynamics that determine the course of the epidemic.