The HIV-1 epidemic in South Africa: The leading edge and the measurement of incidence

Abstract

The first reported cases of human immunodeficiency virus type 1 (HIV-1) infection in South Africa were seen in 1982. South Africa has currently the highest absolute number of cases of HIV in the world. Various HIV prevalence surveys, including sentinel surveys and household surveys, have been performed over the years, and the epidemic is characterised as generalised and mature. Multiple interventions, including a large-scale antiretroviral programme, have been introduced in South Africa to reduce the transmission of HIV. It is thus no longer sufficient to estimate prevalence to understand the dynamics of the epidemic. Knowledge of the HIV incidence, the leading edge of the epidemic, would be ideal. In particular, laboratory-based incidence estimates are seen as the answer. Several laboratory methods have been described, but these have turned out to be relatively imperfect, and various refinements have been described to obtain relatively useful data. Nevertheless, in the case of South Africa, high levels of incidence have been described based on observational and laboratory-based data. The continued incidence studies are critical to inform about the leading edge of the epidemic.