A behavioural cohort component projection model for projecting the demographic impact of HIV/AIDS and the likely impact of interventions, including ART

Rob Dorrington, University of Cape Town
Leigh Johnson, University of Cape Town

The ASSA2002 AIDS and Demographic model is a public domain spreadsheet behavioural cohort component projection model for projecting the demographic impact of HIV/AIDS on a county’s population allowing for the impact of five different interventions, including ART. This paper describes the model and its rationale, and the basis for setting the parameters in the model, some set to best estimates from the literature, others by a process of calibrating the model to empirical observations of the impact of the epidemic. The paper compares, for South Africa, the fit of the model to the following data: prevalence from a national pps survey of antenatal clinics over a number of years; a national household prevalence survey; and deaths from vital registration (adjusted for under-recording). The performance of the model is contrasted with projections from UNAIDS/WHO, US Census Bureau and UN Population Division, and certain conclusions drawn.