Estimating and Projecting the Size and Impact of HIV/AIDS Epidemic: The UNAIDS Reference Group Approach

John Stover, Futures Group International
Karen A. Stanecki, U.S. Census Bureau

Every two years UNAIDS prepares estimates of the HIV/AIDS epidemic for every country in the world. In preparation for the 2001 round of estimates, the UNAIDS Reference Group on Models, Estimates and Projections developed a new approach and updated many projection assumptions. The new approach includes (1) a new model (Epidemic Projection Package) for estimating and projecting HIV prevalence from HIV surveillance data; (2) updated assumptions about rates of progression from infection to death for adults and children, the fertility impact of HIV, and the distribution of HIV infection by age and sex; (3) an updated version of the Spectrum software to integrate HIV and population projections with the latest demographic estimates from the UN Population Division and (4) a new methodology for estimating maternal, paternal and double AIDS orphans. This paper describes the methodology, assumptions and results from this new approach.