Development and future directions for the Joint United Nations Programme on HIV/AIDS estimates

Abstract

Every year, the Joint United Nations Programme on HIV/AIDS (UNAIDS) produces estimates that chart the magnitude of the worldwide HIV epidemic, its impact and the progress taken to curb its spread and reduce its impact. The UNAIDS Reference Group on Estimates, Modelling and Projections [1] exists to review and develop the methods supported by UNAIDS to generate national estimates of HIV and related indicators. UNAIDS and its Reference Group routinely produce special editions of scientific journals to document the methods used to produce the UNAIDS estimates and to provide updates on the directions the methods are expected to take in the future [2–6]. The work of the Reference Group is two-fold – to continually calibrate, update and validate the methods, while simultaneously extending the methods to take advantage of new data sources, and to adapt approaches so as to maximise their usefulness to country programme planning and in evaluation. The articles in this supplement fall into both of these categories. Two articles document recent improvements to the estimation and projection models that are used, and another compares the UNAIDS estimates with other sets of published estimates and data. Several other articles show how the methods have expanded to accommodate the need to better understand data requirements for young children and older people; how estimates of key indicators are produced at finer spatial scales; and finally, how methods can and will synthesise newly available data into estimates. We address each of these topics in turn below. Together, these updates, modifications and new methods aim to provide more accurate knowledge and better understanding of HIV epidemics which should inform and assist programme planners and decision makers, as well as scientists, researchers and the wider public.