National Population-Based HIV Surveys--the Method of Choice for Measuring the HIV Epidemic (Samj Forum) (Human Immunodeficiency Virus) (Report‪)‬

National population-based surveys that include HIV testing are considered to be the 'gold standard' to measure HIV prevalence at a country level, since such surveys include men, non-pregnant women and children, and hence a much wider proportion of the population than do antenatal surveys. (1) Three national HIV household surveys have been conducted in South Africa, the first in 2002, then in 2005 and 2008. These collected data on HIV status, socio-demographic factors and behavioural determinants as well as exposure to prevention programmes which greatly enhanced the analysis and interpretation of the trends in HIV infection. (2) In his appraisal of the 2008 survey report in this issue of SAMJ, Dorrington (3) questions the reliability of the survey findings and expresses concerns about the validity of our conclusions. He compares the HIV prevalence data obtained in the surveys with the estimates produced by his model, the ASSA AIDS and Demographic Model. (4) Findings that were not close enough to those projected by the ASSA model are declared 'not in line with expectation' and therefore implausible. In this debate one should not forget that it is empirical data that greatly improved the outputs of projection models. A prime example of this process is the ASSA model: the ASSA estimates of HIV-infected people for the year 2005 dropped from 7.6 million to 5.2 million (!) after the creator of the model re-calibrated the projections with data available from the national HIV household surveys. (5,6)