Does the 2008 HSRC survey indicate a turning tide of HIV prevalence in children, teenagers and the youth?

631 Recently the Human Sciences Research Council (HSRC) released its report 1 on the results of its third and most recent household prevalence survey. The main conclusion of the analysis is that 'some solid progress has been made in the fight against the disease in the past few years, especially among teenagers and children'. In particular the authors conclude: • that HIV prevalence at national level has decreased among children aged 2-14 years, from 5. • that HIV prevalence among adults aged 15-49 years has the declined between 2002 and 2008 in the Western Cape, Gauteng, Northern Cape and the Free State, 'with the largest decline of 7.9 [sic] percentage points in the Western Cape'. 2 How reliable are the results from the survey, and how reasonable are these conclusions? Despite the fact that the overall response rate (not given in the report, but easily calculated as 53% for those aged 2+) is slightly lower than that reported for the previous survey 3 (55%), the results of the survey appear to be as consistent with expectations as those of the previous survey. 4 As shown in Fig. 1, overall, the prevalence (among those aged 2+) from the survey (10.9%) is 1% below that expected on the basis of projections of the ASSA2003 model (11.9%), 5 although the prevalence for males (7.9%) is significantly lower than expected (10.8%). There may be grounds for believing that the ASSA2003 model exaggerates the prevalence in men a little. However, as with the previous HSRC survey, if one calculates the prevalence directly using the age-specific prevalence rates given in the report (and estimates of the midyear population 6) one gets estimates more in line with expectations – about 1% higher for males and 0.6% lower for females. This may suggest a problem with the weighting used in the survey to adjust for non-response. In the case of males in particular the lower prevalence could also be due in part to the fact that the survey may not be capturing some of the high-risk individuals. This could have happened either because they were expressly excluded (military, prisons, etc.) or because they are less likely than others to participate in such surveys (less likely to have a fixed home address or to be at home, etc.). In this regard it is a concern that the survey tested only about 46% of the number of men (aged 15+) …