Re-estimated provincial HIV antenatal survey prevalence for 2007 and a reinterpretation of the national trend.

Using the information provided at the district level in the latest report for 2007, we have calculated the provincial prevalence applying the method used in the 2006 report. This involves simply summing the number of HIV-positive cases per district sample and dividing by the total sampled population for the province. The national prevalence is estimated as the weighted average of the provincial prevalence rates, using the number of women in the 15 49 years age band in total in each province as weights. When this method is applied to the 2007 district data it does not reproduce the published provincial estimates for 2007!