South Africa: Questions about new prevalence survey

Tshabalala-Msimang's statement was based on a national survey of HIV prevalence among pregnant women, which researchers are describing as deeply flawed.

The report, posted on the health department's website on 29 August, states that prevalence among pregnant women fell from 29.1 percent in 2006 to 28 percent in 2007.

Prof Rob Dorrington, a demographer at the University of Cape Town, and his colleague, Prof David Bourne, point out in a letter published in the South African Medical Journal (SAMJ) this week that the 2007 survey employed a methodology not only radically different from that used in 2006, but also "manifestly wrong".

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