Weighted relative proportion of maternal HIV seroconversions during pregnancy and early mother to child transmission of HIV (MTCT) by time of maternal HIV infection identified group, South Africa, 2011–2012.

<p>This figure shows the distribution of awareness of HIV infection for all HIV-infected mothers, and for all mothers who transmitted HIV-infection to their infants. Mothers are categorized as a) knowing they were infected prior to this pregnancy (solid black) b) newly identified as HIV-infected during this pregnancy (upward diagonal lines) c) identified as HIV-infected by testing of infant dried blood spot specimens after reported not knowing their HIV status in our survey (solid grey box) and d) identified as HIV-infected by testing of iDBS after reporting testing HIV-negative in our survey, and with no other evidence of HIV infection reported on the infants child health card (light grey downward diagonal lines). Percentages are adjusted for the sampling design including clustering, design effects and nonresponse, and weighted to the population distribution of live-births for South Africa (SA) in 2011. It shows that, although women who seroconverted after a negative HIV test represent only 6.7% of the population of HIV-infected pregnant women in SA in 2011, these mothers accounted for 26.0% of all maternal to child transmission of HIV.