8, range 12–45) and 25.2 years (SD 7.9, range 16–56), respectively; 185 of

463 women reported having had at least one previous pregnancy. Four of the 47 master pools testing positive with the qualitative HIV-1 RNA assay required 40 individual samples to be tested. A total of 87 tests were performed (47 master pools and 40 individual tests) at a cost of 483 South African rand (R483; selleck compound approximately US$61, £40) per test, making, in total, R42 021.00 (US$5253, £3502). The cost per individual HIV-negative sample was R90.00 (US$11, £8), while the cost of identifying a single case of AHI was R10 505.00 (US$1313, £876). In this study using the HIV-1 RNA pooled NAAT strategy, we identified 0.9% of pregnant women with AHI in the absence of HIV antibodies. During the early years of the HIV epidemic, among mother–infant pairs attending immunization clinics in rural KwaZulu-Natal, 2% of women were diagnosed with acute incident HIV infections [4]. Our study reaffirms that a high proportion of pregnant women with HIV infection are unlikely to be diagnosed, and the potential for vertical and heterosexual transmission predicted by the magnitude of the viral load

[2,3] during the acute stage of infection has important public health implications. The HIV incidence of 11.2% per year in this study is similar to the 10.7 per 100 person-years obtained following retesting of HIV-negative pregnant women around the time of delivery from urban and rural facilities in South Africa [11]. While measuring HIV incidence by the traditional follow-up of cohorts of HIV-uninfected selleck products individuals remains the gold standard, these studies are usually time-consuming, expensive and potentially biased by poor retention

rates. From such studies, HIV incidence rates among 18–25-year-old nonpregnant women in Hlabisa and Durban, South Africa, were 8.9 and 8.5 per 100 person-years, respectively [12], indicative of the unrelentingly high HIV incidence rates in young women in this region. To estimate HIV incidence from cross-sectional studies, antibody-based sensitive/less sensitive testing [13] and the HIV-1 subtypes B, E, and D immunoglobulin G capture enzyme immunoassay (BED-CEIA) [14] have been used. tuclazepam Using BED-CEIA, data from population-based household surveys in South Africa have shown the HIV incidence to be 5.6% among women aged 20–29 years, compared with 0.9% in men of the same age group. Among women with a current pregnancy, the HIV incidence was 5.2% (95% CI 0.0–12.9) [14]. A key disadvantage of the BED-CEIA is that it is known to misclassify early or AHI with established long-term infections and individuals on ART [5]. In the absence of HIV antibodies, the measurement of HIV-1 RNA and p24 antigen are both highly sensitive and specific, with HIV-1 RNA having an added advantage of being detected much earlier than p24 antigen [5,6].