Impact of maternal HIV seroconversion during pregnancy on early mother to child transmission of HIV (MTCT) measured at 4-8 weeks postpartum in South Africa 2011-2012: A national population-based evaluation
Centers for Disease Control and Prevention, Center for Global Health, Division of Global HIV/AIDS, Atlanta, GA, United States; Centers for Disease Control and Prevention, National Center for HIV, Hepatitis, STD, and Tuberculosis Prevention, Division of HIV/AIDS Prevention, Atlanta, GA, United States; Medical Research Council, Pretoria, South Africa; Department of Paediatrics and Child Health, Kalafong Hospital, University of Pretoria, Pretoria, South Africa; Medical Research Council, Cape Town, South Africa; School of Public Health, University of the Western Cape, Bellville, South Africa; US Centers for Disease Control and Prevention, Center for Global Health, Division of Global HIV/AIDS, Pretoria, South Africa; National Department of Health, Pretoria, South Africa; World Health Organization, Geneva, Switzerland; United Nations Children's Fund, New York, United States
Background: Mother-to-child transmission of HIV (MTCT) depends on the timing of HIV infection. We estimated HIV-seroconversion during pregnancy (HSP) after having a HIV-negative result antenatally, and its contribution to early MTCT in South Africa (SA). Methods and Findings: Between August 2011 and March 2012, we recruited a nationally representative sample of mother-infant pairs with infants aged 4-to-8 weeks from 578 health facilities. Data collection included mother interviews, child health-card reviews, and infant dried-blood-spots sample (iDBS). iDBS were tested for HIV antibodies and HIV-deoxyribonucleic-acid (HIV-DNA). HSP was defined as maternal self-report of an HIV-negative test during this pregnancy, no documented use of antiretroviral drugs and a matched HIV sero-positive iDBS. We used 20 imputations from a uniform distribution for time from reported antenatal HIV-negative result to delivery to estimate time of HSP. Early MTCT was defined based on detection of HIV-DNA in iDBS. Estimates were adjusted for clustering, nonresponse, and weighted by SA's 2011 live-births. Results: Of 9802 mother-infant pairs, 2738 iDBS were HIV sero-positive, including 212 HSP, resulting in a nationally weighted estimate of 3.3% HSP (95% Confidence Interval: 2.8%-3.8%). Median time of HIV-seroconversion was 32.8weeks gestation;28.3% (19.7%- 36.9%) estimated to be >36 weeks. Early MTCT was 10.7%for HSP (6.2%-16.8%) vs. 2.2% (1.7%-2.8%) for mothers with known HIV-positive status. Although they represent 2.2% of all mothers and 6.7% of HIV-infected mothers, HSP accounted for 26% of early MTCT. Multivariable analysis indicated the highest risk for HSP was among women who knew the baby's father was HIV-infected (adjusted-hazard ratio (aHR) 4.71; 1.49-14.99), or who had been screened for tuberculosis (aHR 1.82; 1.43-2.32). Conclusions: HSP risk is high and contributes significantly to early MTCT. Identification of HSP by repeat-testing at 32 weeks gestation, during labor, 6 weeks postpartum, in tuberculosis-exposed women, and in discordant couples might reduce MTCT. © 2015, Public Library of Science. All rights reserved.
DNA; Human immunodeficiency virus antibody; adult; Article; controlled study; disease transmission; female; gestational age; human; Human immunodeficiency virus infection; infant; infection rate; infection risk; live birth; major clinical study; mother to child transmission; pregnancy; puerperium; self report; seroconversion; South Africa; virus transmission
CDC, Medical Research Council; 1U2GPS001137-02, MRC, Medical Research Council; 1U2GPS001137-03, MRC, Medical Research Council