Evaluation of postpartum HIV superinfection and mother-to-child transmission

Abstract

OBJECTIVE: This study examined HIV superinfection in HIV-infected women postpartum, and its association with mother-to-child transmission (MTCT). DESIGN: Plasma samples were obtained from HIV-infected women who transmitted HIV to their infants after 6 weeks of age (transmitters, n = 91) and HIV-infected women who did not transmit HIV to their infants (nontransmitters, n = 91). These women were originally enrolled in a randomized trial for prevention of MTCT of HIV in Malawi (Post-Exposure Prophylaxis of Infants trial in Malawi). METHODS: Two HIV genomic regions (p24 and gp41) were analyzed by next-generation sequencing for HIV superinfection. HIV superinfection was established if the follow-up sample contained a new, phylogenetically distinct viral population. HIV superinfection and transmission risk were examined by multiple logistic regression, adjusted for Post-Exposure Prophylaxis of Infants study arm, baseline viral load, baseline CD4 cell count, time to resumption of sex, and breastfeeding duration. RESULTS: Transmitters had lower baseline CD4 cell counts (P = 0.001) and higher viral loads (P