Pre-ART Vertical HIV-1 Transmission Risk in Uganda Varies by Sex of Child and Maternal Viral Subtype

Abstract We analyzed perinatal transmission in a pre-ART Ugandan cohort by maternal HIV-1 subtype and infant sex in 131 mother-child pairs. Among all children, if the mother was infected with subtype A there was a nearly 3-fold increased risk of perinatal transmission as compared to subtype D (RR=2.96, CI=1.46-6.01, p=0.008). When stratifying infants by both sex and maternal subtype, significantly more female (56.3% [9/16]) than male (9.1% [1/11]) infants born to mothers with subtype A were infected (RR = 6.19, CI=0.91-42.12, p=0.02). In contrast, among infants born to mothers with subtype D, transmission rates were comparable across sex (RR=1.59, CI=0.57-4.41, p=0.39).