Pre-Antiretroviral Therapy Vertical HIV-1 Transmission Risk in Uganda Varies by Sex of Child and Maternal Viral Subtype.
We analyzed perinatal transmission in a pre-antiretroviral therapy Ugandan cohort by maternal human immunodeficiency virus type 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 compared with subtype D (risk ratio [RR], 2.96 [95% confidence interval (CI), 1.46-6.01]; P = .008). When stratifying infants by both sex and maternal subtype, significantly more female (56.3% [9 of 16]) than male (9.1% [1 of 11]) infants born to mothers with subtype A were infected (RR, 6.19 [95% CI, .91-42.12]; P = .02). In contrast, among infants born to mothers with subtype D, transmission rates were comparable across sex (RR, 1.59 [95% CI, .57-4.41]; P = .39).