Correlates of Mother‐to‐Child Human Immunodeficiency Virus Type 1 (HIV‐1) Transmission: Association with Maternal Plasma HIV‐1 RNA Load, Genital HIV‐1 DNA Shedding, and Breast Infections

TLDR

Reducing infant exposure to HIV‑1 in maternal genital secretions or breast milk could strengthen existing perinatal HIV‑1 prevention strategies. The study aimed to assess how maternal plasma, genital, and breast milk HIV‑1, along with breast infections, influence perinatal HIV‑1 transmission. Researchers conducted a nested case‑control analysis within a randomized trial comparing breast‑feeding and formula feeding among HIV‑1‑positive mothers in Nairobi, Kenya. Maternal plasma HIV‑1 RNA >43,000 copies/mL quadrupled transmission risk, and cervical/vaginal HIV‑1 DNA and genital ulcers independently increased risk, while breast‑feeding, mastitis, and breast abscesses further elevated transmission, especially for infections occurring after two months postpartum.

Abstract

To determine the effects of plasma, genital, and breast milk human immunodeficiency virus type 1 (HIV-1) and breast infections on perinatal HIV-1 transmission, a nested case-control study was conducted within a randomized clinical trial of breast-feeding and formula feeding among HIV-1-seropositive mothers in Nairobi, Kenya. In analyses comparing 92 infected infants with 187 infants who were uninfected at 2 years, maternal viral RNA levels >43,000 copies/mL (cohort median) were associated with a 4-fold increase in risk of transmission (95% confidence interval [CI], 2.2-7.2). Maternal cervical HIV-1 DNA (odds ratio [OR], 2.4; 95% CI, 1.3-4.4), vaginal HIV-1 DNA (OR, 2.3; 95% CI, 1.1-4.7), and cervical or vaginal ulcers (OR, 2.7; 95% CI, 1.2-5.8) were significantly associated with infant infection, independent of plasma virus load. Breast-feeding (OR, 1.7; 95% CI, 1.0-2.9) and mastitis (relative risk [RR], 3.9; 95% CI, 1.2-12.7) were associated with increased transmission overall, and mastitis (RR, 21.8; 95% CI, 2.3-211.0) and breast abscess (RR, 51.6; 95% CI, 4.7-571.0) were associated with late transmission (occurring >2 months postpartum). Use of methods that decrease infant exposure to HIV-1 in maternal genital secretions or breast milk may enhance currently recommended perinatal HIV-1 interventions.