Three-year virological outcomes among adolescent girls and young women (AGYW) living with HIV enrolled in vertical transmission prevention services during pregnancy and postpartum in Tanzania: A Prospective Cohort Study.

Abstract Objective This large cohort study examines long-term trends and predictors of viremia among pregnant and postpartum adolescent girls and young women (AGYW) living with HIV in Tanzania. Methods This prospective cohort study included 7,703 pregnant/postpartum AGYW with at least one viral load (VL) enrolled in routine PMTCT care between 2018 and 2020 across three regions in Tanzania and followed for a minimum of 36 months. Poisson generalized Linear Models (log link) estimated adjusted incident rate ratios (aIRRs) and 95% confidence intervals (CIs) for detectable viremia (VL≥50 copies/mL) by baseline exposures. Results Over three years, detectable viremia was higher among the youngest aged 15-17 (20·4%), compared to 18–19 years (16·7%) and 20–24 years (12·5%). Viremia declined during pregnancy but plateaued postpartum, with over 10% remaining viremic. Perinatally infected AGYW (HIV diagnosis before ≤12 years) had higher viremia (28·8%) than those on ART (11·0%) and new on ART (15·2%) who were diagnosed after childhood. Over 25% of perinatally infected AGYW remained viremic throughout the PMTCT cycle. Second-line ART and urban residence were associated with higher risk of viremia. Conclusion Persistently high viremia was observed over time among Tanzanian pregnant/postpartum AGYW with HIV, particularly among adolescents and those with perinatally acquired infection. Tailored PMTCT interventions, including resistance-informed treatment and youth-friendly adherence support, are needed to improve maternal outcomes and accelerate elimination of vertical transmission.