Abstract
BACKGROUND: In Ethiopia, where vertical transmission (VT) of HIV remains high, this study investigates the impact of maternal virological failure (VF) on VT outcomes. METHODS: A retrospective cohort of 541 HIV-positive pregnant women from three high-prevalence hospitals was analyzed using bivariable and multivariable logistic regression. RESULTS: Multivariable logistic regression revealed that maternal VF was strongly associated with VT of HIV. Mothers with VF were nearly ten times more likely to transmit HIV to their infants compared to those with viral suppression (AOR = 9.96; 95% CI 3.19-31.11; p < 0.001). Additional independent predictors of VT included ART initiation during pregnancy (AOR = 3.54; 95% CI 1.48-8.48; p = 0.005), baseline CD4 count ≤ 350 cells/mm3 (AOR = 5.66; 95% CI 2.67-12.00; p < 0.001), poor ART adherence (AOR = 8.09; 95% CI 3.09-21.24; p < 0.001), and absence of infant nevirapine prophylaxis (AOR = 6.54; 95% CI 2.42-17.69; p < 0.001). CONCLUSION: Maternal VF was strongly associated with increased risk of VT. These findings highlight the importance of early initiation of ART, consistent viral suppression, adherence support, and routine viral load monitoring as key strategies to reduce VT, particularly in high-burden settings. Strengthening these interventions may help target the small subset of mothers at highest risk and improve overall prevention outcomes.