Despite global improvements in antiretroviral therapy (ART) access for children and adolescents living with HIV (CALHIV), a significant proportion continue to experience unsuppressed viral load (USVL). Limited studies focus on the factors contributing to USVL among CALHIV in the Democratic Republic of the Congo (DRC), especially in the context of evolving treatment landscapes. Understanding these determinants is crucial for enhancing ART outcomes.

This study aimed to determine the prevalence of USVL and identify factors associated with USVL among CALHIV receiving ART in Lubumbashi, DRC.

A multicentre retrospective cross-sectional study was conducted. Data were gathered using an observational checklist based on assessing patient file data and entered into Microsoft Excel. Analysis was performed using STATA V.16. Variables with a p value of 0.20 from the bivariable analysis were included in a multivariable logistic regression model, and significant variables (p

The study was conducted at 21 HIV care clinics in Lubumbashi from June to September 2024. It included 847 CALHIV aged 0–19 years who had been on ART for at least 6 months and had at least one available VL result.

The rate of USVL among CALHIV, defined as achieving a VL below 1000 copies/mL, in those who had been on ART for at least 6 months.

The prevalence of USVL among CALHIV was 24.68% (209/847; 95% CI: 21.89% to 27.69%). Multivariable logistic regression analysis revealed that CALHIV with married caregivers were more likely to have USVL (adjsuted OR, aOR=2.4; 95% CI: 1.2 to 5.0). Other factors associated with USVL included horizontal HIV transmission (aOR=2.3; 95% CI: 1.0 to 5.2), advanced WHO clinical stages (aOR=3.5; 95% CI: 1.0 to 13.7), poor/fair ART adherence (aOR=107.8; 95% CI: 50.3 to 231.1) and ART-induced side effects (aOR=3.8; 95% CI: 1.9 to 7.9).

The high rate of USVL among CALHIV in Lubumbashi highlights the need to strengthen ART adherence support, manage treatment side effects and improve early diagnosis and follow-up, particularly for those infected through horizontal transmission or presenting with advanced clinical stages. Special attention should also be given to caregiver-related factors, including marital status, which may influence treatment outcomes.