Tracking viral control in adolescents on antiretroviral therapy in Lusaka, Zambia: A retrospective cohort analysis.

Background: In 2023, an estimated 39.9 million people globally were living with HIV, of which 1.55 million were adolescents aged 10-19 years. The 2021 Zambia HIV Impact Assessment revealed lower viral suppression rates in adolescents (15-24 years old) compared to adults on antiretroviral therapy (ART). Lusaka District, Zambia, has the highest number of adolescents on ART, with a 15.1% HIV prevalence in 2018.

Objectives: To determine the prevalence and factors associated with viral suppression among adolescents living with HIV (10-19 years) on ART in Lusaka District, Zambia.

Method: A retrospective cohort analysis was done of 3409 adolescents on ART at public health facilities in Lusaka from January 2023 to December 2023, and who had viral loads recorded. Socio-demographic, clinical, treatment and behavioural data were extracted from electronic health records and analysed using SPSS version 29.

Results: The adolescent cohort in Lusaka achieved 91.8% viral suppression rate (< 1000 copies/mL), with 79% fully suppressed (< 50 copies/mL). In multivariate analysis, older adolescents (15-19 years) had lower odds of suppression compared to younger adolescents (10-14 years) (adjusted odds ratio [AOR] = 1.79; confidence interval [CI] : 1.32-2.43). Higher odds of viral suppression were linked to first-line dolutegravir regimen (AOR = 5.12; CI: 3.23-8.11) and optimal adherence (AOR = 1.89; CI: 1.03-3.47), while regimen switches reduced the odds of viral suppression (AOR = 0.60; CI: 0.45-0.80).

Conclusion: Zambia reached the previous UNAIDS 90-90-90 targets with a viral suppression rate of 91.8%. However, to reach the revised 95% target by 2030, tailored interventions should be implemented to improve adherence and retention in care, particularly for older adolescents.