Factors associated with viral load suppression among children and adolescents on dolutegravir-based antiretroviral regimen in Tanzania: a longitudinal analysis.

Introduction: Antiretroviral therapy (ART) reduces morbidity and mortality due to human immunodeficiency virus (HIV) infection. In 2019, Tanzania adopted Dolutegravir (DTG) as a first-, second-line, and third-line treatment for children and adolescents living with HIV (CALHIV). Viral load suppression (VLS) is desirable in the prevention of HIV transmission thus achieving the third '95' target. DTG treatment has highly potent antiviral activity, a high genetic barrier to resistance, and a high safety profile. We aimed to determine VLS and associated factors among CALHIV on DTG-based ART in Tanzania.

Methods: We conducted a retrospective cohort analysis among CALHIV who were on a DTG-based regimen in Tanzania between 2019 and 2021. We extracted demographic and clinical characteristics from the care and treatment clinic database. A multilevel mixed effects Poisson regression model was used to determine factors associated with VLS at < 1000 copies/ml among CALHIV on a DTG-based regimen.

Results: A total of 63,453 CALHIV on a DTG-based regimen were analysed. The proportion of viral suppression was 91.64%. Overall, 66.19% of previously unsuppressed individuals became suppressed, and 88.45% of previously suppressed remained suppressed. Factors leading to higher chances of viral suppression were aged 15-19 years (aRR: 1.02; 95%CI: 1.017-1.03), those in WHO stage I (aRR: 1.03; 95%CI: 1.01-1.04), those in WHO stage II (aRR: 1.02; 95%CI: 1.00-1.04), and those who ever received a multi-month prescription on ART (aRR: 1.25; 95% CI: 1.23-1.28), while those aged 10-14 years (aRR: 0.98; 95%CI: 0.97-0.99), previously unsuppressed prior to starting DTG (aRR: 0.92; 95%CI: 0.91-0.93), duration on ART more than 24 months (aRR: 0.96; 95%CI: 0.94-0.97), not retained in care (aRR: 0.83; 95% CI: 0.77-0.89), severe malnutrition (aRR:0.77; 95%CI: 0.69-0.94) and coastal zone (aRR: 0.98; 95% CI: 0.96-0.99) were less likely to achieve VLS.

Conclusions: This study showed DTG-based regimens have a good response for both naïve, previously unsuppressed, and suppressed Children and Adolescents Living with HIV (CALHIV) with significant improvement in viral suppression. Improving retention in care and malnutrition might improve VLS and achieve the third '95'.