Treatment outcomes among children younger than five years living with HIV in rural Zambia, 2008–2018: a cohort study

BACKGROUND: HIV testing and treatment guidelines for children in sub-Saharan Africa have evolved over time, such that children are now treated at younger ages. The objective of this study was to describe the treatment experience for immunologic, virologic, and growth outcomes among HIV-infected Zambian children younger than 5 years of age from 2008 to 2018. METHODS: Participants enrolled in a clinical cohort study in Macha, Zambia and initiating antiretroviral treatment before 5 years of age between 2008 and 2015 were included in the analysis and followed up to the end of 2018. Outcomes, including growth, CD4+ T-cell percentage, viral suppression, and mortality, were evaluated among all children using longitudinal and survival analyses. Comparisons by age at treatment initiation (< 1, 1 to < 2, and 2 to < 5 years) were also evaluated. RESULTS: Three hundred eighty-one children initiating treatment before 5 years of age between 2008 and 2015 were included in the analysis. Growth metrics and CD4+ T-cell percentage improved over time after treatment initiation. However, 20% of children remained underweight and 40% of children remained stunted after the first 36 months of treatment. 85% of children had a viral load < 400 copies/mL after 12 months of treatment. However, children < 1 year at treatment initiation were more likely to have a detectable viral load in the first 12 months of treatment and less likely to achieve viral suppression compared to older children. Mortality was highest in the first 12 months of treatment, among underweight children, and among children initiating treatment in 2008–2010 compared to 2011–2015. CONCLUSIONS: Most children initiating antiretroviral treatment from 2008 to 2015 in rural Zambia responded well to treatment. However, many children remained underweight and stunted, and experienced high mortality rates during the first few months of treatment. This supports continued efforts to improve early infant diagnosis, nutritional support, and pediatric drug formulations. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12887-021-02793-y.