WHO early warning indicators of HIV drug resistance in children and adolescents living with HIV in Cameroon: a pre- and post-COVID-19 analysis

COVID-19 disrupted global health service delivery, particularly among children and adolescents living with HIV (CALHIV), increasing the risk of poor treatment adherence. This study assessed the impact of the COVID-19 pandemic on WHO-recommended early warning indicators (EWIs) of HIV drug resistance (HIVDR) among CALHIV. We conducted a descriptive, longitudinal, retrospective study among children (0-9 years) and adolescents (10-19 years) receiving antiretroviral therapy (ART) in five health facilities in the Littoral region of Cameroon. Seven EWIs were monitored: ART attrition, viral load (VL) suppression, VL coverage, appropriate second VL, ARV medicine stock-outs, antiretroviral drug refills at the pharmacy, and appropriate switch to second-line ART. EWI were collected from January 2018 to December 2021 and classified as "poor," "fair," or "desirable" according to WHO criteria. Trend analyses were performed using Pearsons Chi-squared test with Yates correction in R (version 4.1.1). In 2021, 817 participants were included, comprising 214 children and 603 adolescents. Overall performance was poor for most EWIs in both age groups, except for ART attrition and VL coverage, which showed desirable performance across years. A slight improvement in most indicators was observed between 2018 and 2019, followed by a significant decline in 2020 (p<0.001), coinciding with strict COVID-19 restrictions, and a subsequent improvement in 2021 (p<0.01) as mitigation measures were eased. Despite this recovery, children consistently experienced worse outcomes, including higher ART attrition (9.4% vs 4.4%, p<0.05), lower VL suppression (75.3% vs 82.1%, p<0.05), and poorer access to confirmatory VL testing (15.1% vs 69.5%, p<0.001). Overall, the COVID-19 pandemic negatively affected HIV service delivery during its early phase, although the health system demonstrated adaptive capacity one year later. Targeted public health actions are therefore needed to prevent their long-term effects and improve treatment outcomes in this vulnerable population, especially among children.