Contextual Factors Influencing Implementation of HIV Treatment Support Strategies for Female Sex Workers Living with HIV in South Africa: A Qualitative Analysis Using the Consolidated Framework for Implementation Research

Background:Female sex workers (FSWs) face a confluence of multilevel barriers to HIV care. In South Africa, 63% of FSWs are living with HIV and <40% are virally suppressed. The objective of this analysis was to identify implementation determinants of 2 HIV treatment support strategies.Methods:The Siyaphambili trial tested a decentralized treatment provision and an individualized case management strategy aimed to support FSWs living with unsuppressed HIV viral loads. We identified a nested sample of trial participants using maximum variation sampling (n = 36) as well as a purposively selected sample of implementors (n = 12). We used semistructured interview guides, developed using the Consolidated Framework for Implementation Research (CFIR) and deductively coded the transcripts using CFIR, systematically assessing the strength and valence of implementation. We compared construct ratings to determine whether any constructs distinguished implementation across strategies.Results:Across 3 CFIR domains (innovation characteristics, inner setting, and outer setting), 12 constructs emerged as facilitating, hindering, or having mixed effects on strategy implementation. The relative advantage, design, adaptability, and complexity constructs of the innovation characteristics and the work infrastructure construct of the inner setting were strongly influential (±2 or +2). While the majority of construct valence and strength rating (9-12) were not distinguishing across strategies, we observed 3 weakly distinguishing CFIR constructs (relative advantage, complexity, and available resources).Conclusions:Given the potential benefits of differentiated service delivery strategies, identifying the relative importance of implementation determinants facilitates transparency and evaluation, supporting future strategy design and implementation. Optimizing implementation will support addressing inequities in HIV care and treatment services.