Abstract
BACKGROUND: The province of British Columbia (BC), Canada, was among the first jurisdictions to scale up HIV Treatment as Prevention (TasP) to the population level, including funding and policy commitments that enhanced HIV testing efforts (e.g., expansion of routine, opt-out testing), while also making antiretroviral therapy universally available to all people living with HIV. As such, BC represents a critical context within which to identify factors that influenced the scalability of TasP (e.g., acceptability, adoption, fidelity, equitable reach, sustainability), including key opportunities and challenges. METHODS: We draw on in-depth, semi-structured interviews with 10 key stakeholders, comprised policymakers at the local and provincial levels and representatives from community-based organizations. Using the Consolidated Framework for Implementation Research (CFIR) to guide data collection, coding, and analysis, we identified key factors that influenced practice transformation and scale up. RESULTS: Key factors that contributed to the successful scale up of TasP included: (i) opportunities that enhanced stakeholder buy-in based on features of the intervention characteristics, including with regard to assessments about the quality and strength of evidence supporting TasP; (ii) an inner setting implementation climate that was, in part, shaped by the large and highly symbolic government investments into TasP; (iii) features of the outer setting such as external policies (e.g., harm reduction) that cultivated opportunities to implement new "systems-level" approaches to HIV intervention; (iv) the personal attributes of some "middle-level" influencers, including a team that was comprised of some highly motivated and social justice-oriented individuals (e.g., folks who were deeply committed to serving marginalized populations); and (v) the capacity to develop various implementation processes that could maintain "nimble and evidence-informed" adaptations across a highly decentralized service delivery system, while also creating opportunities to adapt features of TasP programming based on "real time" program data. CONCLUSION: Constructs across all five domains of CFIR (intervention characteristics, outer setting, inner setting, characteristics of individuals, and process) were identified to influence the success of TasP in BC. Our findings provide important insights into how BC can successfully implement and scale up other systems-level interventions that have demonstrated efficacy, while also offering insights for other jurisdictions that are currently or planning to scale up TasP.