The early-stage comprehensive costs of routine PrEP implementation and scale-up in Zambia

Introduction: Pre-exposure prophylaxis (PrEP) is effective at preventing HIV infection, but PrEP cost-effectiveness is sensitive to PrEP implementation and program costs. Preliminary studies indicate that, in addition to direct delivery cost, PrEP provision requires substantial demand creation and user support to encourage PrEP initiation and persistence. We estimated the cost of providing PrEP in Zambia through different PrEP delivery models. Methods: Taking a guidelines-based approach for visits, labs and drugs assuming fidelity to the expanded 2018 Zambian PrEP guidelines, we estimated the annual cost of providing PrEP per client for five delivery models: one focused on key populations (men-who-have-sex-with-men (MSM) and female sex workers (FSW), one on adolescent girls and young women (AGYW), and three integrated programs (operated within the HIV counselling and testing service at primary healthcare centres). Program start-up, provider, and user support costs were based on program expenditure data and number of PrEP sites and clients in 2018. PrEP clinic visit costs were based on micro-costing at two PrEP delivery sites (in 2018 USD). Results: The annual cost per PrEP client varied greatly by program type, from $394 (AGYW) to $760 in an integrated program. Cost differences were driven largely by volume (i.e. the number of clients initiated/model/site) which impacted the relative costs of program support and technical assistance assigned to each PrEP client. Direct service delivery costs, including staff and overheads, labs and monitoring, drugs and consumables ranged narrowly from $208-217/PrEP-user. Service delivery costs were a key component in the cost of PrEP, representing 36-65% of total costs. Reductions in service delivery costs per PrEP client are expected with further scale-up. Conclusions: The results show that, even when integrated into full service delivery models, accessing vulnerable, marginalised populations at substantial risk of HIV infection is likely to cost more than previously estimated due to the programmatic costs involved in community sensitization and user support. Improved data on individual client resource usage (e.g. drugs, labs, visits) and outcomes (e.g. initiation, persistence) is required to get a better understanding of the true resource utilization, cost and expected outcomes and annual costs of different PrEP programs in Zambia.