Simplifying PrEP delivery: One-stop service pathway to improve PrEP care efficiency and continuation in Kenya - ABSTRACT Maximizing access and minimizing costs of delivery are key challenges for optimizing the public health impact of HIV pre-exposure prophylaxis (PrEP). Between January 2017 and December 2019, as part of Kenya's national public sector PrEP roll-out, we conducted a stepped-wedge cluster-randomized pragmatic trial to catalyze scale- up of PrEP delivery integrated in 25 public HIV clinics (The Partners Scale Up Project). We demonstrated that PrEP can be delivered in African public health facilities using existing staff: >8000 initiated PrEP (53% women) with reasonable continuation and high adherence among those returning. The study also highlighted major health system barriers including lengthy visits with multiple stops (i.e., separate rooms for triage, HIV testing, counseling, pharmacy) that burden the health system. For healthy HIV uninfected persons, long waiting at the clinic, time away from work, and costs for getting to visits challenge persons taking PrEP. Efficient delivery strategies could reduce costs, potentially improve client engagement and allow services to be available to a larger number of people. In a short-term pilot study jointly funded by NIH and PEPFAR, we tested the feasibility of one-stop PrEP provision (i.e., all PrEP services provided in a single room) at PEPFAR-supported clinics and showed that one-stop service was feasible and highly acceptable to both PrEP users and providers. One-stop significantly shortened wait time (>80%) without reducing provider-client contact time; PrEP initiation stayed stable and there was suggestion of better early continuation and on-time visit attendance, indicating that one- stop PrEP might add efficiencies to PrEP systems, without undermining quality. Building on our learning from the randomized trial and the pilot study, we propose to conduct an effectiveness-implementation cluster- randomized trial of one-stop to assess effectiveness to improve delivery efficiency and continuation on PrEP and to rigorously study health system factors. We will randomize 12 public health facilities with established PrEP programs in Western Kenya 1:1 to recruit and follow 1800 HIV-uninfected persons newly initiating PrEP to test the effectiveness of one-stop care pathway compared to usual care pathway (Aim 1). Within the large program, we will establish a randomly selected nested observational cohort of PrEP users (n=150, including clients who start but discontinue) to study longitudinal HIV prevention behavior, including reasons for discontinuation and how clients align PrEP use with HIV risk. Co-primary outcomes will be continuation and adherence quantified by tenofovir-diphosphate levels in dried blood spots. We will use the Systems Analysis and Proctor's implementation framework to evaluate implementation outcomes at the health system, facility, provider, and client-level (Aim 2). Finally, we will conduct micro costing and time and motion studies to evaluate the costs and model the budget impact and affordability of PrEP program with One-stop model (Aim 3). We have already demonstrated that PrEP can be delivered in Kenyan public facilities by existing staff; this work will extend further, aiming for greater efficiency and cost-saving, reduced provider workload, diminished client burden, and better PrEP continuation.