Over-the-Counter PrEP: Acceptability, Feasibility, and Potential Impact of Access without a Prescription (OFFSCRIPT) - PROJECT SUMMARY The population-level impact of HIV preexposure prophylaxis (PrEP) has been limited by barriers to access. People face challenges with attending frequent clinical visits, completing laboratory monitoring, and disclosing sexual or substance use behaviors to providers, deterring PrEP initiation and continuation. These barriers to PrEP access and use could be alleviated by making PrEP available over the counter (OTC). If PrEP were OTC, it could be conveniently accessed without provider visits, laboratory-based testing, or their associated costs. People would no longer need to disclose behaviors to clinicians, easing access for all but particularly for populations experiencing stigma in healthcare settings, such as Black men who sex with men (MSM). Home- based HIV tests, which are available OTC and acceptable in priority populations, could be bundled with OTC PrEP: envision self-checkout at a retail pharmacy or online with a 3-month PrEP package containing 90 pills and an HIV test. However, for OTC PrEP to be acceptable and feasible from a clinical and regulatory perspective, the benefits of increased access, such as reductions in HIV incidence, would need to outweigh the potential risks of reduced monitoring, such as increases in HIV drug resistance and other adverse clinical outcomes. Moreover, for OTC PrEP to have a meaningful impact on HIV incidence, priority populations would need to be interested in using it and able and willing to pay for it. Oral contraceptive pills, another medication to prevent an undesired sexual health outcome, were granted OTC status in July 2023 after years of research and strategic partnership building, providing a roadmap for rigorous formative research on OTC PrEP. We propose Over-the-Counter PrEP: Acceptability, Feasibility, and Potential Impact of Access without a Prescription (OFFSCRIPT), a mixed-methods study to assess interest in OTC PrEP in priority populations, explore key stakeholders’ perspectives on acceptability and feasibility, and project long-term effects on health benefits and risks. In Aim 1, we will survey diverse cohorts of cisgender MSM, transgender women, and cisgender women on interest in use of OTC PrEP, reasons for potential use or non-use, and willingness and ability to pay. We will evaluate differences by demographics, including race and ethnicity, and by current and prior PrEP use. In Aim 2, we will conduct focus groups to explore acceptability of OTC PrEP and facilitators and barriers to implementation among key stakeholders, including clinicians, leaders of professional medical organizations, public health officials, regulatory experts, drug and HIV self-test manufacturers, and community advocates. In Aim 3, we will use mathematical modeling to project the long-term impact of the availability of OTC PrEP on population-level outcomes, including HIV incidence, disparities, and adverse clinical events, such as HIV drug resistance, serious renal events, hepatitis B relapse, and sexually transmitted infections. This study will be the first to explore the acceptability, feasibility, and potential impact of OTC PrEP, which could shift the paradigm for PrEP access in the U.S. and thus have a major impact on the HIV epidemic nationally.