Improving Choice and Use of Biomedical HIV Prevention for Women in Uganda: A Couples-Based Approach - PROJECT SUMMARY/ABSTRACT The HIV prevention field has realized a long-sought goal to have multiple safe and effective HIV prevention options that offer women the opportunity to choose a pre-exposure prophylaxis (PrEP) product that best fits their needs and preferences. Product attributes across injectable long-acting cabotegravir, dapivirine vaginal ring, and oral PrEP differ considerably, with implications for user experience, adherence requirements, and discreetness. Clinical trials and demonstration projects have highlighted challenges in achieving sustained PrEP use, and decades of research in sub-Saharan Africa (SSA) have underscored the significant role that male partners play in many women’s choice of and ability to consistently use these methods. Although it remains critically important to center women’s agency in choosing options that meet their needs, many women want to involve their partners in these decisions and, in many settings, men influence women’s ability and enable their autonomy to adopt and use prevention effectively. The overall goal of this study is to evaluate the effectiveness and implementation of a couples-based shared decision-making intervention called CUPID (Couples United in HIV Prevention Informed Decisions) within the CATALYST demonstration project in Uganda that offers choice in biomedical PrEP to women. The CUPID intervention will involve delivery of a paper-based, shared decision-making tool in community and clinic settings by peer PrEP ambassadors affiliated with Ministry of Health facilities. CUPID aims to influence multiple PrEP outcomes (uptake, persistence and adherence) through couples’ shared decision making to improve communication about HIV prevention and PrEP options, mutual commitment to HIV prevention within the relationship, and partner support for PrEP use. We will accomplish this by conducting a hybrid type 1 effectiveness-implementation study designed to refine the CUPID intervention for use in public health settings (Aim 1), evaluate its effectiveness in improving PrEP uptake, persistence, and use among Ugandan women (Aim 2), and assess implementation outcomes to inform the adoption and integration of CUPID to support women's PrEP uptake and use (Aim 3). CUPID’s effectiveness in increasing PrEP use by women will be assessed using a multiple baseline interrupted time- series design with randomization of health facilities to intervention start time. Implementation outcomes will assess the acceptability, adoption, feasibility, and fidelity of CUPID using a mixed methods design. The study leverages a real-world implementation partnership with the CATALYST study and the Ugandan Ministry of Health to address the critical question of whether CUPID can optimize women’s PrEP choice and use through male partner support and shared decision-making using a scalable intervention approach. If successful, CUPID will offer a community-based strategy for engaging male partners to support PrEP choice and improve HIV prevention among women.