Integrated Health Services (IHS): A Structural Intervention to Improve HIV/STI Screening and PrEP Navigation in Primary Care

The goal of this clinical trial is to learn whether integrating routine, opt-out HIV and STI testing and pre-exposure prophylaxis (PrEP) navigation into primary care increases use of these services among adults ages 18 to 45 receiving care at Federally Qualified Health Centers in Mississippi. The main questions it aims to answer are: 1. Does the integrated model increase HIV and STI testing compared with standard care? 2. Does the integrated model increase PrEP navigation activity for eligible patients? 3. How do patients and clinic staff experience the integrated model in terms of satisfaction, comfort discussing sexual health, and feasibility in daily workflows? Researchers will compare a standard-care period to a period when the integrated model is in place to see if the integrated model improves service use and patient experience. Participants will: 1. Receive usual primary care, with HIV/STI testing and PrEP discussions offered as a routine, opt-out part of care during the integrated period 2. Be invited, if eligible, to complete a brief survey about their clinic experience 3. For staff, be invited to take part in a short survey or interview about clinic workflows and the integrated model