Perceptions of acceptability and preferences surrounding a hypothetical syphilis vaccine in Lima, Peru

Background No vaccine is currently available for syphilis. Research efforts to inform vaccine development are underway. In parallel, understanding factors that would influence willingness to receive a future vaccine can provide useful information for vaccine design and future implementation. This study explored attributes of interest in a hypothetical syphilis vaccine using focus group discussions in Lima, Peru. Methods In early 2025, we conducted ten virtual focus group discussions, among five population groups in Lima, Peru: health professionals, sexual/gender minorities, general population, cisgender female sex workers, and parents of minors. Semi-structured guides explored barriers and facilitators to preventive care, attitudes toward vaccines, syphilis knowledge, and desired attributes of a potential syphilis vaccine. Audio recordings were analyzed thematically. Results Eighty-five participants took part in the discussions. Despite limited syphilis knowledge among many participants, there was interest in a hypothetical vaccine. Acceptability was shaped by three factors including, vaccine attributes, structural conditions and the healthcare provider-user relationship. In vaccine attributes, participants desired high effectiveness, safety, and a single-dose schedule, while expressing concerns about vaccine-induced persistent seropositivity related to stigma about STI prevention. Structural conditions: free vaccination, endorsement from respected health institutions, information environment and health education were viewed as essential for uptake. Third, the healthcare provider–user relationship emerged as a central mediator influencing how individuals interpreted vaccine information and navigated structural barriers. Conclusions Acceptability of a future syphilis vaccine depends not only on its attributes, but also on structural enablers and the quality of provider–user interactions. Strengthening provider communication, addressing structural barriers, and ensuring transparent information dissemination will be essential for equitable implementation.