(P453) Barriers and Facilitators of Syphilis Vaccine Trial Participation: A Qualitative Analysis to Inform Trial Design and Community Engagement in the United States

Background: As progress accelerates towards a syphilis vaccine, understanding stakeholder perspectives regarding vaccine development is important to help anticipate organizational, social, and ethical issues which may impact participation in clinical trials. This study examined barriers and facilitators of participation in syphilis vaccine trials among priority groups for early phase vaccine studies.

Methods: We conducted audio-recorded interviews over Zoom with English-speaking individuals > 18 years old recruited from an infectious disease clinic, STI testing site, online research database, and HIV community advisory boards in North Carolina, USA from April 2021 – June 2022. Eligibility criteria included STI diagnosis within 12 months, people living with HIV (PLWH), men who have sex with men, or people who exchange sex for money/drugs. The semi-structured interview guide examined views on a future syphilis vaccine, trial participation barriers/facilitators, and community involvement in vaccine research. Demographic data were collected via post-interview online survey. Interviews were transcribed verbatim and coded using MAXQDA software by two independent coders, followed by thematic analyses of coded data using a socioecological model.

Results: We interviewed 30 individuals in total, including 8 (27%) women, 13 (43%) Black/African American individuals, 19 (63%) PLWH, and 19 (63%) with a previous STI. While 19 (63%) participants indicated immediate interest in future syphilis vaccine trial participation, 10 (33%) noted participation would depend on trial parameters; one person expressed no interest. Trial participation barriers included physical risks of the vaccine and time commitments, two barriers commonly reported in preventative vaccine literature; however, negative interpersonal research relationships also were identified as a barrier. Facilitators included advancing science and syphilis prevention, but also factors relevant to informing trial design and conduct, including positive research relationships and a perception of safety regarding trial procedures and syphilis as a curable infection. Participants emphasized the importance of community involvement to inform vaccine trials given stigmas surrounding syphilis, lack of knowledge about syphilis, and the impact of its sordid research history on community trust.

Conclusions: While stakeholders expressed strong interest in a syphilis vaccine, community engagement on syphilis and syphilis vaccine research is crucial. Further mixed methods research is needed to inform syphilis vaccine trials.