P219: Mpox vaccine uptake and associated factors among transgender people and gay, bisexual and other men clients of an urban sexually-transmitted infection clinic in Vancouver, British Columbia.

Background: Mpox vaccination campaigns for transgender people and gay, bisexual and other men who have sex with men (T/GBM) were the primary public health strategy for controlling the 2022 Mpox outbreak. In British Columbia (BC), Mpox prevention and control measures including vaccination were implemented in close partnership with T/GBM organizations and providers from the start of the outbreak. We measured vaccine uptake and associated factors among T/GBM clients of an urban STI clinic in Vancouver, BC. Methods: We conducted a cross-sectional online survey between August 8-22, 2022, 5-7 weeks following the launch of a first-dose Mpox vaccination campaign targeting T/GBM populations. We invited all STI clinic clients in the past 3 years who consented to be contacted for research. Survey domains included vaccine outcomes, mpox knowledge, beliefs, cues to action, and psychological antecedents of vaccination. Using bivariate analyses we examined whether these factors were associated with vaccine uptake among vaccine-eligible T/GBM. Results: Of 3,930 clients invited, 27% (946) participated in the survey. Of the 331 T/GBM participants: the majority were White, university educated, identified as a man and gay; 10% had trans experience. Overall, 51% had been vaccinated (167/325); 68% (222/326) were eligible for vaccination, of whom 66% (146/222) had been vaccinated. Being unvaccinated was significantly more common among participants identifying as bisexual or heteroflexible/mostly straight, and who spent less time with other T/GBM. Eligible yet unvaccinated participants had lower perceived susceptibility, and reported fewer cues to action (e.g., fewer saw information promoting the vaccine), and increased constraints to vaccine access; vaccine barriers related to accessing clinics and privacy were common. The majority (85%, 64/75) of those eligible and unvaccinated at time of survey were willing to receive the vaccine. Conclusion: In this sample of STI clinic clients, vaccine uptake among eligible T/GBM was high in the initial weeks following a Mpox vaccination campaign. However, uptake was patterned on social gradients with lower uptake among T/GBM who may be less effectively engaged by available promotion channels. Intentional and ongoing engagement of diverse T/GBM groups is key in Mpox and other targeted vaccination programs to this population. [ABSTRACT FROM AUTHOR]