(P309) Drivers of wanting to use antibiotic pre-exposure prophylaxis for STI prevention among gbMSM in British Columbia, Canada

Background: Gay, bisexual and other men who have sex with men (gbMSM) experience high rates of sexually transmitted infections (STIs). Novel assessments of the antibiotic doxycycline have demonstrated high efficacy and acceptability as pre-exposure prophylaxis (PrEP) for reducing STIs. As interest in clinical implementation grows, there is a need to understand patient variables that facilitate uptake. We aimed to determine the prevalence and correlates of wanting to take STI-PrEP among gbMSM in British Columbia (BC), Canada.

Methods: Using the online Sex Now survey, gbMSM aged 15+ were recruited through sociosexual networking apps and social media advertisements from 11/2019—02/2020. Participants provided demographic details pertaining to sexual behaviours, STI history, and HIV-PrEP use. They then responded to a module on STI-PrEP, created using the theory of planned behaviour. Bivariate logistic regression assessed variables associated with wanting to take STI-PrEP.

Results: Among 296 participants, 97 (32.7%) wanted to take STI-PrEP. Participants were mostly white (77.8% [228/293]), with a mean age of 39.1 years. Those with >10 sexual partners in the previous six months experienced higher odds of wanting to take STI-PrEP (odds ratio [OR] 2.89, 95% confidence interval [CI] 1.61, 5.18). Odds of wanting to take STI-PrEP were elevated for participants who were single (OR 2.76, 95% CI 1.31, 5.85) or in open relationships (OR 4.23, 95% CI 1.96, 9.13), compared with monogamous participants. Those with a history of using HIV-PrEP had higher odds of wanting to take STI-PrEP (OR 3.00 95% CI 1.76, 5.14). Participants with past-year diagnoses of syphilis (OR 7.20, 95% CI 1.47, 35.4) or gonorrhea (OR 2.62, 95% CI 1.25, 5.47) had increased odds of wanting to take STI-PrEP. Those who reported condomless anal sex in the previous six months had elevated odds of wanting to take STI-PrEP (OR 2.08, 95% CI 1.26, 3.44). There were no associations with age, HIV status, or past-year chlamydia diagnosis and wanting to take STI-PrEP.

Conclusion: Individuals with more sexual partners, previous STIs, histories of PrEP use and condomless anal sex had higher odds of wanting to take STI-PrEP. Understanding STI-PrEP desirability helps inform clinical indications, economic analyses and public health planning.