Factors Associated With Willingness to Use Daily Antibiotics as Sexually Transmitted Infection Prophylaxis Among HIV Preexposure Prophylaxis-Experienced Gay and Bisexual Men in Australia.

Background: Gay and bisexual men (GBM) who use HIV preexposure prophylaxis (HIV-PrEP) have high rates of bacterial sexually transmitted infections (STIs). The use of daily antibiotics as STI preexposure prophylaxis (STI-PrEP) may be appealing to GBM who are using or have previously used HIV-PrEP (HIV-PrEP-experienced) for the prevention of bacterial STIs.

Methods: We examined willingness to use daily STI-PrEP among a cross-sectional sample of HIV-PrEP-experienced GBM in Australia who participated in an observational online cohort study from August 2018 to March 2020. Factors associated with willingness to use daily STI-PrEP were determined using bivariate and multivariate logistic regression.

Results: Of the 1347 participants, half (54.3%) were willing to use daily STI-PrEP. Factors independently associated with greater willingness to use daily STI-PrEP included having >10 sexual partners in the last 6 months, using methamphetamine in the last 6 months, being more conscious about avoiding STIs, having a greater number of STIs since commencing HIV-PrEP, being willing to take HIV-PrEP for as long as they were at risk of acquiring HIV, and only using condoms when a sexual partner requested them. Conversely, factors associated with less willingness to use daily STI-PrEP included being university educated, using nondaily dosing regimens of HIV-PrEP, preferring event-driven HIV-PrEP, and being concerned about long-term HIV-PrEP adverse effects.

Conclusions: Sexually transmitted infection PrEP is likely to be appealing to many HIV-PrEP-experienced GBM, especially those who engage in activities associated with a higher risk of STI transmission. However, they are less likely to be willing to use STI-PrEP unless it aligns with their HIV-PrEP dosing regimen, suggesting that research into the safety and efficacy of alternative STI prophylaxis dosing options should be prioritized.