Use of doxycycline post-exposure prophylaxis and factors associated with its adoption in the men who have sex with men community in Hong Kong: a cross-sectional study

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Objectives This study aims to investigate the prevalence of doxycycline post-exposure prophylaxis (doxy-PEP) use and identify factors associated with its uptake in the men who have sex with men (MSM) community in Hong Kong, where clinical guidance is not in place. Methods MSM aged 18 years or above were recruited from February through October 2025 in Hong Kong. A self-administered online survey was used to collect data on socio-demographics, sexual behaviours, histories of sexually transmitted infections and use of doxy-PEP and HIV pre-exposure prophylaxis (PrEP). Guided by Andersen’s behavioural model, predisposing, enabling and need factors were identified, and their associations with recent doxy-PEP use (past 6 months) were examined using a multivariable binary logistic regression model. Results A total of 406 MSM with a median age of 35 years completed the survey, of whom 5 reported living with HIV. Overall, 15% (N=61) had ever used doxy-PEP and 10% (n=41) reported recent use. For predisposing factors, older MSM were less likely (adjusted odds ratio (aOR)=0.94, 95% CI 0.89 to 0.99), but bisexual MSM were more likely (aOR=3.22, 95% CI 1.38 to 7.48) to report recent doxy-PEP use. Among enabling factors, HIV PrEP use (aOR=3.43, 95% CI 1.41 to 8.37) in the past 6 months was the only variable associated with recent doxy-PEP use. Need factors including engagement in group sex (aOR=2.72, 95% CI 1.07 to 6.88) and chemsex (aOR=3.65, 95% CI 1.27 to 10.43) were associated with recent doxy-PEP use. Conclusions This study revealed high awareness and a moderate rate of doxy-PEP use among the MSM community, despite the lack of recommended guidance. MSM who are younger, bisexual, have engaged in chemsex or group sex or have prior experience with HIV PrEP use may need to be specifically considered when developing future guidelines on doxy-PEP use.