Estimating the impact of doxycycline post-exposure prophylaxis on antibiotic consumption among men who have sex with men using PrEP in the EU/EEA

BACKGROUNDDoxycycline post-exposure prophylaxis (doxy-PEP) has been shown to reduce the incidence of chlamydia and syphilis among men who have sex with men (MSM) at high risk of sexually transmitted infections (STIs). However, doxy-PEP adds antibiotic exposure and may select for tetracycline resistance in both target and bystander bacteria, raising concerns about antimicrobial resistance (AMR). Quantifying additional antibiotic consumption from doxy-PEP is important for assessing its potential AMR impact at population level.AIMWe estimated the potential increase in doxycycline consumption attributable to doxy-PEP among MSM using HIV pre-exposure prophylaxis (PrEP) in the European Union and European Economic Area (EU/EEA) and compared it with overall doxycycline and tetracycline-class consumption.METHODSWe used Monte Carlo simulation to estimate annual doxycycline use from doxy-PEP among MSM using PrEP. We estimated population size from the 2024 European MSM Internet Survey and derived doxy-PEP uptake and prescribing frequency from expert elicitation. Estimated consumption in defined daily doses (DDD) per year was compared with tetracycline-class and doxycycline antibiotic use reported by the European Surveillance of Antimicrobial Consumption Network.RESULTSDoxy-PEP among MSM using PrEP in the EU/EEA could result in an estimated 4.4 million DDDs of doxycycline annually (95% credible interval (CrI): 0.5-18.1 million), corresponding to a 1.9% increase (95% CrI: 0.2-7.7) relative to 2023 doxycycline consumption.CONCLUSIONThe estimated Doxy-PEP use constitutes a non-negligible share of total doxycycline consumption in the EU/EEA. Monitoring doxy-PEP uptake and AMR indicators will be essential as more countries consider integrating this intervention into STI prevention strategies.