ECDC Issues New Guidance: Doxycycline for STI Prevention

For more than a decade, a concerning increase in bacterial STIs has been seen in the EU/EEA, as notifications for gonorrhoea, syphilis, and chlamydia have risen sharply, with men who have sex with men being disproportionately affected. In 2023, notification rates increased by 16% for chlamydia, 138% for gonorrhoea, and 53% for syphilis compared to 2019 levels. Doxy-PEP has emerged as a potential prevention strategy, which involves taking a single 200 mg dose of doxycycline within 24 hours, and no later than 72 hours, after condomless sexual contact. Clinical trials have demonstrated that doxy-PEP is effective in reducing the incidence of chlamydia and syphilis among men who have sex with men and transgender women with a history of STIs. However, doxy-PEP is unlikely to effectively reduce the incidence of gonorrhoea in most European settings, due to pre-existing high levels of tetracycline resistance in Neisseria gonorrhoeae strains currently circulating in the EU/EEA, which was reported at 58.4% in 2023. ECDC’s guidance evaluates the current evidence on the efficacy of this intervention alongside potential public health risks. A primary concern raised is the potential for doxy-PEP to accelerate the development of antimicrobial resistance (AMR). Evidence suggests that widespread use could lead to increased resistance not only in STI pathogens but also in other bacteria, such as Staphylococcus aureus, and commensal organisms (bacteria that naturally live on or in the body without causing harm) within the human microbiome. This poses a risk to both individual users and the wider community. Based on these findings, ECDC does not recommend doxy-PEP as a population-level intervention and advises that decisions regarding its use should be made at an individual level, based on the individual risk of infection as assessed by a clinician. If doxy-PEP is implemented, it should be focused primarily on the prevention of syphilis. It should be targeted specifically at groups at the highest risk of infection rather than the broader population. In addition, doxy-PEP should not be a standalone measure and must be integrated into a comprehensive sexual health strategy that includes access to regular testing, vaccination, HIV prevention, and partner notification services. Periodic reassessment of individual needs is recommended. Users should be informed about the benefits and potential risks, including the uncertainty regarding long-term safety, and the potential development of antimicrobial resistance. Robust surveillance to monitor the impact of doxy-PEP on STI incidence, antibiotic consumption, and the emergence of antimicrobial resistance is essential.