Sexually transmitted infections after implementation of doxycycline postexposure prophylaxis

Area of Science:

• Public Health
• Infectious Diseases
• Clinical Trials

Background:

• Doxycycline postexposure prophylaxis (DoxyPEP) has demonstrated high efficacy in clinical trials for preventing bacterial sexually transmitted infections (STIs).
• Evaluating DoxyPEP's real-world impact among pre-exposure prophylaxis (PrEP) users is crucial for public health strategies.

Purpose of the Study:

• To assess the impact of DoxyPEP on chlamydia (CT), gonorrhoea (GC), and syphilis incidence in San Francisco PrEP users.
• To evaluate DoxyPEP's effectiveness in a clinical setting outside of controlled trial parameters.

Main Methods:

• A cohort study comparing DoxyPEP users and non-users within a sexual health clinic.
• Utilized interrupted time series analysis to evaluate STI incidence rates before and after DoxyPEP implementation.
• Included STI testing for GC, CT, and syphilis across three sites.

Main Results:

• DoxyPEP initiation was associated with significantly lower incidence rates for any STI, CT, and syphilis.
• No significant impact was observed on gonorrhoea (GC) incidence.
• Controlled interrupted time series analysis confirmed a significant decline in overall STI incidence post-DoxyPEP implementation.

Conclusions:

• DoxyPEP uptake was high among PrEP users, indicating strong demand in a clinical setting.
• The intervention demonstrated a rapid and significant decline in STI incidence in a real-world setting.
• Ongoing monitoring of DoxyPEP's impact, adherence, and effects on bacterial STIs is recommended as its use expands.