Characteristics of Kenyan women using HIV PrEP enrolled in a randomized trial on doxycycline postexposure prophylaxis for sexually transmitted infection prevention

INTRODUCTION: The global incidence of sexually transmitted infections (STIs) has been rapidly increasing over the past decade, with more than one million curable STIs being acquired daily.

Young women in sub-Saharan Africa have a high prevalence and incidence of both curable STIs and HIV.

The use of doxycycline as a prophylaxis to prevent STIs is promising; however, clinical trials, to date, have only been conducted among men who have sex with men (MSM) in high-income settings.

We describe the characteristics of participants enrolled in the first trial to determine the efficacy of doxycycline post-exposure prophylaxis (PEP) to reduce STI incidence among women taking daily, oral HIV pre-exposure prophylaxis (PrEP).

METHODS: This is an open-label 1:1 randomized clinical trial on the efficacy of doxycycline PEP compared with standard of care (e.g., quarterly STI screening and treatment) to reduce incident bacterial STIs – Neisseria gonorrhoeae, Chlamydia trachomatis, and Treponema pallidum – among Kenyan women aged ≥18 and ≤30 years.

All were also taking HIV pre-exposure prophylaxis (PrEP).

We describe the baseline characteristics, STI prevalence, and STI risk perception of participants.

RESULTS: Between February 2020 and November 2021, 449 women were enrolled.

The median age was 24 years (IQR 21–27), the majority were never married (66.1%), 370 women (82.4%) reported having a primary sex partner, and 33% had sex with new partners in the three months prior to enrolment.

Two-thirds (67.5%, 268 women) did not use condoms, 36.7% reported transactional sex, and 43.2% suspected their male partners of having sex with other women.

Slightly less than half (45.9%, 206 women) were recently concerned about being exposed to an STI.

The prevalence of STIs was 17.9%, with C. trachomatis accounting for the majority of infections.

Perceived risk of STIs was not associated with the detection of an STI.

CONCLUSION: Young cisgender women using HIV PrEP in Kenya and enrolled in a trial of doxycycline postexposure prophylaxis had a high prevalence of curable STIs and represent a target population for an STI prevention intervention.