Frequent chlamydia and gonorrhoea but very infrequent syphilis among men who have sex with men using HIV pre-exposure prophylaxis in West Africa

Abstract

Objectives: Although oral pre-exposure prophylaxis (PrEP) for HIV is being rolled out in West Africa, data on sexually transmitted infections (STIs) in PrEP users are scarce. We assessed the prevalence, incidence and determinants of bacterial STIs in men who have sex with men (MSM) taking PrEP in Burkina Faso, Côte d'Ivoire, Mali and Togo.

Methods: A prospective cohort study among MSM initiating PrEP as part of a comprehensive HIV prevention package was conducted between 2017 and 2021 in community-based clinics in the four study countries. Molecular screening for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) was performed at months 0, 6 and 12. Serological testing for syphilis was performed every 3 months over the first year of follow-up. Determinants of CT and/or NG incidence were identified using Poisson generalised linear mixed models.

Results: A total of 598 participants with a median age of 24.7 years were included. Prevalence of CT and/or NG was 24.4% (95% CI 21.0 to 28.1), 22.4% (95% CI 18.4 to 26.8) and 29.0% (95% CI 24.2 to 34.1) at months 0, 6 and 12, respectively. The prevalence of syphilis ranged from 0.2% (95% CI 0.0 to 0.9) at month 0 to 0.8% (95% CI 0.2 to 2.4) at month 12. Ninety incident CT and/or NG infections occurred during a total follow-up time of 280.6 person-years (incidence rate 32.1 per 100 person-years, 95% CI 25.8 to 39.4). Three incident syphilis infections were detected during a total follow-up time of 459.7 person-years (incidence rate 0.7 per 100 person-years, 95% CI 0.1 to 1.9). CT and/or NG incidence was associated with condomless insertive anal sex (adjusted incidence rate ratio 1.96, 95% CI 1.04 to 3.71, p=0.038).

Conclusions: CT and NG were frequent but syphilis was very infrequent in MSM using HIV PrEP in West Africa. HIV programme managers should integrate STI services into PrEP programmes.

Keywords: Africa; Chalmydia trachomatis; PrEP; gonorrhoea; syphilis.