Bacterial sexually transmitted infections (STIs) such as syphilis, chlamydia, and gonorrhea, remain a critical global public-health challenge, particularly in populations with high-risk behaviors. This systematic review and meta-analysis sought to synthesize evidence on the efficacy of doxycycline post-exposure prophylaxis (DoxyPEP) in preventing bacterial STIs, comparing it with other interventions or no prophylaxis, with a focus on high-risk subgroups. This systematic review and meta-analysis assessed DoxyPEP efficacy in preventing STIs versus other interventions or no prophylaxis, focusing on highly vulnerable subgroups (individuals with multiple partners and frequent sexual activity), following PRISMA 2020 and PICO criteria. Two randomized clinical trials (2019–2024) were included, totaling 994 participants (586 experimental, 408 control) and 224 STI events. Meta-analysis was conducted using the ‘meta’ package in RStudio. The pooled analysis (k = 2; n = 994; 224 events), fixed-effects model, showed a 55% risk reduction for STIs (RR = 0.4458; 95% CI: 0.3548–0.5600; z = −6.94; p < 0.0001), with high heterogeneity (I² = 96.6%; τ² = 0.8778; Q = 29.83; p < 0.0001). The fixed-effects approach was justified by behavioral similarity of subgroups: Stewart et al. (2023) evaluated Kenyan women with multiple partners; Molina et al. (2024) studied French men who have sex with men (MSM) with high sexual activity – both with frequent exposure to non-steady partners. Subgroup findings highlighted disparities: among MSM, DoxyPEP reduced chlamydia/syphilis incidence by 83% (HR = 0.17; 95% CI: 0.12–0.26; p < 0.0001), but with increased tetracycline resistance in N. gonorrhoeae . Among Kenyan women, no significant reduction was observed (RR = 0.88; 95% CI: 0.60–1.29; p = 0.51), possibly due to low adherence. DoxyPEP shows substantial efficacy in high-risk subgroups such as MSM, supporting its clinical utility in populations with aligned behavioral patterns. However, subgroup disparities and the small number of studies underscore the need for adapted strategies, such as telemedicine to monitor adherence, and for measures to mitigate bacterial resistance.
Teodosio et al. (Sun,) studied this question.