To investigate the effects of doxycycline pre- and post-exposure prophylaxis (doxy-PrEP/PEP)
on bacterial sexually transmitted infections (STIs) by conducting a systematic review
and meta-analysis.PubMed, Embase, and CENTRAL were searched for randomised controlled
trials (RCTs), including ongoing studies published until 7 November 2023. Our primary
endpoint was the incidence of bacterial STIs measured as the number of visits with
an STI per total number of visits. Random-effects model was used to estimate pooled
effect sizes. The study was registered with PROSPERO, CRD42023478486.We identified
six eligible studies containing data from seven articles and four conference abstracts,
enrolling men who have sex with men (MSM), transgender women (TGW) and cisgender women
(CGW). The pooled analysis of 1,766 participants with 602 newly diagnosed STIs showed
a 56% decrease in the overall STI incidence using doxy-PrEP/PEP (RR=0.44; 95%CI: 0.30-0.65;
I2=73%). For doxy-PEP, including MSM and TGW only, the RR observed for overall STI
incidence was 0.40 (95%CI: 0.28-0.57; I²=37%), 0.19 (95%CI: 0.08-0.44; I²=39%) for
chlamydia, 0.23 (0.14-0.36; I²=0%) for syphilis and 0.55 (95%CI: 0.34-0.87; I²=41%)
for gonorrhoea. No serious adverse were reported in the studies. The certainty of
evidence regarding the efficacy of doxy-PEP among MSM and TGW was graded as high.Doxy-PEP
significantly reduces the number of new cases of chlamydia and syphilis and is potentially
effective against gonorrhoea, influenced by local resistance patterns. Thus, it is
a promising tool in the prevention of bacterial STIs among MSM and TGW.
