Abstract:
South Africa has a large burden of bacterial sexually transmitted infections (STIs) with high
rates among men who have sex with men (MSM). Randomised controlled trials have
recently demonstrated high effectiveness of doxycycline post-exposure prophylaxis (PEP)
for prevention of bacterial STIs in MSM, with 70% – 85% reductions in Chlamydia trachomatis
infection and syphilis, and approximately 50% reduction in Neisseria gonorrhoeae infection.
Doxycycline PEP was not demonstrated to be effective in reducing C. trachomatis and
N. gonorrhoeae infection among Kenyan cisgender women. Although no worrisome trends
in antimicrobial resistance (AMR) were observed in the trials, important concerns remain
about doxycycline PEP and AMR development in STIs, other pathogens, commensals,
and the microbiome. Tetracycline resistance in N. gonorrhoeae is already widespread in
South Africa, but emergence of AMR in other STIs would be concerning. Larger sample
sizes of doxycycline PEP users with longer follow-up time are needed to understand the
impact that doxycycline PEP may have on AMR at individual and population level. In this
opinion article, we weigh the benefits of doxycycline PEP for prevention of bacterial STIs
against the existing AMR concerns and data gaps in the South African context. Based on
the current evidence, we conclude that it would be reasonable to offer doxycycline PEP to
high-risk MSM on a case-by-case basis, provided that it is offered by experienced sexual
health clinicians in settings that have access to diagnostic STI testing and ongoing AMR
surveillance.
