Recent research has suggested that post-exposure doxycycline may be an effective way to reduce the risk of some sexually transmitted infections (STIs) for men who have sex with men and trans women. Studies have indicated that a single dose of doxycycline taken within 72 hours of unprotected sex can reduce the incidence of syphilis, chlamydia and gonorrhea. The Centers for Disease Control and Prevention is currently reviewing the research, and has recommended that healthcare providers offer doxycycline for prevention to those groups for whom it is most effective.
The antibiotic has not been found to reduce the incidence of STIs in cisgender women, and there is a potential risk of antibiotic resistance associated with widespread use. The C.D.C. is expected to make further recommendations on the use of post-exposure doxycycline in the near future.
Overall, this research has the potential to reduce the risk of some bacterial STIs in at-risk populations. However, it is important to note that doxycycline does not provide protection against viral STIs, and that the use of condoms and other barrier methods are still the best way to prevent the transmission of all STIs.