A study published in the New England Journal of Medicine represents the first clinical trial to test whether doxycycline postexposure prophylaxis (PEP) would prevent sexually transmitted infections (STIs) among cisgender women. Researchers considered 224 subjects assigned to a doxycycline-PEP group and 225 to a standard-care group over 12 months. A total of 109 incident STIs occurred: 50 in the doxycycline-PEP group and 59 in the standard-care group. Chlamydia accounted for 85 of the STIs (78%) with 35 occurring in the doxycycline-PEP group and 50 in the standard-care group. The authors in this study concluded that the incidence of STIs was not significantly lower with doxycycline PEP than with standard care among cisgender women. The analysis also found only about one-third of the hair samples in the doxycycline-PEP group showed evidence that the participants were taking doxycycline.
More work to be done: Typically, “doxy-PEP” is recommended for men who have sex with men and transgender women, so understanding the potential to apply postexposure prophylaxis to larger populations has merit.