CDC Recommends Doxycycline PEP to Prevent STIs

Earlier this week, the Centers for Disease Control and Prevention (CDC) published a draft guidance for the use of doxycycline, a common antibiotic, as a post-exposure prophylaxis (PEP) treatment to prevent sexually transmitted infections (STIs) in individuals who have had unprotected sex. While the guidance is not finalized, experts anticipate a formal recommendation will be issued after the 45-day public commentary period, which will close on November 16, 2023.

According to the organization, new guidelines will provide insight into how doxycycline can be used as part of a broader comprehensive sexual health approach to prevent the spread of bacterial STIs.

These guidelines are supported by findings from an NIH-funded study published in the New England Journal of Medicine earlier this year, which reported that doxycycline PEP reduces STI rates by approximately two-thirds.

The open-label randomized clinical trial focused on men who have sex with men (MSM) and transgender women, giving the experimental group 200 mg of doxycycline within 72 hours of unprotected sex. Those in the control group had an STI infection rate of 31.9%, while those on doxycycline PEP had a significantly lower infection rate of 10.7%.

More specifically, doxycycline would be used to minimize the risks of gonorrhea, chlamydia, and syphilis caused by Neisseria gonorrhoeae, Chlamydia trachomatis, and Treponema pallidum. Based on the NEJM study, doxycycline PEP reduced the risk of these infections by 55%, 88%, and 87%, respectively.

Although doxycycline PEP may be effective at preventing sexually transmitted infections, there are broader public health considerations for updating the standards of care. An increase in antibiotic prescriptions also increases the probability of emerging antibiotic-resistant strains of these infections.

“On an individual and population level, drug resistance will likely occur with the increased use of Doxy PEP, especially with the amount of doxycycline that will be indicated for many users. The extent to which this happens, and the impact, are still open questions and must be carefully monitored,” wrote Hyman Scott, MD, MPH, in an article for the San Francisco AIDS Foundation.

As the CDC determines how to finalize these guidelines and how to mitigate any potential risks, the public can provide written commentary. The CDC is also asking for insight on the following factors:

• The risks and benefits of doxycycline PEP and whether it warrants the recommendations
• The clarity of the proposed guidelines
• The potential impact of guidance on STI rates and prevention
• How the procedures can be effectively implemented in the target population