US health officials are set to endorse guidelines for the use of an antibiotic morning-after pill to curb sexually transmitted infections (STIs). The Centers for Disease Control and Prevention (CDC) has released proposed guidelines for the use of doxycycline post-exposure prophylaxis (Doxy-PEP) to decrease bacterial infections such as chlamydia, gonorrhea, and syphilis in populations at highest risk. The recommended treatment involves taking a 200-milligram dose of doxycycline within 72 hours of unprotected sexual contact, followed by routine screening. The guidelines would initially only apply to gay or bisexual men and transgender women who have either previously contracted an STI or are at higher risk. Dr. Jonathan Mermin, director of the CDC's National Center for HIV, Viral Hepatitis, STD, and TB Prevention, described Doxy-PEP as a "game-changing innovation" and a major step in the right direction for STI prevention. Although evidence of its effectiveness in other populations is limited, further research could lead to the expansion of the treatment's recommended use. The CDC plans to finalize the guidelines after a 45-day period for public commentary.

The recommendation for Doxy-PEP comes in response to a surge in STIs in the US. CDC data from 2021 showed a 28% increase in gonorrhea cases and a 74% increase in syphilis cases. In New York City alone, health officials reported a significant rise in STIs following lockdowns during the pandemic, with chlamydia cases up by 9%. The emergence of drug-resistant gonorrhea also poses a public health threat. However, concerns have been raised about Doxy-PEP potentially exacerbating antibiotic resistance. The CDC plans to monitor potential resistance to both STI and non-STI bacteria.

The draft recommendations suggest that doctors should consider prescribing a 200-milligram dose of doxycycline to patients who may have been exposed to STIs through sexual contact. The CDC's draft recommendations are currently limited to gay, bisexual, and other men who have sex with men, as well as transgender women. Specifically, the recommendations apply to individuals who have been diagnosed with at least one bacterial STI in the past year, such as gonorrhea, chlamydia, or syphilis. The recommended dose should be taken as soon as possible, within 72 hours of sexual contact. While the guidelines acknowledge the potential effectiveness of the antibiotic in other populations, the CDC has not issued a firm recommendation for or against broader use. More data is needed before making such recommendations.

Despite the CDC's draft recommendations, many health departments and sexual health clinics have already started offering Doxy-PEP. The National Coalition of STD Directors lists 10 agencies and organizations that have published policies and guidance on Doxy-PEP, including state health departments in California, Michigan, and New Mexico. These organizations have been eager for the CDC's official endorsement, which could pave the way for coverage of the medication's costs through public health budgets and insurance companies. Doxycycline is a relatively inexpensive drug that has been available for many years, making it more accessible compared to some HIV medications.

Implementing Doxy-PEP does come with considerations and potential costs for clinics. The CDC's guidance recommends that doctors prescribe enough doxycycline to last until the patient's next follow-up visit. Doctors should also monitor for potential side effects and screen for breakthrough infections every 3 to 6 months. The concern of antibiotic resistance has been raised, as widespread use of Doxy-PEP could lead to resistance among other pathogens beyond STIs. The CDC plans to monitor the real-world implementation of Doxy-PEP and track any potential drug resistance.

Dr. Mermin emphasized the importance of ongoing monitoring, evaluation, and further studies to update the guidelines as needed. The guidelines will remain open for public comment for 45 days, and a final version is expected to be published in the first quarter of the following year. The endorsement of Doxy-PEP by the CDC could have a significant impact on STI prevention efforts and help address the ongoing epidemic of STIs in the US.