CDC advises doxycycline for STI prevention post-exposure

The Centers for Disease Control and Prevention (CDC) has advised that certain individuals take the antibiotic doxycycline to help prevent sexually transmitted infections (STIs) in cases of potential exposure. Doxycycline, which is commonly used to treat conditions like acne, malaria, and Lyme disease, has now been recommended for use among gay and bisexual men as well as transgender women in the United States. This recommendation is particularly for those who have had unprotected sex, as a strategy to prevent STIs.

The treatment, known as post-exposure prophylaxis (PEP), involves a 200 mg dose of doxycycline. This dose should be taken within 72 hours after unprotected oral, vaginal, or anal sex. The recommendation comes in response to the rising number of infections such as syphilis, gonorrhea, and chlamydia in the United States, which are notably affecting men who have sex with men and transgender women.

Research has supported this recommendation. According to the CDC, three clinical trials have indicated that using doxycycline as post-exposure prophylaxis can significantly reduce the risk of contracting syphilis or gonorrhea by over 70%, and it can lower the risk of chlamydia by 50%. Doxycycline is available in pill form and should be limited to a single 200 mg dose within a 24-hour period, a regimen referred to as doxy PEP. This method is similar to post-exposure regimens used for HIV prevention.

The CDC suggests that individuals who are at risk should obtain prescriptions for doxycycline so they can administer it themselves as soon as possible following unprotected sex. The guidelines also recommend that those using doxy PEP undergo regular bacterial STI testing and be reassessed every three to six months to ensure the treatment's effectiveness and safety.

The need for this new recommendation is underscored by troubling statistics. In 2022, the United States reported over 2.51 million cases of syphilis, gonorrhea, and chlamydia, a significant increase from 2.37 million cases in 2017. Syphilis, which was nearly eradicated two decades ago, has seen a particularly alarming rise, with infections increasing by 79% from 2018 to 2022. During the same period, gonorrhea infections saw an 11% increase.

The CDC's recommendation for doxycycline as post-exposure prophylaxis aims to address these rising rates of STIs and provide a proactive measure for those most at risk. By implementing this strategy, the agency hopes to curb the spread of these infections and protect public health, particularly among communities that are disproportionately affected.