New federal guidelines recommend common antibiotic for STI treatment

New guidelines from the Centers for Disease Control and Prevention (CDC) for the first time outline which at-risk groups health providers should recommend use a common antibiotic to help prevent the spread of sexually transmitted infections (STIs). 

The recommendations come amid increasing rates of bacterial STIs that threaten the health of millions of Americans. In the past decade, reported STIs have increased 42 percent from 2011 to 2021, with more than 2.5 million cases reported in 2021 alone, according to the CDC. 

Syphilis cases especially increased 17 percent in the past year and 80 percent in the past five years, a separate CDC report found.

Syphilis was nearly eradicated in the 1990s in the U.S., but it’s come roaring back largely due to years of underfunding public health, along with increasing rates of substance use and the mental health crisis.

Studies have shown the so-called doxy PEP regime has led to a decrease in common STIs such as chlamydia, syphilis and gonorrhea. The agency said a 12-month prescription of doxy PEP after a diagnosis could avert about 40 percent of STIs in affected populations. 

The guidelines recommend that health providers offer a single 200-milligram dose of doxycycline to gay and bisexual men who have sex with men, as well as transgender women, to be taken as soon as possible within 72 hours after having unprotected sex. The prescription should account for enough doses on the basis of the person’s anticipated sexual activity until their next visit. 

Ongoing need for doxy PEP should be assessed every 3–6 months, the agency said. Any member of those groups diagnosed with an STI in the past 12 months should receive counseling that doxy PEP can be used as postexposure prophylaxis to prevent these infections. 

The guidance is specific to the populations that would likely benefit the most — gay and bisexual men and transgender women who had an STI in the previous 12 months and were at high risk to get infected again. 

Doxycycline is a common and cheap antibiotic used to prevent infections such as malaria and Lyme disease. It is also the recommended treatment regimen for chlamydia and an alternative treatment for syphilis in non-pregnant patients with severe penicillin allergy or when penicillin is not available. But until recently, it has not been used to prevent STIs. 

Marcus Plescia, chief medical officer for the Association of State and Territorial Health Officials (ASTHO), said local health officials think the guidance has the potential to be a "game changer" by making such a cheap and effective drug more widely accessible.

"Nothing is a panacea but this has the potential to be a real change in our ability to make a difference in the high rates [of STIs] we’re seeing," Plescia said, with the potential to not just slow the increase but to accelerate a decrease.