Dec. 9, 2022 — Using antibiotics to prevent — not just treat — sexually transmitted infections was a fringe idea a decade ago. Now, it’s backed by multiple studies and approved by the California Department of Public Health.
Jeffrey Klausner, MD, Infectious Disease Physician and Professor of Public Health, University of Southern California, published The first randomized controlled trial The debate over whether doxycycline — an antibiotic commonly used to treat infections, including syphilis, chlamydia and others — can prevent STIs was made back in 2015. At first, he said the NIH did not want to fund the work, citing potential antimicrobial resistance.
In worst-case scenarios, the microbiome changes over time, no longer responds to the drug, and the treatment stops.
But the growing STI crisis is prompting healthcare professionals to look for new options to help.
“There are more than 170,000 cases of syphilis [in the U.S.] Last year, cases have doubled in each of the past five years,” Klausner said.
Repeated studies with slightly different designs also found that people who took doxycycline daily or after sex had lower rates of STIs. This approach, known as pre-exposure doxycycline prophylaxis, now has its own name: doxyPEP.
San Francisco Department of Public Health in October Recommended doxyPEP For cisgender men and transgender women who have had a bacterial STI in the past year and who have had condomless oral or anal sex with one or more cisgender men or transgender women in the past year.
For those who meet the second criterion but have not been diagnosed with an STI in the last year, the department recommends a “shared decision-making approach,” in which doctors discuss the benefits and risks of doxyPEP and prescribe it for patients who do not feel well They will benefit, explained Stephanie Cohen, MD, acting director of disease prevention and control in the department’s Division of Population Health.
The department also recommends doxyPEP to anyone diagnosed with syphilis, regardless of gender or sexual partner.
The U.S. has one of the highest rates of STIs in the world, Cohen said, “and San Francisco, in particular, has one of the highest STI rates in the country.”
most A recent study doxyPEP followed 501 men and transgender women in Seattle and San Francisco. About two-thirds were receiving HIV pre-exposure prophylaxis (HIV PrEP), and the remainder were HIV-infected.The results of the study in International AIDS Society (IAS) Conference Earlier this year, it was found that rates of STIs were lower among people who were told to take a single dose of doxycycline within 72 hours of unprotected sex. STI reduction was 66% in the HIV PrEP group and 62% in the HIV-positive group.
“When you’re talking about giving antibiotics before someone has an infection, it’s maybe a bit of a paradigm shift,” said Annie Luetkemeyer, MD, an infectious disease physician and STI researcher at UCSF, who co-led the study.
When HIV PreP came out, there were objections that it would lead to more risky sex or increase HIV drug resistance, she recalls. In fact, “we’ve learned that for some populations, access to HIV PrEP is absolutely necessary to reduce the risk of HIV infection.”
Now, the objection to doxyPEP is that it could lead to more antimicrobial resistance. But Luetkemeyer noted that the high-risk population targeted by the intervention is already exposed to high rates of antibiotic use, primarily to treat sexually transmitted infections.
In the control group of the study, the incidence of STIs within 3 months was 32%, compared with 11% in the doxyPEP group. But doxyPEP use isn’t perfect, with those in the study reporting they took it after an average of 87 percent of unprotected sexual exposure.
“It’s not a question of taking doxycycline versus not taking antibiotics,” Luetkemeyer said. In fact, the control group was 50 percent more likely to be exposed to ceftriaxone, a broad-spectrum antibiotic that is more likely to cause drug-resistant gonorrhea than doxycycline.
However, Luetkemeyer and Klausner say it is important to monitor drug-resistant STIs, as well as other infections such as doxycycline resistance Staphylococcus aureusto ensure that doxyPEP does not increase them.
make things worse?
Luetkemeyer and her colleagues are now investigating whether doxyPEP increases drug-resistant bacteria in people who take it. There are no red flags yet, but research is ongoing.
While San Francisco’s Department of Public Health officially recognized doxyPEP for the first time, doctors who work with high-risk populations have been prescribing it for years. When he treats HIV-infected or at-risk patients, Klausner said, he prescribes prophylactic doxycycline daily or after sex without a condom, depending on the patient’s frequency of sexual activity. For on-demand use, he typically starts at 200 mg for 15 doses and then tops up.
He also noted that there is no set population group that needs doxyPEP, for example, people might benefit from monogamous or relatively monogamous relationships for periods of time between relationships.
“People’s risk profiles are dynamic. … doxyPEP is not a strategy that we encourage people to adopt forever,” he said.
While doxyPEP may increase the risk of drug-resistant infections, it could theoretically also reduce the risk of drug-resistant infections by reducing the burden of sexually transmitted infections and the need for antibiotic treatment in the population, Klausner said.
“It’s been known since the 1970s that sexually transmitted infections — like chlamydia, gonorrhea, syphilis — are perpetuated by a core group,” he said, typically men who have sex with many male partners over the course of a month . “If you can control the spread of infection in a core group, everyone else is more protected.”
Cohen of the San Francisco Department of Public Health said that while “it’s definitely a priority as we roll it out for surveillance to see if there are any worrisome signs of antimicrobial resistance,” for now, “the community wants to Having new tools to protect yourself from STIs outweighs the potential and unknown risks of antimicrobial resistance.”
To be sure, decades of experience have shown that the only other prevention tool — the condom — is not widely adopted by everyone, either because of partner or personal preference.
“For some populations, rates of sexually transmitted infections are really skyrocketing, and what we’re currently offering doesn’t work, so we really need new tools,” Luetkemeyer said.