Taking antibiotics after sex reduces risk of STIs

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According to a study presented to 24th International AIDS Conference to Montreal.

“The use of doxycycline after condomless sex has the potential to be an effective strategy to significantly reduce sexually transmitted infections in targeted populations with high rates of STIs,” the researcher from the l. study by Annie Luetkemeyer, MD, of the University of California, San Francisco.

“It’s not for everyone,” she told an AIDS 2022 press conference. “But there are populations that are really suffering from the STI epidemic, and there It’s time to act on the data and really think about incorporating it into the guidelines and deploying it in a safe and thoughtful way.”

Preparation greatly reduced the likelihood of contracting HIV, but going without condoms puts people at risk of other sexually transmitted infections (STIs). The guidelines recommend that people using PrEP should be screened for bacterial STIs every three months, which allows for prompt treatment, but it would be best to prevent them in the first place. Previously, the French IPERGAY trial, which evaluated on-demand PrEP, provided preliminary evidence that post-exposure prophylaxis (PEP) with doxycycline reduced the incidence of STIs.

“These are the kinds of innovations that clinicians, patients and communities desperately need to fight the epidemic of STIs in the United States,” said David Harvey, executive director of the National Coalition of STD Directors ( NCSD), said in a press release. “Our conclusion to draw from the DoxyPEP study is that we are headed for a future where symptomatic infection and community spread may be entirely unnecessary for some of our most at-risk neighbors and patients.”

The DoxyPEP trial recruited more than 500 transgender men and women who have sex with men from public health clinics in San Francisco and Seattle. Of these, 4% identified as trans or “gender diverse” women. About a third (174) were living with HIV and 327 were taking PrEP. The median age was 38, 67% were white, 30% were Latino, 11% were Asian/Pacific Islander, and 8% were black.

The study population was at high risk for recurrent STIs. They had been diagnosed with an STI in the past year (69% gonorrhea, 58% chlamydia, 20% syphilis), they reported a median of nine sexual partners over the past three months, and about 60 % said they had recently used the substance.

Participants were randomly assigned in a 2:1 ratio to receive a single dose of 200 milligrams of doxycycline PEP by mouth within 72 hours of condomless sex (not to exceed one dose per 24 hour period) or the standard of care, which is regular testing and treatment after diagnosis. They were tested for gonorrhea, chlamydia and syphilis every three months.

The study was supposed to last until May 2023, but it was stopped a year ago after an interim analysis showed that doxycycline PEP significantly reduced the incidence of STIs.

Among participants living with HIV, doxycycline PEP reduced the odds of being diagnosed with a bacterial STI per trimester by 62% compared to standard of care (incidence 11.8% vs 30.5%, respectively). With regard to specific STIs, the incidence of gonorrhea decreased from 20.3% to 8.9% (a reduction of 57%), chlamydia decreased from 14.8% to 3.9% (a reduction of 74%) and syphilis fell from 2.3% to 0.7% (a reduction of 77%). % reduction).

The risk reduction was even greater for HIV-negative participants on PrEP. In this group, there was a 66% reduction in new STIs per trimester compared to the standard care group (10.7% versus 31.9%). Gonorrhea decreased from 20.2% to 9.1% (55% reduction), Chlamydia decreased from 12.1% to 1.4% (88% reduction), and Syphilis decreased from 2.7 % to 0.4% (87% reduction).

In both groups, doxycycline PEP was safe and well tolerated, and compliance was high. Participants reported a median of about seven sex acts per month, 87% of which were covered by doxycycline. More than half (54%) reported taking less than 10 doses per month, 30% took 10-20 doses, and 16% took more than 20 doses.

Most participants (88%) said using doxycycline after sex was acceptable, and only 1.5% stopped due to intolerance or personal preference. No serious adverse events or serious laboratory abnormalities were reported.

Doxycycline PEP Concerns

A major concern with doxycycline PEP is that overuse of antibiotics can lead to drug resistance. Gonorrhea is already resistant to most drugs previously used to treat it. Among the subset of gonorrhea specimens tested in this study, approximately 20% showed resistance to tetracycline (a related drug) at baseline, similar to the level of the US population, but this increased over time in the PEP group to doxycycline.

Doxycycline is not usually used to treat gonorrhea, chlamydia, or syphilis, which means people who develop resistance have other treatment options. Also, a lower daily dose of doxycycline is used for weeks or months to prevent malaria in travelers, and this has not promoted resistance.

Another potential concern is whether frequent antibiotic use will disrupt the microbiome, the ecosystem of healthy bacteria that normally live in the gut, vagina, and elsewhere in the body. Resistance and microbiome analyzes are in progress.

However, Leutkemeyer noted, people in the control group contracted STIs so often that they spent a significant portion of their time on doxycycline treatment anyway. Using doxycycline as PEP instead of treatment prevents symptoms, reduces suffering, and decreases the length of time people can transmit STIs. In fact, some people took doxycycline often enough — almost every day, if they had frequent sex — that it probably worked like PrEP for STIs, she said.

Equitable access to doxycycline PEP could be an issue. Some homosexuals were already using it before its approval for this indication, but proponents wonder if it will reach everyone who needs it. A decade after its approval, black and Latino men who have sex with men and cisgender women are still not using PrEP as much as white gay men, and the disparity is growing. Inexpensive generic versions of doxycycline are widely available, but the cost could add up if people take it frequently.

Cisgender women and transgender men may also benefit from doxycycline PEP, but this has not yet been studied in these groups. DoxyPEP investigator Connie Celum, MD, MPH, of the University of Washington, said a study of cisgender women in Kenya is underway and should have results next year.

The NCSD is working to update STI programs on the results of DoxyPEP and plans to advise the Centers for Disease Control and Prevention (CDC) on the implications in the field.

“We urge the CDC to immediately put this research into the hands of clinicians and update treatment guidelines so patients don’t have to wait for best-in-class care,” Harvey said.

In a statement responding to the results of the studythe CDC said it was “encouraged” by the early data.

“Further review of the data presented, and possibly additional analyses, will be needed to develop clinical guidance on the safe and effective use of this bacterial STI prevention strategy in gay and bisexual men and transgender women. It will be essential to provide guidance that will maximize the effectiveness of STI prevention, while minimizing individual and potential public health risks,” the agency said. “We must act quickly to implement powerful prevention strategies And it is our public health imperative to develop responsible guidance based on careful consideration of all available data and public health risks and benefits – we cannot cut corners when it comes to STIs. is about people’s health.

Doxycycline PEP adds a new tool to the toolbox for safer sex, but, as has happened with HIV prevention pills, some fear it will encourage people to have more sex without condom.

“When PrEP came out, we saw a lot of shame and stigma – why not just use a condom? – but we need more tools. Hopefully it doesn’t come with the shame and blame that has accompanied the first cycle of PrEP,” said Leutkemeyer.

“The [DoxyPEP] the data confirms the harm reduction practices that many of us on PrEP have already adapted,” Damon Jacobs, a longtime advocate who started the PrEP Facts Facebook Group, POZ says. “We have the right and ability to enjoy sexual pleasure and minimize risk at the same time.”

Click here to read the study summary.
Click here for more reports on AIDS 2022.
Click here for more information on PrEP.


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