The statistics speak for themselves for Doxy-PEP. A single dose of the antibiotic doxycycline taken after unprotected sex halved the incidence of early-onset syphilis and chlamydia among gay and bisexual men and transgender women in San Francisco, researchers said Monday. City health officials said at a conference on retroviruses and opportunistic infections. (CROI) in Denver.
These results bring hope because in recent years, the United States has experienced a significant increase in sexually transmitted infection (STI) cases across the country.
“The morning after the STI shot”
This preventive strategy, called doxy-PEP, was the subject of a targeted prevention campaign launched in October 2022 by the City of San Francisco’s public health services. In this setting, gay and bisexual men and transgender women with a history of STIs or with multiple sexual partners were given doxycycline, a frequently used broad-spectrum antibiotic.
How does this treatment work? Doxy-PEP, short for “doxycycline post-exposure prophylaxis,” means that the antibiotic doxycycline is taken after unprotected sex, specifically to prevent STIs. It’s kind of like the morning-after pill, but for STIs, New York City Health Services explained, which closely monitored the results of this experiment. “Unprotected sex is oral, anal or vaginal sex during which a condom is not used for the entire duration of intercourse.”
Participants were thus instructed to take two 100-milligram tablets of doxycycline within 24 to 72 hours after unprotected sex. And within a year, new cases of chlamydia and early syphilis dropped by half.
which contains STIs
“It’s not subtle, it’s very rapid and we’re seeing the beginning, not the end,” said San Francisco Public Health Medical Director Dr. Hyman Scott said in an interview. This is what we want for the prevention of STIs.”
And in practice, “in the public health sector it is often not the case that there is consistency between population-level surveillance data, clinical service observations and clinical trial results, and at the same time,” added Professor Landon Myer, President of CROI 2024. and the University of Cape Town, during a press briefing.
Dr. Dermatologist-Venereologist responsible for the Hôtel-Dieu Sexual Health Center (AP-HP). For Nicolas Dupin, “Wearing a condom is the most effective way to protect yourself from STIs. But doxy-PEP is one of the chemical approaches to STI prevention. A portion of the population at risk does not use condoms regularly.
In addition, many of these STIs can be contracted through orogenital contamination: sexual intercourse that carries a low risk of HIV transmission, and is therefore even less safe in this population. Which makes Doxy-PEP an interesting prevention tool.
And in the Atlantic, as in the rest of the world, there is an urgent need to halt the spread of STIs. In the United States, syphilis, which was virtually eradicated in the past, has reached its highest rate of new infections reported since the 1950s, the Centers for Disease Control and Prevention (CDC) said in January. “Syphilis is a highly contagious STI, caused by the bacteria, Treponema pallia, that primarily affects men who have sex with men (MSM),” Health Insurance suggests. Although it can be treated very well in the early stages with antibiotic treatment, in the absence of treatment, syphilis can “affect the brain, eyes, heart” in advanced stages, and cause “dementia, blindness, deafness” or even “death”. , warns the World Health Organization (WHO).
“We lack perspective on the dangers of antibiotic resistance”
Doxycycline has the advantage of being known, as this antibiotic has been used for years to fight many infections, from urinary tract infections to acne. On the other hand, “Doxy-PEP is a new way of using this antibiotic, so we don’t know if it has long-term effects,” emphasizes the New York Public Health Services. And “we don’t yet know whether taking Doxy-PEP will affect the “good” bacteria in the gut, or whether other bacteria that cause STIs or other infections will become resistant (to this antibiotic), so treatment is more complicated. ,” identify. Health officials in the city of San Francisco.
So when is Doxy-PEP in France? “I don’t think the recommendations of the health authorities are going in this direction for the moment, because the risk of the emergence of antibiotic resistance is still unknown,” said Dr. Dupin believes. This is the whole problem that this treatment creates, already in France there has been a significant increase in the resistance of gonorrhea to cyclins (this class of broad-spectrum antibiotics). This also raises the question of the long-term risks of potentially seeing the emergence of resistance in syphilis, chlamydia, or other microbes to this family of antibiotics. However, to date, there is a lack of perspective on the potential risks of antibiotic resistance.
On the other hand, he continues, “In the field, I see my best-informed patients who are taking doxy-PEP independently, outside of medical advice and recommendations.”
No or little effect of vaccination
Among other avenues for prevention of this STI: vaccination and post-contamination treatment, explored as part of the DOXYVAC trial, of which Dr Dupin is a co-author. “The final results of the trial demonstrate the post-exposure efficacy of doxycycline in reducing the incidence of chlamydial infection, syphilis and, to a lesser extent, gonococcal infection,” the authors state, confirming the findings. Real life observations in San Francisco. “On the other hand, they do not allow us to conclude on the effectiveness of the meningococcal B vaccine on the risk of gonococcal infection.” This vaccination has “only a marginal effect, it is disappointing”, Dr Dupin believes.
But scientific research is ongoing. As part of the “SY-DOXY” trial, led by AP-HP and coordinated by Dr Dupin, “we will include 200 participants from around twenty sexual health centers in mainland France, but also from Martinique and Réunion, to demonstrate that we use doxycycline not only to prevent No, but we can also treat syphilis in the early stages.
