Antibiotic taken after sex significantly reduces STDs – study
WASHINGTON, USA — An antibiotic taken after sex without a condom can significantly reduce rates of three bacterial STDs among high-risk groups, clinical study data revealed Wednesday.
The research was presented at the 24th International AIDS Conference in Montreal, where it was hailed as a major development.
“It has the ability to change the guidelines” on clinical practice, Steven Deeks, an HIV expert at the University of California, San Francisco (UCSF), who was not involved in the study, told AFP. study.
Doxycycline reduced rates of gonorrhea and chlamydia by more than 60% in men who have sex with men (MSM) and also appeared to be very effective against syphilis, but there were not enough cases to reach statistical significance.
The trial was halted early because researchers found the drug undeniably worked and it would have been unethical to continue testing.
The study comes amid rising rates of these diseases, particularly among MSM, whose use of condoms has declined since the advent of effective pre-exposure prophylaxis (PrEP) pills against HIV.
A previous trial conducted by French researchers, which used doxycycline as post-exposure prophylaxis (PEP), had shown that it was effective against syphilis and chlamydia in MSM, but not against gonorrhea.
For the new study, the researchers recruited about 500 people, mostly MSM, but also transgender women and people of diverse gender, at sites in San Francisco and Seattle.
Some were taking PrEP for HIV, while others were living with HIV.
In both groups, about two-thirds received doxycycline, while one-third did not. They were followed to monitor their results every three months.
The pill, dosed at 200 milligrams, was administered within three days of exposure. Participants could continue taking it as needed based on the amount of sexual contact they had.
The intervention reduced the incidence of STDs by 62% in the group living with HIV and by 66% in the group taking HIV PrEP.
Side effects were mild and compliance levels remained high.
“We now have two studies that support the use of doxycycline as a PEP in men who have sex with men,” study leader Annie Luetkemeyer of UCSF told reporters at the conference on the AIDS.
“I really think we’re at a stage where we need to think very seriously about rolling this out and how to incorporate it into the guidelines.”
She pointed out, however, that currently the data supports treatment as a targeted intervention among high-risk groups who have a high prevalence of STDs — not everyone.
Further studies are also needed to better understand potential impacts on antibiotic resistance, the authors said.
Researchers want to know if it could increase the resistance of STDs – which is thought to be more possible for gonorrhea than chlamydia and syphilis – so-called “bystander” bacteria that live on the body and in the throat.
They also want to probe the potentially disruptive impact on the gut microbiome.