According to a recent clinical trial at the University of Washington, a new study has found that antibiotics that have been given for decades can help prevent sexually transmitted bacterial infections.
In the study, UW researchers, in collaboration with infectious disease specialists at the University of California, San Francisco, found new strategies to reduce the prevalence of bacterial sexually transmitted infections – gonorrhea, chlamydia and syphilis – that are on the rise in the United States. For more than five years around the world, Dr. Connie Selum, a UW professor of global health, medicine and epidemiology, led the study.
As the test ended early and the analysis continued, the results have not yet been published and the researchers declined to share specific data.
The results have been strong, Selum said. For about a year and a half, she and other researchers found evidence that a dose of doxycycline helped prevent bacterial STIs in men who had sex with men and transgender women with gonorrhea, chlamydia, or syphilis. he said.
“We need new tools to stop the spread of STIs,” Selum said. “Although not life-threatening, they can cause serious illness in both men and women. … This is one of the first new interventions that can be used. “
Bacterial STIs in King County have been rising steadily for years, the doctor said. Julie Dombrowski, co-researcher of the study, also helps run the Public Health – HIV / STIs program in Seattle and King County. According to the county’s annual report, syphilis, gonorrhea and chlamydia rates among men who had sex with men in 2019 were the highest since the data were released in 1992.
The level of bacterial STIs has shown “massive growth” among the general population, Dombrowski said.
The clinical trial initially recruited about 550 STIs from public health clinics in San Francisco and Seattle last year. Those taking doxycycline – a widely available but rarely used antibiotic used to treat some bacterial infections – took 200 milligrams within 72 hours of unprotected sex, Selum said. Those in the “control unit” of the study did not receive antibiotics.
Before starting the test, researchers needed to determine how strong the data needed to stop the study early, he said.
Last month, the Independent Data Security Oversight Board reviewed the results twice a year, and the researchers came to a “clear conclusion.” Participants who took doxycycline had fewer infections than those who were HIV-positive or received HIV PrEP (prophylaxis), Selum said.
“If you have gonorrhea, chlamydia or syphilis, or if you have antibiotics in your body soon, you won’t get an infection,” he said.
He said the antibiotic, which still required a prescription, was generally safe and well tolerated.
Despite preliminary results, more work is needed to understand the effectiveness of the drug in different populations and whether doxycycline can withstand the microbes that develop when bacteria change over time and do not respond to the drug, Selum said.
“One of the next steps will be to really review the data for groups like the CDC and policy groups,” he said. In addition, several other relevant studies are underway, including in Kenya – led by UW investigators in Canada, Australia and France.
Adding doxycycline as a tool to prevent infection is a promising first step in reducing STIs, and Selum said more diagnostic tests and screenings are needed.
“We hope that now there is a growing effort to avoid syndromic management, which should be symptomatic before treating STIs,” he said. “And 90% of men and women with chlamydia and gonorrhea have no symptoms.”
Selum and his team will present their findings at an international AIDS conference in Montreal in late July as they continue to monitor participants this summer.
“In many parts of the world, there is a lack of evidence, so it’s important that we have interventions,” Selum said. “… The development of new vaccines will take a long time, so over time it could be a way to reduce the burden of STIs.”