A push to make use of antibiotics to stop sexually transmitted infections is elevating issues

Gonorrhea micro organism (pictured) are proof against some antibiotics. Credit score: SPL

The well being division in america has change into one of many first to suggest that individuals at excessive threat of contracting a sexually transmitted an infection (STI) take a protecting dose of antibiotics after unprotected intercourse. Scientific trials have proven that the technique can cut back infections resembling chlamydia, syphilis and gonorrhoea. However some researchers fear that it’ll contribute to antibiotic resistance.

Final month, the San Francisco Division of Public Well being advisable that individuals at excessive threat of an infection take a dose of the antibiotic doxycycline after unprotected intercourse to stop bacterial STIs.

Charges of bacterial STIs have been climbing steadily over the previous decade, notably in males who’ve intercourse with males (MSM). “We do not have a instrument to cut back the quantity of it [bacterial] STIs, however solely require folks to make use of condoms,” together with oral intercourse, says infectious illness doctor Jean-Michel Molina on the College of Paris.

Molina led the primary take a look at1 of doxycycline post-exposure prophylaxis—a preventative remedy technique referred to as doxyPEP—reported leads to 2018. In that trial, 22% of these utilizing doxyPEP, and 44% not, had contaminated with an STI over 9 months. Antibiotic use resulted in a 70% discount in chlamydia infections and a 73% discount in syphilis infections in individuals. Gonorrhea infections weren’t considerably decreased.

DoxyPEP is just like the extremely profitable technique of giving antivirals earlier than unprotected intercourse to stop infections from HIV – often called HIV-PrEP. Taking HIV-PrEP reduces the danger of sexually buying HIV by round 99%.

Check success

San Francisco adopted the coverage after interim outcomes from one other trial – referred to as DoxyPEP – have been offered on the Worldwide AIDS Convention in Montreal on the finish of July. That trial, during which MSM and transgender ladies have been both residing with HIV or taking HIV-PrEP, was stopped early as a result of taking doxycycline after unprotected intercourse was much less efficient in to cut back STIs. doxyPEP was provided to everybody enrolled within the trial, led by infectious illness doctor Annie Luetkemeyer on the College of California, San Francisco, doxyPEP. Chlamydia and syphilis infections have been greater than 70% decrease, and gonorrhea infections have been 55% decrease in every three-month interval in those that took doxyPEP. In individuals who didn’t take doxyPrep, about 30% have been contaminated with a number of STIs every season.

Syphilis in males may cause critical well being issues, resembling blindness and nerve injury if left untreated. Chlamydia and gonorrhea infections are uncommon in males, however in ladies, they will result in infertility. And syphilis can move to unborn youngsters and trigger miscarriage, nonetheless start, or mind and organ injury in infants born with the illness.

However researchers are divided on whether or not the proof of effectiveness in MSM alone is sufficient to formally endorse doxyPEP. Manik Kohli, a sexual well being doctor and researcher at College Faculty London, says that extra knowledge from a number of trials are wanted to point out whether or not doxyPEP results in antibiotic resistance.

Different jurisdictions are taking a extra cautious method than the San Francisco Division of Public Well being, which didn’t reply Naturerequest for remark. The UK Well being Safety Company and the British Affiliation for Sexual Well being and HIV say they don’t help the doxyPEP technique for stopping syphilis or chlamydia, partly due to an absence of information on antimicrobial resistance.


When uncovered to antibiotics, micro organism that harbor resistance and survive can unfold. Chris Kenyon, a microbiologist on the Institute of Tropical Drugs in Antwerp, Belgium, says that utilizing doxycycline to stop infections drastically will increase an individual’s publicity to the antibiotic, which might trigger in opposition to. Within the DoxyPEP trial, some individuals took greater than 20 doses of doxycycline monthly, an quantity Kenyon describes as “astronomical.”

Doxycycline is an “essential” antibiotic for treating different circumstances, together with pores and skin infections attributable to Staphylococcus aureus and bacterial pneumonia, says Kenyon. DoxyPEP might result in the emergence of antibiotic resistance within the micro organism that trigger these ailments and restrict remedy choices, he says.

He says well being care employees ought to take a cautious method when prescribing antibiotics as preventive remedy, particularly amongst MSM. They’re a primary inhabitants for the emergence of antibiotic resistance if antibiotic use is excessive, as individuals are prone to have polygamous intercourse companions and networks that improve the prospect of micro organism being unfold face. Intercourse employees are one other group during which antimicrobial resistance has emerged previously.

Resistance to tetracycline class antibiotics, which incorporates doxycycline, is already widespread for gonorrhoea. In america, about 25% of gonorrhea instances are attributable to tetracycline-resistant micro organism. Elsewhere, resistance charges are larger, with research reporting charges nearer to 60% or 70% in Europe1,3.

Molina expects that doxyPEP’s effectiveness in opposition to gonorrhea will rely on resistance ranges in the area people and should lower over time as resistance ranges rise.

However Luetkemeyer says early outcomes from a second French trial, referred to as DOXYVAC, present that doxycycline reduces gonorrhea infections – regardless of excessive resistance charges. The outcomes recommend that the drug nonetheless prevents an infection from taking maintain, even when it’s not efficient in treating a longtime an infection. “It typically takes so much much less drug to stop illness than it does to treatment illness,” she says.

Different ailments

Resistance to doxycycline has not emerged in chlamydia or syphilis. Understanding whether or not doxyPEP results in resistance in these ailments might take years, says Molina.

Luetkemeyer and her colleagues have collected swab and stool samples to see if folks utilizing doxycycline as a preventative change the group of microorganisms that reside within the intestine or improve it. antibiotic resistance. These outcomes can be offered at a convention in February 2023. Luetkemeyer additionally notes that there are different sources of doxycycline locally that will contribute to resistance.

One hope is that the usage of doxyPEP in MSM might cut back the degrees of STI micro organism within the wider group – together with ladies, who’re most affected by chlamydia and gonorrhea infections – simply as HIV-PrEP has performed for HIV in high-income nations.

However Kenyon doubts that doxyPEP will cut back STI charges, which might stay very excessive even after main interventions. Within the late Nineties, a large-scale remedy marketing campaign with the antibiotic azithromycin to eradicate an outbreak of syphilis in Vancouver initially decreased charges, however quickly rebounded2.

Off-label use

Since Molina and her colleagues revealed the outcomes of the primary doxyPEP research in 2018, folks have been utilizing doxycycline off-label as a preventative measure, he says. Kenyon fears that doxyPEP might expose folks to the antibiotic for years and even a long time.

For people who find themselves already utilizing doxyPEP, public well being suggestions are unlikely to make them cease, says Kohli. Following Luetkemeyer’s presentation on the Worldwide AIDS Convention in July, the US Facilities for Illness Management and Prevention launched data to information the usage of doxyPEP. The company will challenge steerage after the ultimate knowledge is launched and reviewed, a spokeswoman mentioned Nature.

Tips to be used are essential to tell folks concerning the security of a technique they could already be utilizing, and to offer preventive remedy for individuals who could not have the ability to apply for doxyPEP on their very own. , says sexual well being doctor Jenell Stewart at Hennepin Well being Care in Minneapolis, Minnesota. Stewart is main a trial of doxycycline prophylaxis in Kenya for girls taking HIV-PrEP4.

Regardless of the unknown, Stewart says the advantages outweigh the dangers. “Folks ought to have entry to this instrument, if it is sensible for them and their way of life,” she says.

About the author


Leave a Comment