The United States is poised to develop a powerful new weapon in its long battle against sexually transmitted infections: a decades-old antibiotic repurposed as a preventative pill.
DoxyPEP, or doxycycline used as post-exposure prophylaxis, has been shown to significantly reduce the risk of chlamydia, gonorrhea, and syphilis when used after unprotected sex.
The Centers for Disease Control and Prevention (CDC), which is developing national guidelines for physicians, must weigh the need to contain record high rates of STIs affecting millions of Americans against the emergence of more antibiotic-resistant strains.
“Innovation and creativity are critical in public health, and more tools are desperately needed,” senior CDC official Jonathan Mermin told AFP.
But the recommendations, set to be released this summer, will remain narrow in scope.
They are likely to target only the most vulnerable groups in gay men and transgender women with a history of prior infection.
As word spreads, some clinics are already prescribing doxypep.
Malik, a 37-year-old man from Washington, said his doctor recently told him he could start using doxycycline as a “morning-after pill” after risky sex, which he had to do twice — even after a partner didn’t warn him. The condom was removed.
Two-thirds reduction
After nearly a decade of growth, the number of reported cases of bacterial infections in the U.S. will rise to 2.5 million in 2021.
There are several issues behind this increase: Fewer people are using condoms since the advent of PrEP – the daily pill that significantly reduces the chance of HIV infection.
And those on PrEP are recommended to be screened every three months, possibly increasing the detection of infections.
Then there is the basic epidemiological fact that the greater the number of infected people, the more likely they are to become infected.
Researchers found doxyPEP effective in three out of four trials.
“What we found was about a two-thirds drop in sexually transmitted infections every three months,” said Annie Luetkemeyer, who Led with a US trialAFP said.
Physician-scientists at the University of California, San Francisco recruited nearly 500 men in San Francisco and Seattle among men who have sex with men and transgender women.
Effectiveness was greatest for chlamydia and syphilis, both of which were reduced by about 80 percent, while for gonorrhea it was about 55 percent. There were some side effects.
Antibiotic resistance
Expanding access to doxycycline has fueled concerns about antibiotic resistance, particularly in gonorrhea, which is changing rapidly.
But preliminary research hasn’t shown cause for alarm.
Connie Selam of the University of Washington, who co-led the US study, told AFP researchers examined gonorrhea samples from breakthrough infections in the doxypep group and compared them to a group that did not take the pill.
Although they found a slightly higher rate of resistant gonorrhea in the doxypep group, he says the finding means the pill is less effective against strains that are already resistant rather than causing resistance.
DoxyPEP may even enhance responsible antibiotic stewardship – reducing the incidence of infections, thus reducing the need for antibiotic treatment.
If it cuts gonorrhea cases by about 50 percent, it could reduce the number of people who need antibiotic treatment with the current frontline treatment drug ceftriaxone, which doctors are keen to save.
Long-term studies are needed, both on the effect on STIs but on “bystander” bacteria such as Staphylococcus aureuswhich live inside the human nose but sometimes cause serious infections
‘Additional Tools’
Malik says that while he’s glad he can use doxypep as a last resort, he wishes more men were willing to use condoms. Since moving to America from South Asia, she has received relatively little interest on the dating app Grindr when she says she is unwilling to have condomless sex.
But Stephen Abbott — a doctor at the Whitman-Walker Clinic in Washington who prescribes and uses doxyPEP — says it’s crucial to meet people where they are.
“From talking to patients, and being part of communities that are now on PrEP… I think the age of prevention through condoms is fading,” he told AFP.
A 42-year-old man in London who runs a cultural organization told AFP that word about doxypep had spread through the international gay party circuit and that he supplied it on the black market and through partners who bought large quantities in Mexico.
It basically worked for him, even though he had a breakthrough infection of throat gonorrhea. He said he looks forward to the United Kingdom adopting similar guidelines so people have the right information and aren’t left to guess about the right dosage.
For Luetkemeyer, doxypep will not be “the answer” to the STI epidemic, and there is considerable interest in developing a gonorrhea vaccine.
“But I’m optimistic… I think it’s an additional tool,” she said.
© Agence France-Presse