CDC recommends using antibiotic as a ‘morning after pill’ for STDs

Doctors are being told to consider prescribing a ‘morning after pill’ after sex to tackle the nationwide explosion of STD infections.

The CDC released new guidance today that recommends the antibiotic doxycycline be prescribed within 72 hours of unprotected oral, vaginal or anal sex with a new or recurring partner.

Studies suggest the drug could prevent up to 70 percent of chlamydia and syphilis infections and up to 50 percent of gonorrhea cases.

It works by killing bacteria before they become so advanced they cause symptoms and can be transmitted to others.

It comes amid an ‘STD epidemic’ in the US, with nearly 700,000 more Americans now catching chlamydia, gonorrhea or syphilis every year compared to before the Covid pandemic.

The new recommendations apply to gay and bisexual men and transgender women with a history of at least one STI.

But it may also be available to heterosexual men and women should they go to doctors fearing they have been exposed to an STI.

The guidance, published today, reads that for these groups ‘providers should use their clinical judgement and shared decision-making to inform use’.

Patients who receive the course will also need to be tested for an STI when they begin and at three and six months after taking the drug.

Doxycycline for STIs is prescribed as a 200 milligram (mg) dose to be taken twice a day for seven days.

It is only meant to lower STI risk, while the traditional morning-after pill, Plan B, should still be taken within 72 hours of unprotected sex to prevent an unwanted pregnancy. 

Officials said they were recommending the course — dubbed doxycycline post-exposure prophylaxis (Doxy-PEP) — for gay and bisexual men because this group is disproportionately affected by STIs.

The group has higher rates of syphilis than the general population, and still makes up more than half of all new HIV infections.  

Officials said: ‘Doxy PEP represents the first new STI prevention tool in decades, at a time when innovation in the nation’s fight against STIs is desperately needed. 

‘These guidelines will be updated as additional data become available.’

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Doxycycline has been in use in the US since it was approved in 1967, and is taken in 60-day courses of two pills per day.

It is available on prescription, with about 9million written every year to treat everything from a chest and dental problem to a skin infection like rosacea and STIs.

It is not always prescribed for bacterial STIs, with the CDC recommending azithromycin for chlamydia, ceftriaxone for gonorrhea and penicillin for syphilis.

The infections are already becoming resistant to these drugs, with concerns raised last year over two cases of super-gonorrhea — or gonorrhea resistant to antibiotics — detected in Boston, Massachusetts.

But there are concerns that prescribing doxycycline to treat the infections could have the same effect.

Studies suggest around five percent of chlamydia infections may already be resistant to doxycycline, with resistance likely already present in gonorrhea and syphilis.

Studies suggest there was no marked increase in resistance when doxy-PEP was used, but there was an uptick in resistance levels among Staph bacteria — which can cause throat infections — rising from five to 13 percent. 

Doxycycline is also associated with side effects including vomiting or diarrhea, headaches and a feeling of nausea.

It comes amid an explosion of STIs in the US, with every state seeing cases of syphilis and gonorrhea spike between 2017 and 2022, the latest data available.

Only chlamydia, the most common STI in the US, appeared to be triggering fewer infections — but it is feared that this is because fewer tests were being done.

Scientists fear the surge in STIs is being driven by riskier sexual behaviors nd a reduction in condom use.

Experts are particularly concerned about rising syphilis rates because the disease can cause birth defects in developing fetuses. 

The latest guidance was based on three studies on gay and bisexual men who received 200 milligrams (mg) of doxycycline within 72 hours after sex.

This included a 2022 trial carried out in San Francisco and Seattle, where 501 gay and bisexual men and transgender women who hadn’t previously used a condom during sex were given doxycycline up to 72 hours after sex.

And a 2022 trial carried out in France involving 332 people who received doxycycline within 72 hours after sex, with a history of condomless sex.

Participants were followed for 96 weeks, with results showing a 50 percent reduction in the risk of a gonorrhea infection and an up to 90 percent reduction in risk of a chlamydia or gonorrhea infection.

The recommendation follows a public consultation on the measure, which was first revealed in April last year .