We are closer to the morning-after pill for sexually transmitted diseases.

A promising new single-dose antibiotic therapy dramatically reduces the risk of transmission of chlamydia, gonorrhoea and syphilis except for viruses like the HPV tests show. Medicine could be close to achieving a long-awaited goal: a “morning after pill” to prevent sexually transmitted diseases (STDs). The pill, a 200-milligram tablet of the antibiotic doxycycline, has been studied for a decade. Results from a study published in the New England Journal of HPV Medicine Tests indicate promising prospects.

In the HPV study conducted between San Francisco and Seattle, participants who took one dose of the drug within 72 hours of unprotected sex had a significantly lower likelihood of contracting chlamydia, gonorrhoea, or syphilis compared to those who did not take the pill.

Balancing Benefits and Risks

As always in medicine, the results are accompanied by side notes and the benefits are offset by some risks.

Study Participant Demographics

The study focused solely on gay and bisexual men, along with transgender women and non-binary individuals assigned male sex at birth. Researchers limited the study to those tested with a sexually transmitted disease within the past year, including HPV. Cisgender women were excluded due to the antibiotic’s less effective performance in previous studies involving them.

Potential Risks

It was also reported from tests, that without further investigation, the possibility that chronic antibiotic administration could induce resistance among the bacteria causing STIs or others in the participants’ bodies.

Promising Results Amid Uncertainty

Promising results have generated genuine enthusiasm among doctors and potential recipients of doxyPep. It is currently known as doxycycline post-exposure prophylaxis. However, health authorities like the CDC have not formally approved its use.

“I think this is a real turning point – says Paul Adamson, infectious disease specialist and professor of clinical practice at the University of California in Los Angeles. In the United States, tests for STIs of bacterial origin are widespread. By far the hardest hit are gay and bisexual men who have sex with men, and tools to help them are currently in short supply.”

Understanding the Impact

To understand the impact that doxyPEP could have, the current spread of sexually transmitted diseases must be taken into account. In short, virus infections like HPV are exploding, and so is the demand for test kits.

Starting from 2017, according to CDC data, the most relevant of these diseases have reached historical highs: gonorrhoea has increased by 28 per cent and syphilis by 74 per cent. And suppose it is true that chlamydia diagnoses have not yet returned to pre-Covid levels. In that case, the health authority fears that this is due to the intermittent nature of the health service during the pandemic.

These are all infections that, without tests and treatment, can have serious long-term consequences like HPV. They increase the risk of contracting HIV. In 2021, congenital syphilis caused 220 deaths among fetuses and newborns in the United States. And gonorrhoea is developing resistance to even the latest antibiotics.

Prevention is almost always better in STD Test medicine than cure: vaccines and other prophylactic measures cost less and can be planned. The HPV research from tests aims to develop simple prevention methods for STDs. Similar to the morning-after pill for pregnancies, individuals can take these drugs shortly after unprotected intercourse. They don’t rely on immediate decisions.

The first trial of doxyPep

Two thousand fifteen researchers published a small trial conducted in the United States between 2011 and 2012. They found that among HIV-positive tests in men who took the post-exposure dose, the incidence of sexually transmitted diseases was reduced by three-quarters. Shortly after that, the results attracted attention on social networks. Men in homosexual relationships exchanged information on using doxycycline preventively. In 2017, a large French study analyzed the incidence of sexually transmitted diseases among men taking HIV pre-exposure prophylaxis (PREP). The study found that doxyPEP could reduce syphilis and chlamydia infection rates by nearly 70 per cent.

Recent Studies Confirming Doxycycline Therapy

Last summer and this spring, the two main international HIV conferences hosted presentations that confirmed the therapy’s effectiveness in most cases.

San Francisco and Seattle Study

Many of these presentations were from the San Francisco and Seattle study published in the New England Journal of Medicine. The results were so striking that the authors stopped the trial early, in May 2022.

It had emerged from tests that in 501 men who have HIV or are taking HIV Prep, a single dose of doxycycline taken within 72 hours of Unprotected intercourse reduced the overall incidence of the three main sexually transmitted diseases by approximately two-thirds.

“Our goal was to project everything into a real context,” says Anne Luetkemeyer, a researcher and professor at the University of California, San Francisco. The test study included a heterogeneous sample that involved people on HIV Prep and those affected by it. She adds that these two samples may differ in behaviour and sexual networks.

With the French experiment, continues Luetkemeyer, “We now have two studies that demonstrate in both groups a very similar effectiveness”. And the results of these two studies could be enough to bring doxyPep into mainstream medicine. It has already happened somewhere.

San Francisco’s public healthcare department became the first in the region to approve the use of doxyPep in its territory.

Last October, San Francisco’s public health department approved doxyPep’s use. Doctors on Twitter shared they started prescribing it to patients after the study’s publication. They found the results encouraging.

Whenever a new disease control tool is about to be introduced to the general public in the United States, the CDC must express an opinion. So far, the organization has not issued any official guidelines on using doxyPep. After presenting the preliminary results at the conferences, the CDC issued “notes for the population and healthcare professionals,” aiming to communicate the findings and acknowledge the current use of doxyPep.

Considerations on Doxycycline Prophylaxis

A spokesperson for the organization emailed Wired US that a draft guidance document for doctors could arrive “by this summer.”

Risks and Side Effects

When it arrives, the CDC is expected not to recommend doxyPep for universal use. “It would make sense to make it available to those at high risk [of sexually transmitted diseases] – says Luetkemeyer – a tested group that includes men who have sex with men, who take Prep or are HIV positive, and who have already contracted HPV or other sexual infections. As a champion, he seems adequate to me.” Potential recipients, then, may not want to hire it.

Like almost all antibiotics, doxycycline has side effects: photosensitivity, diarrhoea, and even intense nausea. And it doesn’t work the same way for everyone. In the test study conducted on French men, the antibiotic failed to eradicate gonorrhoea infections, although it was very effective in reducing syphilis and chlamydia.

In the only study so far conducted on cisgender women, carried out in Kenya in 2021, doxycycline prophylaxis (in this case known as dPep) had no effect in suppressing sexually transmitted diseases. That was a disappointment: Women at high risk for STDs need prevention just as much as men.

The results

The HPV results have left researchers perplexed, who are now sifting through the data to understand what may have made the difference: whether the 449 participants failed to take the drug at the correct time, for example, or whether doxycycline acts differently in female organs. Then in male ones. “More than two hundred women came to us to learn about the test results and were amazed and disappointed – declares Jenell Stewart, head of the study, doctor-scientist and assistant at Hennepin HPV Healthcare Center in Minneapolis -. Before saying it doesn’t work for women, we prefer to focus on deciphering the results.”

One factor that may have influenced the studies conducted in Kenya and France is antibiotic resistance. Stewart notes that all gonorrhoea isolates from women infected while taking deep showed strong resistance to tetracycline, the drug family to which doxycycline belongs.

Doxycycline Resistance: A Comparative Analysis

The overall resistance rate of gonorrhoea at the time of the French study was 56 per cent. In the United States, doxycycline isn’t the preferred drug for gonorrhoea, resulting in a 20% resistance rate. This suggests why doxyPep performed better in the US study. However, concerns arise about potential increased drug resistance with widespread use.

The US study failed to answer the question of HPV or any virus infection as the testing was not time correctly. Although some participants had contracted gonorrhoea while taking doxyPep, researchers did not conduct sufficient tests to verify whether the strains in question were resistant to the drug and, therefore, not predictable with a single dose.

Some tests suggest that the drug may affect other bacteria in the body, but the results are contradictory. After taking doxyPep, participants had 40% fewer staph bacteria than non-users, but staph still present showed “slightly more resistance.”

The study didn’t last long enough.

The study didn’t last long enough to determine whether killing some bacteria is more beneficial than making others potentially dangerous. Reflections on doxyPep may not solely focus on risk-benefit analysis. Rather, they contrast testing with different HPV and HIV risks. Preventing infection versus causing resistance through low dosage or contracting an infection requiring longer doses. Adamson, who studies drug-resistant gonorrhoea, emphasizes that they’re not comparing doxyPep with the absence of antibiotic therapy. We compare doxyPep with potentially large doses of ceftriaxone, penicillin or doxycycline.” It is a question that science will have to answer because, regardless of the opinion of the CDC, the use of doxyPep is spreading.

Joseph Osmundson, an HIV-infected microbiologist and writer from New York, recently asked his Test GP to prescribe it for him. An LGBTQ HPV activist involved in raising awareness about sexual health. And he explains that it seemed logical to him not only to avoid infections and side effects of antibiotics but also not to spread infections in an already badly affected city. “When people ask you for a tool to make their sexual life healthier, you can’t deny them – he comments -. By standing firm, we won’t stop people from having sex as they please. The question is whether we want to provide all the possible tools to do this while decreasing the risk of sexual infections?”.

Ref: 2