This is the ‘morning-after’ pill for STDs that could beat Britain’s rising rates of potentially life-threatening syphilis

A single-dose ‘morning after’ pill could be introduced to tackle rising rates of syphilis in Britain.

New guidelines are being drawn up on the use of doxyPEP – the antibiotic doxycycline – which research shows can be given within 24 hours of unprotected sex to prevent the potentially life-threatening sexually transmitted infection (STI) developing.

Experts say the approach could be “a valuable tool” in the fight against syphilis, which was nearly eradicated in Britain in the 1990s but has resurged in recent years.

Doxycycline, which costs pennies, is already prescribed to treat syphilis and chlamydia, another STD, and is usually taken every day for up to two weeks to eradicate the infection. However, research into the effect of a single high dose has shown that it can stop infections.

The study involved approximately 500 participants who had had an STD in the past year. Some were given doxyPEP after intercourse without a condom – including oral sex – in addition to the standard care of regular quarterly STD testing and treatment if an infection was detected. Others received standard care without doxyPEP.

The risk of a syphilis infection – which can cause serious heart and brain problems – was almost 90 percent lower in the doxyPEP group and the number of STD infections fell by two-thirds overall.

In October, US regulators the Centers for Disease Control (CDC) released guidelines recommending doxyPEP to reverse the country’s syphilis crisis. Since 2018, the number of cases has increased by 80 percent. The sharpest increases have occurred in the most deprived areas, where access to health care is scarce.

The biggest concern in the US is that the disease can be passed from mothers to babies during pregnancy or shortly after birth.

This is known as congenital syphilis and can have tragic consequences including miscarriage, stillbirth, infant death and lifelong medical problems.

In 2022, more than 3,700 babies were born with syphilis in the US.

The risk of syphilis infection – which can cause serious heart and brain problems – was almost 90 percent lower in the doxyPEP group and the number of STD infections fell by two-thirds overall

“The US has a major problem with congenital syphilis, and that is what we are most concerned about if cases continue to rise,” said Dr. John McSorley, a London-based consultant in genitourinary and HIV medicine.

‘In Britain it is mainly men who have sex with men.’

Last month it was reported that sexual health services in England were experiencing an ‘unprecedented’ increase in demand. According to the Local Government Association (LGA), two-thirds of local council areas saw a rise in cases of syphilis and gonorrhea. Overall, there was a 76 percent increase in syphilis rates and a 36 percent increase in chlamydia rates.

An LGA analysis found that between 2015 and 2024, the public health grant received by councils was reduced by £880 million, resulting in a reduction in STD testing, contraception and treatment.

Professor Matt Phillips, chairman of the British Association for Sexual Health and HIV (BASHH), which is responsible for drawing up guidelines on sexual health treatments for doctors, said the working groups were “ensuring” that guidelines for doxyPEP were produced for Britain were drawn up.

“We’re trying to understand who it might be useful for,” he said. “It will be a useful tool for the right people.” He added that the “specter” of drug-resistant superbugs looms large. In Britain, another common infection, gonorrhea, is increasingly immune to doxycycline and other first-line antibiotics.

Antibiotic resistance occurs when bacteria are exposed to drugs but are not completely killed by them, which can happen if patients do not complete the course.

Last month it was reported that sexual health services in England were experiencing an ‘unprecedented’ increase in demand

Surviving bacteria can develop defense mechanisms against the antibiotic. Once these multiply, they are much more difficult to treat.

‘There is a concern that if people use doxyPEP while unknowingly having gonorrhea, this could worsen drug resistance,’ says Prof Phillips. ‘We should ensure that patients receiving doxyPEP have regular check-ups.’

Dr. McSorely added that doxyPEP would be recommended in addition to standard approaches. “It can take up to three months for syphilis to cause symptoms, and during that time people can unknowingly pass on the disease,” he said.

‘We recommend that all sexually active people get tested once a year, and if you have had a new partner, get tested as well.

‘If it is picked up, we will have 100 per cent effective treatments and we can do contact tracing, which is the best way to catch the infection in people who are asymptomatic.

‘A third of people diagnosed with syphilis had no idea anything was wrong. We also encourage the use of condoms as they are very effective in preventing most STDs.”

Some private clinics online promote doxyPEP, claiming it is ‘a no-brainer’ to prevent syphilis.

But Dr. McSorley urged caution. ‘The dose in doxyPEP is high; on an empty stomach it would probably make you throw up,” he said. ‘It can also cause photosensitivity, when the skin blisters when exposed to even mild sunlight.’