The strange rise of Syphilis cases in heterosexual men in the UK

New data from the UK Health Security Agency (UKHSA) reveals a concerning trend in sexually transmitted infections (STIs) transmission between 2023 and 2024.

While the data did contain some good news, like a decrease in Chlamydia and Gonorrhoea diagnoses, there was a noticeable uptick in Syphilis cases nationwide, with a stark rise in the number of cases found in heterosexual people, particularly heterosexual men.

Keep reading to find out more.

Cases of Syphilis have been rising for several years in the UK. Get tested to protect yourself and the people you care about.

What is Syphilis?

Syphilis is an STI caused by a bacterium that passes between people during sex. It’s usually identified by a distinctive sore (chancre) that appears between 10 and 90 days after the initial infection. This chancre is usually round, firm, and painless, appearing at the site of infection. This is usually the genitals but can also be in the mouth or anus.

The chancre goes away on its own. However, if left untreated, the infection progresses to a secondary phase, where it can cause flu-like symptoms like:

• Body rashes
• Fatigue
• Nausea
• Dizziness
• Body aches
• Fever
• Headaches

It’s easy to confuse these symptoms with less serious infections, which is why Syphilis so often goes untreated.

Syphilis can then progress to a latent stage where it causes no symptoms but slowly damages your organ systems, like the bones, brain, heart, and nerves. If left untreated over the years, Syphilis can be fatal.

How do you get Syphilis?

Syphilis is an STI, so you can get it from most kinds of unprotected sexual activity. Infected bodily fluids, like semen and vaginal fluids, come into contact with mucous membranes in the genitals, anus, and throat, which then absorb the bacteria, giving it passage into your body.

You can also get Syphilis by sharing sex toys without washing them between uses or covering them with condoms.

Since Syphilis is a blood-borne infection, you can also get it through unsterilised tattooing equipment and blood transfusions, though this is very rare in countries with advanced healthcare systems.

Sharing needles for drug use is also known to be a risk factor.

What does the data show?

Cases of Syphilis in England are at their highest level since 1948, according to the UKSHA’s newly released data. 9,513 cases of infectious Syphilis were diagnosed in 2024.

While the majority of cases were diagnosed in gay and bisexual men, there was a much larger proportional rise in Syphilis diagnoses among straight men and women.

There were 1,958 cases diagnosed among heterosexual men and women in 2023, a 23.8% rise from 2022 when there were 1,608 cases.

This is despite the fact that diagnoses of Syphilis in heterosexual women remained relatively stable over the same time period, only increasing by 1%. Including late stage or complications such as ocular and otosyphilis, total diagnoses increased 4.6%.

The largest jumps in diagnoses were in heterosexual men aged between 25 and 64. The number of diagnoses in men who have sex with women in ages 15 to 19 and 65 and over also increased, though at smaller numbers relative to other age groups.

Among heterosexual men, where sex partnerships were reported, Syphilis was most frequently diagnosed in those reporting one recent sex partner (53%).

Among all women, where sex partnerships were reported, Syphilis was most frequently diagnosed among those with one recent sex partner (66.1%).

On the other hand, the number of overall Syphilis cases in gay, bisexual, and other men who have sex with men dropped about 1.6%.

The data also showed significant drops in the number of diagnoses of other STIs. Gonorrhoea diagnoses dropped 15.9% between 2023 and 2024, while Chlamydia diagnoses dropped by 13% in the same time period.

Overall, STI diagnoses dropped 8.8% from 2023 to 2024.

Why is this happening?

It’s not entirely clear what has caused this increase in Syphilis diagnoses.

The UKSHA stated that the number of Syphilis tests increased between 2023 and 2024. This may mean that an increase in testing revealed more existing infections rather than an increase in new infections. This could be the result of shifting testing patterns over time.

To address the increase in Syphilis diagnoses in England, the UKSHA released a Syphilis action plan in 2019. This plan focused on key interventions to control and prevent this infection. These measures included more frequent testing, partner notification, and raising awareness about the infection.

How can I protect myself?

Syphilis can damage your health, so it’s essential to protect yourself in any way you can.

First and foremost, avoid unsafe sex. This includes unprotected sex without barrier contraception, like condoms.

But if you think you may have been exposed to an infection, you should get tested immediately. Book an STI test at a sexual health clinic near you by clicking the button below.

Don’t leave your sexual health to chance. It’s always Better2Know.

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