Gonorrhoea: Causes and Risk Factors

Gonorrhoea is caused by a bacterium, not by poor hygiene, toilet seats, or swimming pools. Understanding exactly how it spreads, and what increases your risk, helps you make better decisions about testing and prevention.

UK gonorrhoea rates have risen sharply since 2019. UKHSA data shows record numbers of diagnoses, driven in part by increased testing but also by genuine increases in transmission. If you are sexually active, this is relevant to you.

"Antibiotic resistance is a growing concern with gonorrhoea. Current BASHH guidelines specify intramuscular ceftriaxone as first-line treatment — this is why a clinic visit, rather than a home kit, matters."

Dr Mohammad Bakhtiar, Sexual Health Physician, GMC 4694470

What causes gonorrhoea?

Gonorrhoea is caused by the bacterium Neisseria gonorrhoeae, transmitted through unprotected vaginal, anal, or oral sex with an infected person; the bacteria infect the mucous membranes of the urethra, cervix, rectum, and throat, and can also be passed from mother to baby during childbirth.

The bacterium cannot survive outside the human body for more than a few seconds. You cannot catch gonorrhoea from casual contact, shared objects, food, or water. It requires direct mucosal contact.

How gonorrhoea spreads

Gonorrhoea transmits through infected bodily fluids (semen, pre-ejaculate, vaginal secretions) and through direct mucosal contact with an infected site.

Vaginal sex is the most common transmission route worldwide. An infected man can transmit gonorrhoea to a female partner during a single act of unprotected vaginal intercourse with a transmission probability estimated at 50-70% (female to male transmission is lower, around 20-25% per act).

Anal sex carries a high transmission risk, particularly for the receptive partner. Rectal gonorrhoea is common in men who have sex with men and in women who have receptive anal sex. The rectal mucosa is highly susceptible to infection.

Oral sex transmits gonorrhoea to and from the throat. Performing oral sex on an infected partner can result in pharyngeal (throat) gonorrhoea. Receiving oral sex from a partner with pharyngeal gonorrhoea can result in urethral or cervical infection. Pharyngeal gonorrhoea is typically asymptomatic, which makes it a hidden reservoir for ongoing transmission.

Genital-to-genital contact without penetration can transmit gonorrhoea if infected discharge comes into contact with a partner's mucosal surfaces, though this is less efficient than penetrative sex.

Mother-to-baby transmission during vaginal delivery can cause gonococcal ophthalmia neonatorum, a serious eye infection in newborns. This is one of the reasons routine STI screening during pregnancy is standard.

Sharing sex toys can transmit gonorrhoea if toys are shared between partners without cleaning or without using a new condom between users.

What does NOT cause gonorrhoea

This question comes up regularly, so it is worth being direct. The page on non-sexual transmission of STIs covers this in more detail, but the key points for gonorrhoea:

You cannot get gonorrhoea from toilet seats, swimming pools, hot tubs, doorknobs, or shared towels. The bacterium dies almost immediately outside the human body.

Kissing does not transmit gonorrhoea (though there is emerging research on pharyngeal gonorrhoea and deep kissing; current BASHH guidance does not consider kissing a significant transmission route).

Hugging, handshakes, and general social contact carry no risk.

Having had gonorrhoea in the past does not prevent future infections. There is no acquired immunity.

Risk factors for gonorrhoea

Some people are statistically more likely to be diagnosed with gonorrhoea. Risk factors include:

Age. Gonorrhoea rates are highest in people aged 15-24. This is the most affected demographic in both men and women according to UKHSA surveillance data.

Multiple sexual partners. Each new partner increases the cumulative probability of encountering gonorrhoea. This is simple mathematics, not a moral statement.

Inconsistent condom use. Condoms, used correctly and consistently, reduce gonorrhoea transmission by an estimated 70-80%. They are not 100% effective (they do not cover all potentially infected skin), but they reduce risk substantially.

Men who have sex with men (MSM). MSM account for a disproportionate number of gonorrhoea diagnoses in the UK. This is driven by higher rates of pharyngeal and rectal infection and by sexual network dynamics, not by sexual orientation itself. Our MSM screening packages reflect these specific risk patterns.

Previous STI diagnosis. Having had one STI increases the likelihood of acquiring another. This is partly about shared risk factors and partly about mucosal inflammation from the first infection making it easier for a second pathogen to establish itself. If you have been recently treated for chlamydia or another STI, testing for gonorrhoea is sensible.

A partner diagnosed with gonorrhoea. If a sexual partner has been diagnosed, you should be tested regardless of whether you have symptoms. Partner notification is one of the most effective tools for controlling gonorrhoea spread.

Concurrent HIV infection. People living with HIV have higher rates of gonorrhoea (and other STIs). Co-infection is also clinically relevant because gonorrhoea increases HIV viral shedding, making transmission of HIV more likely.

Sex while travelling. Antibiotic resistance patterns vary by country. Gonorrhoea acquired in parts of Southeast Asia, for example, may be resistant to antibiotics that work against UK strains. If you have had unprotected sex abroad, mention this to your doctor, as it may affect treatment choices.

Substance use during sex. Alcohol and recreational drugs are associated with reduced condom use and increased sexual risk-taking. This is a public health observation, not a judgement.

Antibiotic resistance: why it matters for you

Gonorrhoea has a remarkable ability to develop antibiotic resistance. Over the past 80 years, the bacterium has become resistant to sulfonamides, penicillin, tetracyclines, fluoroquinolones, and most recently azithromycin. Current UK first-line treatment is a single injection of ceftriaxone, and cases with reduced ceftriaxone susceptibility have already been identified.

This matters for two practical reasons:

Oral antibiotics alone are no longer recommended for gonorrhoea in the UK. If you have been given oral ciprofloxacin or azithromycin alone for gonorrhoea by another provider, this may not have cleared the infection. A test of cure 2 weeks after treatment is recommended by BASHH.

Testing is better than empirical treatment. If you have gonorrhoea symptoms (discharge, burning), the correct approach is to test, confirm the diagnosis, and then treat with the right antibiotic. Treating blind with the wrong drug wastes time and may select for further resistance.

We test using PCR methodology, which is the gold standard for gonorrhoea detection. Our UKAS-accredited laboratory partners also perform culture and antibiotic sensitivity testing when clinically indicated, which tells us exactly which antibiotics will work against your specific strain.

Prevention

There is no gonorrhoea vaccine (though research is ongoing, with promising results from meningococcal B vaccine cross-protection studies).

The most effective prevention strategies are:

Consistent condom use during vaginal, anal, and oral sex. Condoms reduce risk by 70-80% for genital gonorrhoea.

Regular testing. If you have new or multiple partners, periodic routine screening catches infections early, before symptoms appear and before transmission to others. BASHH recommends at least annual screening for sexually active people under 25 and for MSM.

Reducing the number of concurrent sexual partners reduces cumulative exposure probability.

Testing before sex with a new partner. This is increasingly common practice. Our screening packages provide comprehensive results within 24 hours (or 6 hours with our FAST Screen), making pre-relationship screening practical.

Open communication with sexual partners about STI status and testing.

Avoiding sharing sex toys, or using condoms on toys and cleaning between users.

Our STI prevention page covers these strategies in more detail.

When to get tested

You should consider gonorrhoea testing if:

• You have unusual discharge from the penis, vagina, or rectum
• You experience painful urination
• A partner has been diagnosed with gonorrhoea or another STI
• You have had unprotected vaginal, anal, or oral sex with a new or casual partner
• You are a sexually active person under 25 (the highest-risk age group)
• You are an MSM with new or multiple partners
• You have had sex abroad, particularly in regions with high STI prevalence
• You have a known exposure to any STI

Testing costs £103.75 for a combined chlamydia and gonorrhoea test with results in 1-3 days. For same-day results, our FAST CT/GC test returns in 6 hours for £75. All screening packages include gonorrhoea testing alongside other common infections.

Walk in to our clinic at 117a Harley Street or book online. No GP referral needed. Pseudonymous registration and cash payment accepted.

Frequently asked questions

Can you get gonorrhoea from kissing?

Current evidence and BASHH guidance do not consider kissing a significant transmission route for gonorrhoea. Some recent Australian research has suggested that deep kissing may contribute to pharyngeal gonorrhoea transmission, but this has not changed UK clinical guidelines. The primary routes remain vaginal, anal, and oral sex.

How common is gonorrhoea in the UK?

Gonorrhoea is the second most common bacterial STI in England after chlamydia. UKHSA reported over 82,000 diagnoses in 2023, a record high. Rates are highest in London and other major cities, and among men aged 20-34 and women aged 15-24.

Can gonorrhoea be prevented with antibiotics taken before or after sex?

There is emerging evidence for doxycycline post-exposure prophylaxis (doxy-PEP, taken within 72 hours of sex) reducing STI risk, including gonorrhoea, in MSM. However, this is not yet standard UK practice, and concerns about driving antibiotic resistance mean BASHH has not formally recommended it. This may change. Discuss with your doctor if you are interested.

If my partner has gonorrhoea, will I definitely catch it?

Not necessarily. Transmission is not 100% per sexual act. For a single act of unprotected vaginal sex with an infected male partner, the female acquisition risk is estimated at 50-70%. Male acquisition from a female partner is lower, around 20-25% per act. Anal sex carries comparable or higher risk. Regardless of the probability, if your partner has gonorrhoea, get tested.

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Think you may have been exposed to gonorrhoea? Walk in for testing at 117a Harley Street with results from 6 hours, or book an appointment online. All screening packages include consultation, examination, and prescription.

References

• UKHSA (2024). Sexually transmitted infections and screening in England: 2023 report.
• UKHSA (2024). Antimicrobial resistance in Neisseria gonorrhoeae in England and Wales.
• BASHH (2024). UK National Guideline for the Management of Gonorrhoea in Adults.