STIs: the complete guide for gay and bi men and MSM

What is an STI?

An STI (sexually transmitted infection, formerly STD) is an infection that passes from one person to another during sex: penetration, oral sex, rimming, sometimes just skin-to-skin contact. WHO counts more than 30 bacteria, viruses and parasites that can be sexually transmitted, 8 of them major:

• 4 curable: syphilis, gonorrhoea, chlamydia, trichomoniasis;
• 4 viral, not curable but controllable: hepatitis B, herpes, HIV, human papillomavirus (HPV).

According to WHO, more than one million curable STIs are acquired every day worldwide.

Why are gay and bi men more affected?

It isn’t about “morals”, it’s about networks: in a smaller population with more partners on average, infections spread faster. The anal lining is also more fragile. In France, Santé publique France recorded a +40% rise in gonorrhoea among men between 2022 and 2024.

The STIs to know

STI	Mainly caught through	Curable?	Vaccine?
Syphilis	contact with a sore (anal, oral)	yes, penicillin	no
Gonorrhoea	anal, oral sex, rimming	yes, antibiotic	no
Chlamydia / LGV	anal sex, oral sex	yes, antibiotic	no
Hepatitis A	rimming, mouth-to-anus contact	clears on its own	yes
Hepatitis B	semen, blood, sex	treatment	yes
Hepatitis C	blood (fisting, slamming, SM)	yes, antivirals	no
HPV / warts	skin-to-skin, anal, oral	lesions treated	yes
Herpes	skin-to-skin, even without sores	controlled	no
Mpox	skin-to-skin contact	clears, sometimes severe	yes
Mycoplasma genitalium	penetration	yes, if symptoms	no
Shigella	rimming, faecal contact	yes, resistance rising	no
Pubic lice, scabies	body contact, bedding	yes, topical treatment	no

STIs often go unnoticed

Sexosafe stresses that most STIs caught through oral sex or rimming cause no symptoms, especially in the throat and anus. You can pass them on without knowing. Hence the importance of throat, anal and urine swabs, not just a blood test.

Another key point: having an STI roughly triples the risk of getting or passing on HIV (Sexosafe).

How to protect yourself?

1. Condoms for penetration, and even for oral sex if you want to reduce risk (how to use them).
2. Vaccines: hepatitis A and B, HPV, mpox (schedule).
3. Regular testing: every 3 months with several partners (where and how).
4. Tell your partners if you have an STI, to stop transmission chains.
5. In some cases, doxyPEP, to discuss with a doctor.

PrEP and TasP protect against HIV, not other STIs.

I have a symptom, what should I do?

Discharge, burning, a spot, a sore, itching, anal pain: see a doctor or sexual health clinic without waiting, and avoid sex in the meantime. See the symptoms that should alert you.