A sexually transmitted infection can be present without producing the slightest symptom: that is the most common
situation, and it is why these infections circulate. Three habits cover most of the risk.
Condoms, including for oral and anal sex, remain the only protection that works against nearly all of
them. Regular testing, at every change of partner and before stopping condoms in a new relationship,
is the only way to detect what cannot be seen. And vaccines exist against three of them: those against HPV and hepatitis B are highly effective (WHO, 2025), and the mpox vaccine is recommended for people at risk (WHO, 2024).
Everything else depends on the infection: how long after exposure a test becomes reliable, which sample to ask for,
how long treatment lasts and what complications are possible vary a great deal. Each page below sets out those
details.
The infections, one by one
Twelve detailed pages: what the infection is, how it is transmitted, which signs should prompt a check, which test
to ask for and when, what treatment involves, what happens without it, and what to do after a diagnosis.
Unusual discharge, burning on passing urine, persistent itching, a sore, spot or wart on the genitals or around the
anus, pain during sex, unusual bleeding, tender glands: all of these justify a prompt appointment. But the absence of
symptoms rules nothing out — most infections produce none, and someone who feels perfectly well can be infectious.
When to test
At every change of partner, and before stopping condoms in a new relationship.
Once a year for sexually active women under 25 (CDC, 2021), with or without symptoms; for men, depending on risk factors.
More often with multiple partners, asking for throat and rectal swabs according to your practices.
Whenever you have symptoms, and if a partner tells you they have been diagnosed.
In early pregnancy, where several tests are routine.
Once a diagnosis is made
Notifying recent partners is the single most effective step, for them and for you: without it, reinfection is the
rule rather than the exception. Most services will do it on your behalf, anonymously, if the conversation is difficult.
A diagnosis should also prompt a full screen: these infections rarely travel alone.
After a risky encounter
Following a recent exposure carrying a significant risk of HIV transmission, post-exposure
treatment can be prescribed by emergency services. It must begin as early as possible, ideally within four
hours, and is no longer offered beyond 48 to 72 hours. That deadline is the only thing that matters: do not leave it
until tomorrow.
Who to see for this problem?
The page Who to see, and when gives, symptom by symptom, the right professional — family doctor, urologist, gynaecologist, sex therapist, psychologist — and the emergencies that cannot wait.
What about you?
Your last STI test was…
Anonymous vote, no account: results appear after you vote, for all readers, readers of the English site and readers in your country. All the results: the polls page.
Sources
Sexually transmitted infections (STIs) — World Health Organization (WHO), 2025: STIs most often asymptomatic, condom effectiveness, safe and effective vaccines against hepatitis B and papillomaviruses
Mpox — World Health Organization (WHO), 2024: mpox transmitted through close contact, including sexual contact, and existence of recommended vaccines for exposed people
Hepatitis B — World Health Organization (WHO), 2026: sexual transmission of hepatitis B, and a safe and effective vaccine offering almost complete protection
Chlamydial Infections - STI Treatment Guidelines — Centers for Disease Control and Prevention (CDC), 2021: partners of the last 60 days and the last partner beyond that; retesting three months after treatment
Official or institutional documents this page relies on, consulted on 12 October 2026. Links open in a new tab.
Links to official or reference sources. They open in a new tab.
Page checked in . The instruments cited can change: if in doubt, confirm with the official source given.
Text prepared with artificial intelligence, reviewed and checked by the AffectionPlus team (method and sources: About). This content does not replace medical or legal advice. Spotted an error? Write to us.
