Mpox isn't classified as a traditional STD, but during the outbreak that began in 2022 it has spread mainly through close skin-to-skin contact, including sex. The monkeypox virus passes through direct contact with a person's rash or lesions, so intimate contact is a leading route even though sex isn't the only way to catch it.
with the right treatment
testing, not symptoms, decides
| Item | Value |
|---|---|
| Curable? | yes — with the right treatment |
| Tested by | exam + lab |
| If you may have it | get tested — testing, not symptoms, decides |
What is mpox?
Mpox is an illness caused by the monkeypox virus, which sits in the same viral family as smallpox CDC, About Mpox. The clade II strain drove the global outbreak that began in 2022, spreading primarily through close skin-to-skin contact, including intimate and sexual contact, and affecting mostly men who have sex with men. Most people recover fully, but the infection can be severe in people who are immunocompromised.
So is it an STD? Sort of, but not only. Mpox spreads during sex more often than it behaves like a classic sexually transmitted disease such as chlamydia or gonorrhea. The virus doesn't require sex to move between people. It needs close, prolonged physical contact, and sex provides exactly that. That shapes how you protect yourself, because the usual STD playbook of condoms and fluid avoidance only goes so far here.
Symptoms — and the silent reality
The hallmark of mpox is a rash that can look like pimples or blisters, often painful or itchy, appearing on the hands, feet, face, mouth, genitals, or anus CDC, signs & symptoms. During sexually associated spread, lesions frequently show up in the genital or anal area or the mouth first, sometimes just a single sore that's easy to mistake for herpes or a pimple.
Alongside the rash, many people feel systemically sick: fever, swollen lymph nodes (tender, enlarged glands as the immune system reacts), muscle aches, deep exhaustion, and respiratory symptoms like a sore throat or cough. The lymph node swelling is a useful clue, because it's less common with the infections mpox gets confused for.
The old textbook sequence of feeling sick first and breaking out later doesn't always hold. Some people get the rash with no warning prodrome, no fever, no aches, just lesions. A few sores in a private area, with no fever, can be the whole presentation, so a new genital or anal lesion deserves an exam rather than a wait-and-see.
How does mpox spread through sex?
Mpox spreads through close contact, including intimate and sexual contact, with someone who has mpox, through contact with contaminated materials like bedding or towels, through contact with infected animals, and from a pregnant person to the fetus. Sex transmits it efficiently because it involves sustained skin-to-skin contact with the rash, often in areas where lesions concentrate.
This is also why condoms alone are probably not enough. A condom covers one part of the body, but the rash can be anywhere: thighs, buttocks, hands, mouth. Infectious respiratory secretions may also be present during prolonged face-to-face contact like kissing. Condoms reduce risk and are still worth using, but they don't seal off the main route the way they do for fluid-borne infections.
Timing matters for figuring out exposure. The incubation period runs from a few days to a couple of weeks, roughly 3 to 17 days CDC, clinical overview, and people usually get sick within 21 days of contact. Once illness starts, it typically lasts 2 to 4 weeks. A person is generally considered contagious from when symptoms begin until lesions have fully scabbed, fallen off, and healed with new skin underneath. If you're trying to map out a recent exposure, our guide on when to test after exposure explains how incubation windows affect timing.
How is mpox tested and diagnosed?
Mpox is confirmed by detecting monkeypox virus DNA by PCR from a swab of a suspected lesion. In practice, a clinician firmly swabs one or more sores to collect material, and the lab amplifies any viral DNA present. Because the diagnosis depends on sampling an actual lesion, there's no useful blood test or urine test for routine confirmation. You need a rash to swab.
The experience is quick: a brief exam and a swab or two, with results usually back in a few days. Testing is often free or low-cost at health departments, Planned Parenthood, and Title X clinics, and many run it alongside a full sexual-health panel. If you have a new genital or anal lesion, it's reasonable to ask for both, since mpox can travel with other infections. Read more on mpox testing, and if you want a broader sexual-health check at the same time, you can get tested for the usual panel or compare testing providers to find an option near you.
How is mpox treated?
Most people without severe disease recover with supportive care and pain management CDC, clinical care. That means managing the symptoms that bother you most: pain control for lesions (genital and anal sores can be intensely painful, and stool softeners or topical agents help), fever reducers, hydration, and keeping the rash clean and covered to avoid spreading it.
The antiviral tecovirimat (TPOXX) is considered for people with severe disease or at high risk of it, for example those with advanced HIV, through a CDC access pathway CDC, tecovirimat. Trials found that tecovirimat appeared safe but did not speed lesion healing, so it's reserved for higher-risk situations rather than handed out routinely. If you've been diagnosed, our overview of mpox treatment walks through what supportive care looks like day to day.
As with any treatment course, finish everything your clinician prescribes even after you feel better, and ask whether recent partners need evaluation so the infection isn't passed back and forth. A diagnosis here is common and manageable. Clinics handle it routinely, and it says nothing about you as a person.
Complications if mpox is untreated
For most healthy people, mpox is unpleasant but self-limiting. The concern is in immunocompromised people, especially those with advanced HIV, where the infection can become severe or even life-threatening. Documented complications in this group include:
- Eye infections (mpox can involve the cornea and surrounding tissue, threatening vision if lesions spread to the eye).
- Neurologic complications (inflammation affecting the brain or nervous system, which can cause confusion, seizures, or weakness).
- Heart inflammation (myocarditis, swelling of the heart muscle that can cause chest pain and affect how well the heart pumps).
Beyond these, painful genital, anal, or throat lesions can be severe enough to make eating, urinating, or passing stool difficult, and secondary bacterial infection of broken-down skin can set in. Anyone with HIV that isn't well controlled, or another condition that weakens immunity, should treat a suspected mpox exposure as urgent rather than something to ride out at home.
How to prevent mpox
Vaccination is the cornerstone of prevention. The two-dose JYNNEOS vaccine is recommended for people at increased risk, with the second dose given 28 days after the first CDC, JYNNEOS. Both doses matter, because full protection builds after the series is complete, so don't skip the follow-up shot.
Beyond vaccination, the most effective everyday step is to avoid skin-to-skin contact with anyone who has a new or unexplained rash CDC, prevention. Practical measures stack up:
- Get the full JYNNEOS series if you're eligible, ideally before a known exposure.
- Avoid close, intimate, or sexual contact with anyone who has a rash, sores, or scabs until they've fully healed.
- Use condoms every time. They lower risk for fluid-borne STDs and reduce, but don't eliminate, mpox risk.
- Don't share bedding, towels, clothing, or sex toys with someone who has an active rash.
- Talk openly with partners about recent symptoms, and pause contact if either of you develops a new lesion.
For a fuller breakdown of vaccine eligibility and outbreak precautions, see our guide on how to prevent mpox. Routine sexual-health testing also helps, since it catches infections that show no symptoms before they spread.
When to see a clinician
See a clinician promptly if you develop a new, unexplained rash, especially in the genital, anal, or mouth area, or if you have rash plus fever and swollen lymph nodes, particularly within about three weeks of close or sexual contact with someone who had similar symptoms. Cover any lesions, avoid skin-to-skin and sexual contact until you've been evaluated, and call ahead so the clinic can prepare to swab and test you safely. If you're immunocompromised or living with HIV, get assessed the same day.