Mpox
Mpox (formerly monkeypox) is a viral infection caused by the monkeypox virus, spread through close skin-to-skin contact, including during sex, as well as through respiratory droplets and contaminated items. It typically causes a painful or itchy rash that moves through stages before scabbing over, often with fever, swollen lymph nodes, and body aches. Most cases resolve on their own within a few weeks, but it can be serious for people with weakened immune systems. A vaccine is available for those at higher risk. Here is what mpox is, how it spreads, what the rash looks like, and how it is managed.
- Pathogen
- Monkeypox virus
- Orthopoxvirus family (related to smallpox)
- Curable
- Self-limiting
- Most recover with supportive care
- Incubation
- 3–17 days
- Usually sick within 21 days of contact
- Illness duration
- 2–4 weeks
- Typically resolves on its own
Understanding mpox
What is mpox?
Mpox is caused by the monkeypox virus, a member of the same Orthopoxvirus family as smallpox. The clade II strain drove the global outbreak that began in 2022, which spread primarily through close skin-to-skin contact, including intimate and sexual contact, and affected mostly men who have sex with men.
The hallmark of mpox is a rash that can look like pimples or blisters, often painful or itchy, that may appear on the hands, feet, face, mouth, genitals, or anus. During the recent outbreak, lesions frequently appeared in the genital or anal area or the mouth, which is one reason mpox is often grouped with sexually transmitted infections even though it is not exclusively spread through sex.
Most people recover fully without lasting harm, but mpox can be severe in people who are immunocompromised, especially those with advanced HIV. Because the infection is self-limiting in most cases, treatment focuses on supportive care, with antiviral therapy reserved for people with severe disease or high risk of complications.
Mpox is confirmed by detecting mpox virus DNA using a PCR test on a swab taken from a suspected lesion. Because the rash can mimic other conditions, lab confirmation is important. A two-dose vaccine, JYNNEOS, is recommended for people at increased risk and is a cornerstone of prevention.
Symptoms
What are the symptoms of mpox?
Mpox almost always produces a visible rash, which is the defining feature of the illness. Some people develop the rash with no warning prodrome of fever or other symptoms beforehand. Symptoms usually appear within 21 days of contact, with an incubation period of 3–17 days. The illness typically lasts 2–4 weeks.
Rash and skin signs
- A rash that can look like pimples or blisters
- Lesions are often painful or itchy
- Can appear on the hands, feet, and face
- Frequently appears in the genital or anal area or the mouth
- Some people get the rash with no warning prodrome
Systemic symptoms
- Fever
- Swollen lymph nodes
- Muscle aches
- Exhaustion
- Respiratory symptoms
Because lesions often appear in the genital or anal area or the mouth, mpox can be mistaken for other sexually transmitted infections. A lesion swab tested by PCR confirms the diagnosis.
Left untreated
Why mpox is worth catching early
Eye infections
In immunocompromised people, especially those with advanced HIV, mpox can cause eye infections that may threaten vision.
Neurologic complications
Severe mpox can lead to neurologic complications in people with weakened immune systems.
Heart inflammation
Inflammation of the heart has been reported as a complication, particularly in immunocompromised individuals.
Life-threatening disease
In people with advanced HIV, mpox can become life-threatening, which is why early evaluation and antiviral access matter for high-risk patients.
Treatment
How is mpox treated?
Most people without severe disease recover with supportive care and pain management. Antiviral therapy is reserved for severe disease or people at high risk of complications.
Treat partners
People with mpox should avoid close, skin-to-skin, and intimate contact until lesions have fully healed to prevent spreading the virus to partners.
In pregnancy
Mpox can pass from a pregnant person to the fetus; pregnant individuals with possible exposure or symptoms should seek prompt medical evaluation.
Re-test after treatment
Diagnosis is confirmed by lesion PCR; follow your clinician's guidance on monitoring until the rash resolves.
Prevention
How to prevent mpox
-
Get the JYNNEOS vaccine
The two-dose JYNNEOS vaccine is recommended for people at increased risk. The second dose is given 28 days after the first.
-
Avoid contact with rashes
Avoid skin-to-skin contact with anyone who has a rash that could be mpox.
-
Use condoms, but know the limits
Condoms reduce but don't eliminate risk, because the rash can be on other parts of the body and infectious respiratory secretions may be present.
Who is most at risk
Who is most at risk for mpox?
- Men who have sex with men
- This group was disproportionately affected during the 2022 clade II outbreak, largely through close skin-to-skin and sexual contact.
- People with multiple or new intimate partners
- Close skin-to-skin and intimate contact is a primary route of spread, so frequent new contacts increase exposure risk.
- People with advanced HIV
- Immunocompromised individuals, especially those with advanced HIV, face a higher risk of severe and potentially life-threatening mpox.
Stats & rates
How common is mpox in the U.S.?
The 2022 outbreak affected mostly men who have sex with men, spreading primarily through close skin-to-skin and intimate contact.
- Clade II
- strain behind the 2022 global outbreak
Ready to get tested for mpox?
See test types, turnaround time, cost, at-home options, and clinics near you.
Good to Know
Mpox FAQs
Common questions about mpox, answered.
Is mpox a sexually transmitted infection?
Mpox spreads through close contact, including intimate and sexual contact, which is why it's often discussed alongside STIs. However, it can also spread through contact with contaminated materials, infected animals, and from a pregnant person to the fetus, so it isn't exclusively sexually transmitted.
How is mpox diagnosed?
Mpox is confirmed by detecting mpox virus DNA using a PCR test on a swab taken from a suspected lesion. Because the rash can be visible, a lesion is needed to collect the sample.
What does the mpox rash look like?
The rash can look like pimples or blisters and is often painful or itchy. It may appear on the hands, feet, face, mouth, genitals, or anus, and during the recent outbreak it frequently showed up in the genital or anal area or the mouth.
How long after exposure do mpox symptoms appear?
The incubation period is 3–17 days, and people usually get sick within 21 days of contact. The illness itself typically lasts 2 to 4 weeks.
Is mpox curable?
Most people without severe disease recover fully with supportive care and pain management. The antiviral tecovirimat (TPOXX) is considered for severe disease or those at high risk, such as people with advanced HIV.
Do condoms prevent mpox?
Condoms alone are probably not enough, because the mpox rash can be on other parts of the body and infectious respiratory secretions may be present. Condoms reduce but don't eliminate the risk.
Is there a vaccine for mpox?
Yes. The two-dose JYNNEOS vaccine is recommended for people at increased risk, with the second dose given 28 days after the first.
Who is at risk of severe mpox?
Immunocompromised people, especially those with advanced HIV, can develop severe complications such as eye infections, neurologic complications, and heart inflammation, and mpox can be life-threatening in these individuals.
Medically Reviewed · Updated
Reviewed by Dr. Ngozi Adeyemi, MD, MPH · Infectious Disease & Epidemiology
Board-certified in infectious disease with a focus on STI epidemiology and public-health screening programs. Leads testing, diagnosis and the data-driven 'state of STDs' reporting. Our editorial guidelines →
7 Sources
Data & references
- CDC, About Mpoxhttps://www.cdc.gov/mpox/about/index.html
- CDC, Mpox signs & symptomshttps://www.cdc.gov/mpox/signs-symptoms/index.html
- CDC, Mpox clinical overviewhttps://www.cdc.gov/mpox/hcp/clinical-overview/index.html
- CDC, Mpox treatment (tecovirimat)https://www.cdc.gov/mpox/hcp/clinical-care/tecovirimat.html
- CDC, Mpox vaccines (JYNNEOS)https://www.cdc.gov/mpox/vaccines/index.html
- CDC, Mpox preventionhttps://www.cdc.gov/mpox/prevention/index.html
- CDC, Mpox clinical carehttps://www.cdc.gov/mpox/hcp/clinical-care/index.html
Have a different question? Browse the full STD & STI FAQ library, every question we answer, in one place.