Mpox virus

What is Mpox?

Mpox (previously known as monkeypox) virus belongs to the Orthopoxvirus genus which also includes variola virus (which causes smallpox), vaccinia virus (used in the smallpox vaccine), and cowpox virus, among others.

Transmission occurs when an individual comes into contact with the virus from an animal, human, or materials contaminated with the virus. The virus enters the body through broken skin (even if not visible) or through the respiratory tract (eyes, nose, or mouth). Human-to-human transmission is thought to occur primarily through skin-on-skin, intimate personal contact. The virus also can be transmitted by large respiratory droplets requiring prolonged face-to-face contact.

The natural reservoir of mpox remains unknown. However, African rodents and non-human primates (like monkeys) may harbor the virus and infect people.

How mpox spreads


Mpox was first discovered in 1958 when two outbreaks of a pox-like disease occurred in colonies of monkeys kept for research. The first human case was recorded in 1970 in the Democratic Republic of the Congo during a period of intensified effort to eliminate smallpox. In Africa, mpox has been shown to cause death in as many as 1 in 10 persons who contract the disease.

According to the Centers for Disease Control and Prevention (CDC), thousands of cases have been reported in the US, particularly among men who have sex with men. CDC is urging US healthcare professionals to be alert for patients who have rash illness consistent with mpox, regardless of travel history, risk factors, or gender or sexual orientation.


In humans, the symptoms of mpox are similar to, but milder than, the symptoms of smallpox. Mpox symptoms include:

  • Rash on the hands, feet, chest, face, mouth, or on or near the genitals or anus. The rash may start out looking like pimples or blisters and may be painful or itchy.
  • Fever or chills
  • Swollen lymph nodes
  • Exhaustion
  • Muscle aches, backache, headache
  • Respiratory symptoms (e.g., sore throat, nasal congestion, or cough)

Symptoms usually start within 3 weeks of exposure to mpox. Within 1 to 3 days (sometimes longer) after the appearance of fever, the infected individual develops a rash. The rash can appear anywhere on the body, often on the trunk, genitals, or buttocks. The illness typically lasts for 2−4 weeks.

A person with mpox can spread it to others from the time symptoms start until the rash has fully healed and a fresh layer of skin has formed. Some people can spread mpox to others from 1-4 days before their symptoms appear.

Mpox Symptoms


Vaccination is an important tool in preventing the spread of mpox. In addition, mpox infection can be prevented by:

  • Avoiding close, skin-to-skin contact with the mpox rash
  • Avoiding contact with objects and materials that a person with mpox has used (such as bedding, towels, clothing, or eating utensils or cups)
  • Washing hands with soap and water or using an alcohol-based hand sanitizer after contact with infected animals or humans
  • Avoiding contact with animals that could harbor the virus (including animals that are sick or that have been found dead in areas where mpox occurs) and any materials that have been in contact with a sick animal
  • Isolating infected patients from others who could be at risk for infection

CDC recommends vaccination for people who have been exposed to mpox or may be more likely to get mpox. JYNNEOSTM, an attenuated live virus vaccine, is effective in protecting people against mpox. Vaccine supply is limited but vaccines may be available through state and local health departments.

Mpox is often transmitted through close, sustained physical contact, almost exclusively associated with sexual contact in the current outbreak. Condoms can help protect against mpox but may not prevent all exposures because the rash can occur on other parts of the body. CDC recommends limiting the number of sexual partners to reduce the risk of exposure. If you or a partner think you may have mpox, avoid kissing, touching, or sex of any kind (oral, anal, or vaginal) while you are sick.


Currently, there is no proven, safe treatment for mpox virus infection, and treatment focuses on relieving symptoms. Pain management is critical. The majority of patients recover from mpox, but it may take 2-4 weeks for the rash to disappear.

Vaccines (JYNNEOSTM and ACAM2000®), antivirals, and vaccinia immune globulin (VIG) may be used to control the Mpox outbreak in the US. An experimental antiviral drug (tecovirimat or Tpoxx) is available in the US under “compassionate use.”

If you think you may have mpox, talk to a healthcare professional as soon as possible.

Updated March 2023

Source: Centers for Disease Control and Prevention


Related Resources

Mpox Prevention Webinar Presenters
August 15, 2023 11:00 am

Mpox Prevention through Vaccination

In this recorded webinar, speakers discuss the epidemiology of mpox and the importance of vaccination to help prevent mpox outbreaks. Speakers will discuss best practices and communication strategies to increase vaccination rates in the US, particularly among at-risk populations …

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June ACIP Meeting Updates Webinar Presenters
July 12, 2023 12:00 pm

Updates from June 2023 Advisory Committee on Immunization Practices (ACIP) Meeting

In this recorded webinar, speakers discuss updates from the June 2023 Advisory Committee on Immunization Practices (ACIP) meeting. Hear about the latest updates regarding US vaccination recommendations for children, adolescents, and adults …

Learn More