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Mpox

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Last updated April 8, 2025

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Mpox cases continue to be seen in Colorado

Number of human cases

2022 

2023

2024

2025

405

15

109

10

 New cases are added as they are reported.

Mpox is a virus in the orthopox family of viruses, which includes smallpox. Mpox can cause serious illness.

There are two main clades of mpox, clade I (endemic in Central and Eastern Africa) and clade II (endemic in Western Africa). Clade IIb is responsible for the global mpox outbreak which began in 2022 and is ongoing. Clade IIb has been primarily transmitted from person to person through close and intimate contact, especially during sex. Clades Ia and Ib are responsible for ongoing outbreaks in Central and Eastern Africa with sporadic travel-related cases in other parts of the world, including the U.S.

The risk of clade I mpox to the general population in the U.S. remains very low. However, there has been a continued increase in clade I mpox cases reported in the Democratic Republic of Congo (DRC) during 2023-24, including in cities where it could spread quickly, as well as transmission within neighboring countries. Several travel-associated cases have been detected without sustained transmission in other parts of the world, including the U.S.

Mpox can be transmitted from person to person when someone who has mpox has close contact with someone else. Close contact includes sex or touching the sores, bumps, or lesions of someone who has mpox. Brief interactions without physical contact, like you might have during travel, are not likely to result in getting the virus.

Anyone can get mpox. The virus does not discriminate against any group. During the current global outbreak of clade II mpox, men who have sex with men have been at higher risk for contracting mpox. Transgender women and gender-diverse people have also been disproportionately affected.

Know the symptoms of mpox:

  • New rash or bumps on the skin that may be located on the hands, feet, chest, face, mouth, or near the genitals or in the rectum.
    • The rash can look like pimples or blisters and may be painful or itchy.
    • The rash goes through several stages, including scabs, before healing.
  • Flu-like symptoms, like fever, chills, headache, fatigue, and muscle aches.

People with a new rash or bumps who think they may have been exposed should get tested for mpox, even if they have been vaccinated against mpox or have already had mpox. Health care providers can assess if people severely ill with mpox might benefit from treatment with a drug called tecovirimat (TPOXX), which is available only through CDC via an Investigational New Drug (IND) protocol, or from other therapeutics.

People without mpox symptoms who have been exposed to a person with mpox should receive a mpox vaccine as soon as possible, ideally wiithin four days of exposure. Getting a mpox vaccine between four and fourteen days after exposure may still provide some protection against mpox.

For all travelers to areas with transmission of mpox, including clade I mpox currently circulating in Central and Eastern Africa: 

  • Consider getting vaccinated against mpox if you are at high risk for exposure. Learn more about travel vaccine recommendations and find an mpox vaccine provider on the Where to get vaccinated for mpox webpage.
  • For travelers to areas of Central and Eastern Africa where clade I mpox is circulating, protect yourself by: 
    • Learning more about which activities may increase your risk for mpox and how you can reduce your risk of mpox, including getting vaccinated.
    • Avoiding close contact with people who are sick with signs and symptoms of mpox, including those with skin or genital lesions.
    • Avoiding contact with dead or live wild animals, such as small mammals (including rodents such as rats and squirrels) and non-human primates (monkeys, apes). 
    • Avoiding contact with contaminated materials used by sick people, like clothing, bedding, or materials used in health care settings. 
    • Avoiding materials that came into contact with wild animals.
    • Avoiding eating or preparing meat from wild animals (bushmeat), or using products made from wild animals (creams, lotions, powders).
  • Seek medical care immediately if you develop new, unexplained skin rash (lesions on any part of the body), with or without fever and chills, and avoid contact with others. Tell your doctor or health care provider where you traveled during the last 21 days before developing symptoms. This information is important so testing is done quickly and clade-specific testing is ordered, if needed.

Learn more about mpox

If you have mpox

Learn what steps to take if you have mpox.

Mpox vaccine

Getting vaccinated is the best way to prevent mpox. Find a vaccine provider near you.

Resources for health care providers

Find information for healthcare providers.

Resources for schools and child cares

Find information for schools and child care providers.