December 11, 2024

Clade I Mpox Outbreak Originating in Central Africa

Since January 1, 2024, the Democratic Republic of the Congo (DRC) and many neighboring countries have reported more than 50,000 suspected mpox cases and more than 1,000 suspected deaths.
Of these, about 9,000 cases have been confirmed through laboratory testing, with more than 40 confirmed deaths.
There have also been travel-associated cases in Canada, Germany, India, Kenya, Sweden, Thailand, the United Kingdom, the United States, Zambia, and Zimbabwe.
The risk of clade I mpox to the general public in the U.S. remains low.

CDC is working with international partners to respond to clade I mpox

Since January 1, 2024, the Democratic Republic of the Congo (DRC) and many neighboring countries have reported more than 50,000 suspected mpox cases and more than 1,000 suspected deaths.
Of these, about 9,000 cases have been confirmed through laboratory testing, with more than 40 confirmed deaths.
There have also been travel-associated cases in Canada, Germany, India, Kenya, Sweden, Thailand, the United Kingdom, the United States, Zambia, and Zimbabwe.
The risk of clade I mpox to the general public in the U.S. remains low.

Situation summary

In the United States

The first case of clade I mpox in the United States was detected in November 2024, and was related to the outbreak in Central and Eastern Africa. No additional cases were reported.

CDC has assessed the risk to the United States posed by the clade I mpox outbreak in Central and Eastern Africa. The risk to the general population is assessed as low. The current risk to gay, bisexual, and other men who have sex with men (MSM) who have more than one sexual partner, and people who have sex with MSM partners, is assessed as low to moderate. The risk might change as more information becomes available.

CDC mpox prevention recommendations‎

Learn more about which activities may put you at increased risk of exposure when you travel to a country where clade I MPXV is spreading.

CDC has updated prevention and vaccination recommendations for people traveling to countries with clade I outbreaks. As of December 11, 2024, these countries include Burundi, Central African Republic, Democratic Republic of the Congo, Republic of the Congo, Rwanda, and Uganda.

In the Democratic Republic of the Congo

There are several outbreaks happening at the same time in DRC, with cases reported throughout the country, in the capital city of Kinshasa, and in some other large cities.
Clade Ia mpox cases are impacting the western part of DRC. Although most cases have not been laboratory-confirmed, available data indicate that clade Ia MPXV is spreading through multiple modes of transmission, including contact with infected dead or live wild animals, household contact often involving crowded households, or sexual contact.
Clade Ib mpox cases were recently identified in eastern DRC. Available data indicate that these cases are mostly spreading through intimate or sexual contact between adults at first, then spread likely occurs within households, including to children.

More about mpox cases and outbreaks‎

Learn more about mpox in the United States and around the world on the Mpox Current Situation page.

CDC has been supporting DRC mpox research and response for more than 20 years. CDC and other U.S. government agencies are on the ground in DRC helping partners in the country with disease surveillance, laboratory capacity including testing materials, strengthening workforce capacity, case investigation, case management, infection prevention and control, border health, and risk communication and community engagement. DRC has approved the use of vaccines in-country, so CDC is working with other U.S. government agencies and partners on a strategy for vaccination in DRC.

In Central and Eastern Africa

Map of Central and Eastern Africa showing countries with endemic and non-endemic mpox — Mpox cases are occurring in several countries in Central and Eastern Africa

Public Health Emergency of International Concern Declaration‎

On August 14, 2024, the World Health Organization (WHO) declared the outbreak a Public Health Emergency of International Concern (PHEIC). This is the WHO's highest level of global alert, and the decision recognizes the potential threat this virus poses to countries around the world. Read more about the United States Government's response to the outbreaks in several African countries.

The Republic of the Congo (ROC), which borders DRC to the west, declared a clade I mpox outbreak in April 2024.
There have also been confirmed clade I cases in Central African Republic (CAR), which borders DRC to the north.
Clade I mpox occurs regularly in ROC and CAR, but the new cases appear to be linked to spread from DRC.
In late July 2024, the disease spread to countries that are not known to be endemic for the virus that causes mpox: Burundi, Rwanda, and Uganda, which sit on the eastern border of DRC, and Kenya, which has reported cases of travel-associated mpox only.
Person-to-person transmission has occurred during this outbreak, including through sexual contact, household contact, and within healthcare settings, when personal protective equipment was not available.

CDC is working with Ministries of Health and in-country partners across the region on disease surveillance, laboratory capacity including testing materials, strengthening workforce capacity, case investigation, case management, infection prevention and control, border health, and risk communication and community engagement.

two women stand by a table covered in boxes, which contain laboratory testing supplies for mpox — CDC staff in Burundi with donated laboratory supplies to be used for mpox testing

Cases reported after travel to areas with clade I outbreaks

Kenya - July 2024; travel-associated cases without onward spread continue to be reported
Sweden - August 2024; first clade I mpox case to be reported outside of the African continent
Thailand - August 2024
India - September 2024
Germany - October 2024
The United Kingdom announced a travel-associated case in October 2024; three additional cases from the same household were reported in November 2024.
Zambia - October 2024
Zimbabwe - November 2024
United States - November 2024
Canada - November 2024

A single person with mpox is not cause for widespread concern, since public health authorities can quickly identify, isolate, and treat the person or family, and the risk of spread to other people and households can be minimized. Rapid response measures, such as contact tracing and vaccination, can effectively contain disease in these situations.

Notes: Case data reported in humans to WHO since January 1, 2024, are provided for situational awareness and subject to change. Confirmed cases include those laboratory-confirmed as monkeypox virus and may include cases only confirmed as orthopoxvirus. For more information and additional limitations, see WHO-reported data at 2022-24 Mpox (Monkeypox) Outbreak: Global Trends (shinyapps.io).

Source: 2022-24 Mpox Outbreak: Global Trends. Geneva: World Health Organization, 2024. Available online: https://worldhealthorg.shinyapps.io/mpx_global/ (last cited: August 27, 2024)