Clade I Monkeypox Outbreaks

Outbreak overview

In the United States

• Since November 2024, there have been 10 reported cases of clade I monkeypox in the United States. These cases were in people who had recently traveled to areas associated with the outbreak in Central and Eastern Africa, or who were linked to people who'd traveled from these areas.
  • This number includes three clade I monkeypox cases reported in October 2025 in people with no recent travel. Viral genomic (DNA fingerprint) data indicate that these three cases are linked to a different U.S. case reported in August 2025 following travel to an area with a known clade I monkeypox outbreak.

In Central and Eastern Africa

• Clade Ia monkeypox outbreaks began impacting western areas of the Democratic Republic of the Congo (DRC) in 2024.
  • Available data indicate that clade Ia monkeypox has spread through sexual contact, regular household contact, and encounters with infected dead or live wild animals.
• Clade Ib monkeypox cases initially impacted eastern areas of DRC in late 2023.
  • This subclade has driven much of the spread throughout Central and Eastern Africa and most travel-associated cases to other parts of the world.
  • Available data indicate that these cases most spreading through heterosexual intimate or sexual contact between adults at first, then spread likely occurred within households, including to children.
    
• The disease spread in 2024 and 2025 to neighboring countries of DRC, only some of which are endemic for the virus that causes monkeypox, and sustained local spread occurred.

Outside Central and Eastern Africa

• Several countries in other parts of Africa, Asia, Europe, North America, and South America, as well as Australia, have confirmed clade I monkeypox cases mostly in travelers who'd recently been in areas with clade I outbreaks.
  • To date, there have been more than 150 clade Ib cases in high-income countries, and no deaths have been reported.
  • Beginning in Fall 2025, several countries in Western Europe began reporting clade Ib monkeypox cases among individuals who had no documented history of international travel. These cases were likely related to intimate or sexual exposure among men who have sex with men. We expect additional cases in Europe and the United States.
    
• 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 stop disease spread in these situations.
• For data since January 1, 2024, see global data at 2022-24 Monkeypox (Monkeypox) Outbreak: Global Trends (shinyapps.io). Confirmed cases include those that are laboratory confirmed as monkeypox virus and may include cases only confirmed as orthopoxvirus. These data are provided for situational awareness and are subject to change.

Clade I monkeypox and children

Early in the Central and Eastern African outbreak, a high proportion of suspected cases in some areas were reported in children younger than 15 years of age. Historically, cases of monkeypox in children where monkeypox occurs regularly often happen after contact with wild animals that carry the disease. People then can spread the disease to close contacts, including in their households. The number of children with suspected monkeypox in this outbreak is probably due to spread within and between close households, the large number of younger people in affected countries, misdiagnosis of other diseases (such as measles), poor sanitary conditions, limited access to health services, and a high level of food insecurity and malnutrition.

Based on what we know today, we don't expect to see the same sort of pattern in the United States for several reasons, including smaller household sizes, access to cleaning and disinfecting products, and improved access to medical care, equipment, and information about preventing spread while caring for patients.

It's also worth noting that there are no consistent reports of schools as drivers of monkeypox transmission during the recent outbreaks in Africa, nor any reported school-related monkeypox cases from the clade II outbreak that began in 2022.

If cases of clade I monkeypox do happen in children the United States, CDC has clinical and public health guidance for reporting, testing, and effective case management.

What CDC is doing

CDC has been supporting DRC monkeypox research and response for more than 20 years. CDC and other U.S. government agencies have continued working with partners in the country on disease surveillance, building local laboratory capacity, strengthening public health and laboratory workforce capacity, case investigation, case management, infection prevention and control, border health, and risk communication and community engagement. CDC and other agencies worked with DRC to approve and form a strategy for the use of vaccines in-country that began in October 2024.

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

Resources