What to know
- There are two types of the virus that causes monkeypox, clade I and clade II. Both types can be spread, treated, and prevented in the same ways.
- Each clade has two subclades (clade Ia and clade Ib; clade IIa and IIb).
- Recent outbreaks of monkeypox have spread initially through intimate or sexual contact. In some cases, monkeypox was then spread within households.
- Recent travel-associated clade I monkeypox cases have almost exclusively been attributed to subclade Ib; there have been no deaths associated with these cases and most people had relatively mild illness.
- The ongoing global outbreak of clade IIb monkeypox that began in 2022 has caused more than 100,000 cases in 122 total countries, including 115 countries where monkeypox was not previously reported.
- CDC has vaccination recommendations for people at risk in the United States or who are traveling to countries with clade I outbreaks or new clade II outbreaks.
Current situation
In the United States
Clade I monkeypox
- The risk posed by the clade I monkeypox outbreak to most people within the United States remains low.
- In the United States, since November 2024, there have been more than 60 laboratory-confirmed cases of clade I monkeypox in at least 20 states. The majority of these cases are among gay, bisexual, or other men who have sex with men. Many of these cases:
- Had recently traveled from areas associated with the outbreak in Central and Eastern Africa;
- Reported sexual contact during travel to parts of Western Europe where newer outbreaks are being reported; OR
- Reported sexual contact with people who had traveled from these areas.
- Since August 2026, an increasing proportion of clade I cases in the United States have been reported in individuals with no recent international travel or known links to people who had recently traveled.
- Cases with presumed domestic transmission have been reported in more than 10 jurisdictions, indicating a likely transition to sustained clade Ib transmission in the United States
- CDC expects to see additional cases of both travel-related and domestically acquired cases of clade Ib occurring across the United States.
CDC continues to monitor both clade II and clade I monkeypox cases across the United States and follow surveillance reports to monitor for any changes in demographics, disease severity, or case counts by jurisdiction. CDC also continues surveillance testing to identify monkeypox clade for all specimens sent to CDC's poxvirus laboratory.
Clade II monkeypox
- Clade II monkeypox is still circulating at low levels.
- Fall 2025 marked the highest monthly case counts since the peak of the outbreak in 2022.
Across the globe
Clade I monkeypox
- Outbreaks of clade I monkeypox in Central and Eastern Africa continue.
- 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 male-to-male sexual contact.
- Other travel-associated cases of clade I monkeypox have been reported from other parts of Africa, as well as Asia, Europe, the Middle East, North America, South America, and Australia.
Recent monkeypox outbreaks have low death rates
During recent outbreaks, death rates ranged from than less than 0.5% (clade Ib) to about 3% (clade Ia). Clade II is the type that caused the ongoing global outbreak that began in 2022. Fewer than 0.1% of people infected with clade II die from the disease.
Clade II monkeypox
For global case data for clade I and clade II monkeypox since January 1, 2024, see Global Mpox Trends. 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.
Cases of clade I monkeypox have been diagnosed worldwide.
Clade II monkeypox is spreading in the United States and around the world.
What CDC is doing
- CDC raises awareness for U.S. healthcare providers, including the latest guidance for diagnosing monkeypox and clinical decision-making.
- CDC continues critical work to protect the United States from emerging and infectious diseases. CDC has collaborated closely with key partners in affected countries to help support efforts to stop monkeypox at the source.
- CDC works closely with U.S. state, tribal, local, and territorial public health departments to provide recommendations for clinical management, diagnosis, and prevention of domestic monkeypox cases. in the U.S.
- CDC continually increases capacity in communities across the United States for early detection of monkeypox through existing surveillance systems, including wastewater testing.
- CDC raises awareness for healthcare providers, including the latest guidance for diagnosing monkeypox and clinical decision-making.
- CDC collaborated with governmental and civil society partners in affected countries to collect and analyze case data, and to identify how monkeypox is spreading.
- CDC coordinated technical assistance in response to urgent in-country needs, including: increasing the number of monkeypox testing sites; improving specimen transport networks to quickly identify new cases; assisting with Ministry of Health-led vaccine implementation; strengthening emergency management systems; improving case surveillance; and training healthcare workers.
- CDC's staff throughout Africa provide critical, real-time information to inform U.S. preparedness efforts.
In the United States
- CDC works closely with state, tribal, local, and territorial public health departments to provide recommendations for clinical management, diagnosis, and prevention of monkeypox cases in the U.S.
- CDC continually increases capacity in communities across the United States for early detection of monkeypox through existing surveillance systems, including wastewater testing.
- CDC raises awareness for healthcare providers, including the latest guidance for diagnosing monkeypox and clinical decision-making.
- CDC has information and recommendations for members of the public, including travelers: Destinations | Travelers' Health, Travel Health Notices, and Health Alert Network advisories.
- CDC continues to work with international partners to help reduce monkeypox transmission.
Resources
- Get monkeypox and other vaccine recommendations when traveling to areas with monkeypox outbreaks: Destinations | Travelers' Health | CDC
- Monkeypox Virus Surveillance — United States, 2024–2025 | MMWR
- U.S. Monkeypox Wastewater Data | National Wastewater Surveillance System | CDC
- Health Alert Network (HAN) - 00519 | First Case of Clade I Monkeypox Diagnosed in the United States
- Health Alert Network (HAN) - 00516 | Prevention Strategies for Monkeypox, including Vaccinating People at Risk via Sexual Exposure, for U.S. Travelers Visiting Countries with Clade I Monkeypox Outbreaks
- The CDC Domestic Monkeypox Response — United States, 2022–2023
- U.S. Preparedness and Response to Increasing Clade I Monkeypox Cases in the Democratic Republic of the Congo — United States, 2024
- Notes from the Field: Clade II Monkeypox Surveillance Update — United States, October 2023–April 2024
- Early Release - The Rise of Monkeypox in a Post-Smallpox World - Volume 31, Number 1—January 2025 - Emerging Infectious Diseases journal - CDC
Content Source
National Center for Emerging and Zoonotic Infectious Diseases (NCEZID)
About This Page
Published: September 16, 2024
Updated: September 25, 2026
This page was last updated on this date. Updates may include minor edits, image changes, or other modifications to page content.
Reviewed: September 25, 2026
The information on this page was last reviewed by subject matter experts to ensure accuracy.