An infectious viral disease that can cause symptoms in humans such as a rash that forms blisters and then crusts over, fever, or swollen lymph nodes, mpox is usually mild but it’s causing concern among health experts.
The disease is caused by a zoonotic virus in the genus Orthopoxvirus, the same genus as variola virus, which causes smallpox.
Since January 1, 2024, the Democratic Republic of the Congo (DRC) has reported more than 33,000 suspect mpox cases and more than 1,000 deaths.
Of these, about 6,700 cases have been confirmed through laboratory testing.
There are two types of mpox, clade I and clade II. Clade I has historically caused a higher number of people with mpox to get severely sick or die compared to clade II.
The virus that causes clade I mpox occurs regularly, or is endemic, in DRC.
The current outbreak is more widespread than any previous DRC outbreak, and clade I mpox has spread to some neighboring countries, including Burundi, Central African Republic, Republic of the Congo, Rwanda, and Uganda.
There have also been travel-associated cases in Germany, India, Kenya, Sweden, and Thailand.
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.
The declaration focuses international attention on acute public health risks that require coordinated mobilization of extraordinary resources by the international community for prevention and response.
The American government’s response to the outbreaks in several African countries is intended to prevent the disease from landing on our shores, but no cases of clade I mpox have been reported in the United States at this time.
CDC assessed the risk to the United States posed by the clade I mpox outbreak in the Democratic Republic of Congo and neighboring countries.
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.
Health experts warn the risk assessment might change as more information becomes available.
Mpox needs close or intimate contact to spread, so it’s not spread through casual contact, such as one might have in public spaces like markets, offices, classrooms, or during travel.
The best protection against mpox is two doses of the JYNNEOS vaccine if you’re eligible.
People can also protect themselves by:
- Avoiding close contact with people who are sick with signs and symptoms of mpox, including those with skin lesions or genital lesions.
- Avoiding contact with wild animals (alive or dead) in areas where mpox regularly occurs.
- Avoiding contact with contaminated materials used by people who are sick with mpox (such as clothing, bedding, or materials used in healthcare settings) or that came into contact with wild animals.
- Avoiding eating or preparing meat from wild animals (bushmeat) or using products (creams, lotions, powders) derived from wild animals.
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.
Travelers have contracted mpox and brought it to Sweden, Thailand, Germany, and India.
Given the widespread clade I outbreak in Central and Eastern Africa, rapid detection and stopping any potential spread of mpox is considered key to stopping a global outbreak.