Enlarge / A 2003 photo of the arms and legs of a 4-year-old girl infected with mpox in Liberia.

A deadly outbreak of mpox (previously called monkeypox) is spilling out of the Democratic Republic of the Congo, raising alarm among global health experts.
The DRC has reported more than 22,000 suspected cases since the start of 2023, including 1,200 suspected deaths, according to the US Centers for Disease Control and Prevention. A high proportion of the cases are in children younger than 15 years old.
On Wednesday, the CDC released a health advisory noting that although mpox is endemic to the DRC, the current outbreak is larger and more widespread than any outbreak the country has previously seen. The virus has also spilled over to several neighboring countries in recent months, including the Republic of the Congo, the Central African Republic, Burundi, Rwanda, and Uganda. The World Health Organization reported that cases have also been detected in Kenya.
Also on Wednesday, WHO Director-General Tedros Adhanom Ghebreyesus announced that he would convene an emergency committee as soon as possible to assess if the outbreak constitutes a public health emergency of international concern (PHEIC), the agency’s highest level of alert.
Unlike the 2022–2023 international outbreak of mpox—which WHO declared a PHEIC in July 2022—the current outbreak is caused by a different clade of mpox; the previous outbreak was caused by clade II of the virus, while the current outbreak is caused by clade I, which causes more severe illnesses and death.

According to the CDC, symptoms of mpox include a rash that may be located on the hands, feet, chest, face, mouth, or near the genitals; fever; chills; swollen lymph nodes; fatigue; myalgia (muscle aches and backache); headache; and respiratory symptoms like sore throat, nasal congestion, and cough.
In the current outbreak, the spread seems to be occurring through well-known transmission routes, including contact with live or dead wild animals that carry the virus, household contact, and patient care. But, there’s also evidence of spread through sexual contact, which is a first for clade I mpox.
For now, the CDC considers the risk to the US to be “very low,” given that there are no direct flights between the US and the DRC or its neighboring countries. No cases of clade I mpox have been reported outside of central and eastern Africa so far. Still, in today’s advisory, the CDC advised clinicians to consider mpox in patients with related symptoms who had traveled to the DRC or a nearby country in the past 21 days.
The mpox vaccines used in the previous outbreak are expected to be effective against both clades of the virus. In a separate announcement Wednesday, the US Agency for International Development (USAID) announced that it would provide $10 million to help the DRC respond to the outbreak as well as 50,000 doses of mpox vaccine.