The World Health Organization (WHO) has once again designated mpox as a global public health emergency, the second such declaration in two years. This follows a surge of the viral infection in the Democratic Republic of Congo (DRC), which has since spread to nearby African nations.
A “public health emergency of international concern” (PHEIC) is the highest alert level issued by the WHO, aimed at promoting swift research, funding, and collaborative international health measures to contain the outbreak.
Earlier this week, Africa’s primary public health organization declared mpox, previously known as monkeypox, an emergency as the viral infection is escalating alarmingly across the continent. The Africa Centers for Disease Control and Prevention reported over 17,000 suspected cases and 517 deaths this year, marking a 160% rise compared to last year, with cases reported in 13 countries.
Mpox consists of two viral clades, I and II, both capable of spreading through close contact with infected individuals or through direct interaction with infected animals or contaminated surfaces. The current outbreak in Congo involves clade I, a strain endemic to central Africa that is characterized by higher transmissibility and more severe infections, with past outbreaks resulting in a mortality rate of up to 10%.
A new variant of clade I, known as clade Ib, is now spreading and is thought to be more easily transmitted through routine close contact, including sexual activity. This variant has extended from the DRC to neighboring nations such as Burundi, Kenya, Rwanda, and Uganda, prompting the WHO’s intervention.
WHO Director-General Tedros Adhanom Ghebreyesus emphasized the necessity of an organized international response to halt these outbreaks and protect lives.
A different strain, clade II, was responsible for the global spread of mpox in 2022, leading the WHO to declare a public health emergency. Although infections from clade II are generally less severe—with over 99.9% survival rate—there are still risks, particularly for individuals with weakened immune systems. This variant primarily spread through sexual contact among men who have sex with men and was classified as clade IIb.
The WHO lifted the emergency declaration 10 months later. In the United States, mpox cases have significantly decreased since their peak in 2022, with average daily cases dropping to zero by the beginning of August.
However, due to the ongoing virus spread in the DRC and its neighboring countries, the CDC advised doctors to remain vigilant for mpox symptoms in individuals who have recently been in the area. Currently, clade I cases have not been reported outside of central and eastern Africa, but the CDC highlighted the risk of further transmission.
Enhanced precautions have been recommended for travelers to the DRC and surrounding countries, urging them to seek prompt medical attention if they develop any skin rash. The U.S. Department of Health and Human Services has stated that the country is prepared to identify and handle potential cases of clade I, as health officials monitor mpox through clinical testing and wastewater surveillance.
Should clade I be detected in the U.S., the HHS expects it would result in lower morbidity and mortality compared to the DRC.
Mpox typically manifests with a rash resembling chickenpox, syphilis, or herpes, which evolves into bumps, then blisters filled with a whitish fluid. Accompanying symptoms may include fever, headache, muscle aches, back pain, fatigue, and swollen lymph nodes.
A vaccine for mpox is accessible in the U.S. but is not widely available in the DRC. The U.S. plans to donate 50,000 vaccine doses to help address this shortage. The CDC advises individuals at higher risk of infection—such as men who have sex with men—to receive two doses of the vaccine, which is effective against both clades of mpox.