WHO declares mpox a global health emergency

It’s a deadly cousin of smallpox. It wasn’t even known before 1958. Now mpox—formerly known as monkeypox—is a global health emergency spreading through central Africa, including in countries where it has never been spotted before.

“The current upsurge of mpox in parts of Africa, along with the spread of a new sexually transmissible strain of the monkeypox virus, is an emergency, not only for Africa, but for the entire globe,” said World Health Organization committee chair Dimie Ogoina in a statement. “Mpox, originating in Africa, was neglected there, and later caused a global outbreak in 2022. It is time to act decisively to prevent history from repeating itself.”

The Democratic Republic of the Congo is experiencing the highest number of suspected mpox cases it has ever recorded in a year, with more than 15,600 cases and 537 deaths. Concerningly, mpox has also spread to neighboring countries where the disease has never been seen before including Burundi, Kenya, Rwanda, and Uganda. In response, the World Health Organization has declared a Public Health Emergency of International Concern.

But what exactly is mpox—and why does these outbreaks have experts more concerned than other recent outbreaks? Here’s what to know. 

What is mpox—and is it deadly?

Mpox, which until recently was known as monkeypox, is a much less severe, less contagious cousin of smallpox. Both are orthopoxviruses, a genus of 12 DNA viruses that also includes cowpox and camelpox. According to the WHO, it is marked by a painful rash, enlarged lymph nodes, and fever.

There are two distinct genetic clades, or varieties, explained Bernard Moss, a virologist at the U.S. National Institute of Allergy and Infectious Diseases (NIAID), in a 2022 interview. Clade I— the cause of the current outbreak —kills one in 10 of those infected. Clade II—the cause of the 2022 outbreaks—is far less deadly with a mortality rate of less than one percent.

A new version of the clade I virus, called clade Ib, has emerged in the current outbreak and motivated the emergency declaration, since it may be more severe or transmissible. Children also appear especially vulnerable, as many of the cases and deaths in the Democratic Republic of the Congo have been in those under 15 years old.

Mpox is a zoonotic disease, transmitted to humans by animals. First discovered in 1958 among monkeys in a Danish research lab, the virus’s original name may or may not be a misnomer. Small mammals are thought to harbor the virus in African rainforests where it’s endemic, but it can infect many mammals and has only been isolated in wild animals twice: a rope squirrel in the DRC in 1985 and a mangabey in Cote d’Ivoire in 2012. The actual disease reservoir(s) remain unknown.

(What are zoonotic diseases and where do they come from?)

Since the first known human case in 1970—when an infant boy was diagnosed in DRC—most infections have occurred in West and Central Africa. Early on, most were “spillover events,” contracted from hunting and butchering infected wild animals, Rosamund Lewis, who serves as the mpox technical lead at the WHO, told National Geographic in 2022.

How does mpox spread?

Both types of mpox can spread through direct contact with infected animals and contaminated materials. This can include items like clothing, bedding, and towels.

Close contact can also spread the virus between people—including by kissing, respiratory droplets that spread through talking to someone who has been infected, and direct contact with infectious skin or lesions on the mouth or genitals.

The lesions are contagious “little viral factories,” said Andrea McCollum, an epidemiologist with the U.S. Centers for Disease Control and Prevention. The incubation period is three to 17 days and, according to the CDC, people who have mpox symptoms are contagious “until the rash has fully healed and a fresh layer of skin has formed.”

(Are pets in danger from monkeypox?)

But until recently, the virus rarely spread beyond a few households within a community. Though this disease was characterized at least 52 years ago, “we actually don’t know nearly as much as we would like to,” said Lewis.

Is it a sexually transmitted disease?

The 2022 mpox outbreak overwhelmingly affected men who have sex with men. For public health officials, it’s been challenging to educate the public without stigmatizing that community.

The outbreak was likely amplified by sexual behavior at raves in Spain and Belgium, David Heymann, a longtime WHO infectious disease expert, told the Associated Press at the time. Those events seeded international spread, much like large gatherings disseminated COVID-19 during the early days of the pandemic.

But evidence suggests that mpox is not an STD, said Moss. When someone is symptomatic, it’s spread skin-to-skin—including through sexual behaviors—and can also be transmitted through contact with bedsheets, towels, or clothing.

Previous outbreaks in Africa have infected women, children, and men of all ages. “There are no guardrails. This virus is not necessarily going to stay within one gender or one population,” warned Anne Rimoin, an infectious disease epidemiologist and professor at the University of California Los Angeles School of Public Health. 

Public education is key. “We don’t want people to worry, but awareness is what you need to protect yourself,” Lewis adds. “What we need is for each person to know their own risk…and manage it.”

Are there tests and vaccines available?

There are existing tests for mpox, which involve simply swabbing a lesion. The CDC recommends testing only if you have an mpox-like rash.

There are two vaccines currently in use for mpox, both recommended by WHO’s Strategic Advisory Group of Experts on Immunization. The U.S. Department of Health and Human Services encourages people who are at high risk to get a vaccine—and to be sure to get both doses of the two-dose Jynneos vaccine.

The good news is that people who are already full vaccinated or who previously had clade II mpox “are expected to be protected against severe illness from clade I mpox.”

However, the Associated Press reports that the vaccines are not widely available in African countries most vulnerable to outbreaks. The WHO’s declaration of a Public Health Emergency of International Concern legally allows the agency to make recommendations on how member countries should handle an epidemic. It also mobilizes funding and political support.