In May 2023, the World Health Organization released a statement announcing the end of mpox, previously known as monkeypox—as a public health emergency. Just over a year later, the agency has been forced to back down, with a much more serious epidemic brewing across much of sub-Saharan Africa.
Statistics show that since January, more than 15,000 cases of mpox and 461 deaths have been reported on the African continent. The disease has spread from countries such as the Democratic Republic of Congo (DRC), where mpox has long been endemic, to 13 other African countries: countries such as Rwanda, Kenya, Burundi and Uganda, where the disease has never struck before.
Scientists like Boghuma Titanji, an associate professor of infectious diseases at Emory University who studies MPOX outbreaks, say this new, deadlier outbreak is a result of global health watchdogs not doing enough last time.
It was the summer of 2022 when the distribution of mpox first alarm bells are ringing. Suddenly, a virus that had been contained mainly in parts of West and Central Africa suddenly spread worldwide. Between early 2022 and December 2023, there were 92,783 confirmed cases of mpox in 116 countries, resulting in 171 deaths.
Despite these numbers, its perception as a public health threat quickly faded. “Ninety-five percent of cases in the 2022 outbreak were among men who have sex with men and who reported exposure through sexual or close contact with another infected person,” Titanji says. “It was a very targeted outbreak, which allowed vaccinations to be prioritized within that network.”
Countries in the Global North have successfully tried to suppress the outbreak within their own borders. Meanwhile, Titanji says, ramping up viral surveillance among African countries that have been battling a steady rise in MPOX cases over the past four decades quickly faded into the background, allowing a potentially more problematic variant to emerge undetected.
Mpox comes in two main subtypes, clade 1 and clade 2. Clade 1 is thought to be up to 10 times more deadly, particularly among populations with weakened or developing immune systems, such as children under 5, pregnant women and people with compromised immune systems. That’s the strain behind this new outbreak and what has infectious disease scientists so alarmed. (A separate outbreak spreading among people living with HIV in South Africa is thought to be linked to clade 2.)
“The 2022 global outbreak was clade 2, and the mortality was less than 1 percent,” says Jean Nachega, a Congolese infectious disease physician and associate professor of medicine at the University of Pittsburgh. “Now we're talking about a strain that is up to 10 percent mortality.”
While the previous outbreak primarily affected homosexual populations, data indicate that the new strain is also being transmitted much more broadly, perhaps first through sexual networks and then passed on to family members. Last month, Nachega and others published a paper in the diary Nature Medicine shows how an outbreak of mpox started in the small mining town of Kamituga in the eastern Democratic Republic of Congo through sex workers, and then spread to nearby Rwanda, Uganda and Burundi as infected individuals returned home to visit their families.