Why mpox is a global health emergency — again

For the second time, the World Health Organization has declared that mpox, formerly called monkeypox, is a global health emergency.

In 2022, global spread of the virus, which causes rashes, fevers, muscle aches and other symptoms, led to the first emergency declaration (SN: 7/22/22). That version of the virus, called clade II, is still causing a small number of cases around the world, including in the United States.

Even as clade II cases declined globally, infections with clade I mpox shot up in Congo. Nevertheless, the first mpox emergency ended in 2023. The sometimes deadly clade I virus has now spread to previously unaffected countries in Africa and reported cases have surged beyond levels seen in 2022 or 2023. Children have been particularly hard hit.

On August 13, the Africa Centres for Disease Control and Prevention said that the ongoing mpox outbreak is a public health emergency of continental security, a first for  the organization. On August 14, a WHO panel of experts found ample evidence that mpox is again a global emergency, said Dimie Ogoina, an infectious disease physician at the Niger Delta University Teaching Hospital in Okolobiri, Nigeria, and chair of the emergency committee.

Following the committee’s advice, WHO Director-General Tedros Adhanom Ghebreyesus said August 14 that the outbreak is now a public health emergency of international concern. “It’s clear that a coordinated international response is needed to stop these outbreaks and save lives,” he said.

Sweden reported a case of mpox linked to travel to Africa, the country’s Public Health Agency announced August 15. The person was infected with  clade I mpox, the first time that version of the virus has been diagnosed outside the African continent.

Here are three things to know about the outbreak.

Why is mpox an emergency again?

The disease has spread rapidly in Africa, now affecting people in at least 13 countries, the Africa CDC says. Congo, which has had a steady rise in cases over the past decade, has seen big increases last year and this year. Across Africa this year alone, there have been more than 15,600 cases and 537 deaths from mpox, including deaths of young children and people whose immune systems were weakened by HIV.

About 90 cases of the disease have popped up in countries such as Burundi, Kenya, Rwanda and Uganda that had never before recorded mpox cases. 

To make matters worse, a new version of the virus, known as clade Ib, emerged in Congo and has now been confirmed in four neighboring countries. That variant appears to cause more severe cases and may be more transmissible than clade II, which caused the 2022 outbreak.

The 2022 outbreak affected mostly men who have sex with men, though the virus also spread to others through contact with skin or infected clothing, bedding or other objects.

Clade Ib is spreading among adults through heterosexual sex, which may become a problem particularly for pregnant women, Ogoina said during a news conference: An infection could put them and their babies at risk.

And this time around, children have proven to be particularly vulnerable to the virus. As of May 26, two-thirds of the cases reported this year in Congo, or 5,254, have been in children age 15 and younger. And 87 percent of the deaths, or 321, have been among that age group.  

In Burundi and Congo, there is evidence that the virus is spreading in the community, while the other countries have so far reported isolated cases.

What is the significance of calling mpox a public health emergency?

Vaccines and treatments will be deployed to help protect vulnerable people in some countries. Supplies of both are limited and experts warn that the full scope of the outbreak is not known. Increasing surveillance will be important to understand how the disease is spreading and who would benefit most from vaccination, WHO epidemiologist Maria Van Kerkhove said during the news conference.

WHO is asking for $15 million from the global health agency’s emergency fund to pay for increased surveillance and countermeasures. WHO is also asking other countries to donate vaccines from their national stockpiles. Japan has already stepped forward to offer up its own version of the mpox vaccine.

Congo and Nigeria have promises that they may be able to get enough vaccine this fall to deploy, but other African countries are still waiting.

The 2022 mpox outbreak showed that getting the word out to affected communities and talking with them about ways to stay safe are also effective at containing an outbreak, Van Kerkhove said. “There are a lot of interventions that can be utilized in country, in communities, to prevent transmission.”

Can the outbreak be stopped?

Maybe, but it will take effort.

Scientists don’t fully understand many things about the virus, including which animals serve as a reservoir for it and whether there is a real difference in the severity and transmissibility between the two clades circulating now.

One thing is clear. The world can’t afford to ignore the virus’ spread in Africa any longer, Ogoina said. “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.”