WEDNESDAY, Aug. 21, 2024 (HealthDay News) -- The first mpox vaccine doses from the United States are set to arrive next week in the Congo, the epicenter of an ongoing mpox outbreak in Africa.

The doses come not a moment too soon: Just last week, the World Health Organization declared the outbreak a global health emergency. As officials struggle to contain a strain of the virus that appears to be more contagious and more severe, vaccines are in short supply.

So far, the Congo has reported the vast majority of mpox cases and needs 3 million vaccine doses to make a dent in the spread of the virus.

Both the United States and Japan have offered to donate vaccines, Congo Health Minister Roger Kamba told journalists on Monday, the Associated Press reported. However, he didn't say exactly how many doses would be sent or exactly when the ones from Japan would arrive.

The vaccines are sorely needed: According to the Africa Centers for Disease Control and Prevention, the new outbreak has led to more than 17,500 confirmed and presumed mpox cases and 524 deaths in 13 countries, some of which have never been affected by the disease before.

Most cases have occurred in the Congo, and women and children under the age of 15 appear to be most at risk.

The newly spotted strain did surface outside of Africa for the first time last week, when Sweden reported a case of mpox in a person who had traveled to the Congo.

Meanwhile, the U.S. Centers for Disease Control and Prevention issued an alert earlier this month that advised health care providers to be on the lookout for the new mpox strain in patients who have recently been in the Congo or any neighboring country (Angola, Burundi, Central Africa).

Still, "due to the limited number of travelers and lack of direct commercial flights from [Congo] or its neighboring countries to the United States, the risk of clade I mpox importation to the United States is considered to be very low," the CDC added.

The WHO declaration was meant to spur health agencies in countries worldwide to be on heightened alert for local cases, and to help supply vaccines, treatments and other resources to developing nations hit hard by the disease.

“We need concerted international action to stem this recent, novel outbreak,” Gregg Gonsalves, an epidemiologist at Yale University who served on the WHO’s mpox committee in 2022, told the New York Times.

It's the second time in three years the WHO has designated an mpox outbreak a global health emergency.

In July 2022, an outbreak that originated in Africa spread worldwide, affecting nearly 100,000 people, primarily gay and bisexual men, across 116 countries and killing about 200 people, the Times reported.

What's worrying in the new outbreak is that the death rate linked to the new strain of the disease appears higher: About 3 percent of those infected have died, instead of the 0.2 percent observed in the 2022 outbreak.

Mpox is spread by close skin-to-skin contact, including sex. It's characterized by a painful rash on hands, feet, chest, mouth or genitals, as well as fever, respiratory symptoms, muscle aches and swollen lymph nodes.

There is a vaccine, Jynneos, that can shield at-risk people from mpox.

Vaccination plus behavioral change among gay and bisexual men, the group most affected in the United States in the 2022 outbreak, has caused U.S. cases of mpox to fall from more than 30,000 in 2022 to 1,700 in 2023.

But the virus is changing: Scientists discovered in 2023 that mpox has gained mutations allowing it to spread more easily between people. Sexual transmission, often through heterosexual prostitution, is a main conduit for infection in Africa.

“I think we learned a great deal about the speed with which this virus can spread,” Anne Rimoin, an epidemiologist at the University of California, Los Angeles, told the Times. She also served on the 2022 mpox panel.

Donated vaccines are trickling in to Africa, but the Africa CDC has said that over 10 million doses will be needed to rein in the outbreak.

Dr. Nicole Lurie is executive director for preparedness and response at the Coalition for Epidemic Preparedness Innovations, a nonprofit that finances vaccine development.

Speaking to the Times, she said, “this outbreak has been smoldering for quite a long time, and we continually have missed opportunities to shut it down. I’m really glad that everybody is now paying attention and focusing their efforts on this.”

More information

Find out more about mpox at the U.S. Centers for Disease Control and Prevention.

SOURCE: Associated Press; WHO, news release, Aug. 14, 2024; New York Times