Spread of Deadlier Mpox Strain in Africa Has CDC Concerned

May 16, 2024
Ernie Mundell HealthDay Reporter

The central African nation of the Democratic Republic of Congo (DRC) is battling a record number of cases of mpox, fueled by a strain with a higher death rate than the variant that spread in Europe and America in 2022.

Getting the DRC outbreak under control, and containing it to within that country, is imperative, experts at the U.S. Centers for Disease Control and Prevention said in a report issued Thursday.

The spread of the lethal clade I strain of mpox "raises concerns that the virus could spread to other countries and underscores the importance of coordinated, urgent global action to support DRC's efforts to contain the virus," said a team led by CDC research biologist Christina Hutson.

The strain of mpox (formerly known as monkeypox) that spread from Africa to Europe and North America two years ago was known as clade II.

While painful and sometimes severe, the illness resulted in a death rate ranging from 0.1% to 3.6% of cases, according to various studies.

But clade 1 mpox is more lethal, and deaths from the illness have ranged anywhere from 1.4% to 10% of patients, Hutson's team noted.

The ongoing outbreak of clade I mpox in the DRC has already claimed many victims: The DRC reports "multiple provincial outbreaks" occurring between the beginning of 2023 and April 14, 2024, with an estimated total of 19,919 cases and 975 deaths -- meaning that about 1 in every 20 patients have died.

This outbreak is also perhaps the most widespread: "During 2023 and 2024, clade I mpox cases were reported from 25 of 26 provinces and, for the first time, from the capital city of Kinshasa," the CDC team noted.

Children are especially vulnerable: According to the report, "two thirds (67%) of suspected cases and more than three quarters (78%) of suspected deaths have occurred in persons aged 15 years [or younger]."

Mpox is spread through close personal contact. This typically involves skin-to-skin contact, so sex can often be a means of transmission. Initial symptoms include fever, chills, exhaustion, headache and muscle weakness, often followed by a rash with lesions that scab over and slowly heal over a period of weeks.

Although anyone can get mpox, men who have sex with men are particularly at risk, and those who have HIV are more vulnerable to severe disease.

"In two outbreaks [in the DRC], sexual transmission of clade I MPXV was reported among men-who-have-sex-with-men and both male and female sex workers and their contacts," the researchers said.

Mpox has long been endemic to Africa, since it can be spread to humans via contact with animals such as monkeys. In the recent DRC outbreak, the data "suggests that outbreaks involve multiple introductions from animal hosts within DRC," Hutson's team said.

Luckily, there is an mpox vaccine, manufactured under the brand name Jynneos. It's a two-dose regimen, with shots given about a month apart.

The CDC team said that the agency has long been working in the DRC, helping that country battle mpox outbreaks.

"CDC's support for DRC's mpox-related activities during the last 15 years has included establishing laboratory testing and training, supporting diagnostic testing and genetic sequencing, conducting Jynneos vaccine clinical research, and training frontline health care workers," Hutson's team said.

Regarding the latest outbreak, the CDC is working both in the DRC (and surrounding countries) to help contain the virus, while bolstering preparedness in the United States should clade I emerge among Americans.

"CDC issued a Health Alert Network notice on December 7, 2023, urging U.S. clinicians to consider clade I MPXV infection in persons with mpox signs and symptoms who had recently been in DRC," the study authors said. "The notice recommended expedited clade-specific testing for those patients."

They stressed that "to date, no cases of clade I mpox have been reported in the United States or in any countries where the virus is not endemic."

The researchers also stressed that the risk of mpox clade 1 affecting children in the United States is much less likely.

That's because animals in the United States do not harbor mpox, families tend to live in less crowded quarters, and typical household hygiene is markedly better than that of many low-income families living in the DRC.

Still, the risk to Americans -- especially high-risk groups such as gay and bisexual men -- is very real should clade I emerge in this country, the team noted.

Vaccinating at-risk individuals is imperative, but "in the United States, only 23% of persons at risk for clade II MPXV infection have completed the 2-dose Jynneos vaccination series," the CDC team noted.

Already, there are "reports of increased mpox in some [DRC-] bordering countries," the researchers noted, heightening fears of another, more deadly global outbreak.

Therefore, "U.S. clinicians and public health practitioners should be alert for possible cases in travelers from DRC and request clade-specific testing," Hutson's team concluded.

"Appropriate medical treatment is critical given the potential for severe illness, and contact tracing and containment strategies, including isolation, behavior modification and vaccination, will be important to prevent spread if any U.S. clade I mpox cases occur," Hutson's team said.

The findings were published May 16 in the CDC journal Morbidity and Mortality Weekly Report.

More information:

Find out more about mpox at the World Health Organization.

SOURCE: Morbidity and Mortality Weekly Report, May 16, 2024

Sexually Transmitted Diseases: Misc.