The virus mpox, formerly known as monkeypox, has been making the rounds again, and this time, it’s more deadly.
A version of the virus has been spreading in the Democratic Republic of Congo for decades, where it is endemic, but this summer it ballooned into a full-scale outbreak and breached the African country’s eastern border, reaching Burundi, Uganda and Rwanda. Then in August, two separate travelers from Sweden and Thailand tested positive for the virus. On Monday, a case of the current strain was reported in India, per Reuters.
The currently circulating subtype of mpox has been disproportionately impacting children in the DRC. UNICEF reported that 56% of cases in the country were in kids under the age of 15, with more than 8,000 infected and hundreds dead as of mid-August counts.
Mpox is spread in many ways, from sharing linens, touching the characteristic red sores and inhaling the respiratory droplets of an infected person. Children and those who are pregnant, have HIV or are immunocompromised are at highest risk of the disease.
So is there a threat to the U.S.? The short answer is yes.
“Yes, there is a risk that this could become global,” said Jean Nachega, associate professor of epidemiology at the University of Pittsburgh School of Public Health and an mpox expert. “We saw it before, and there’s no reason not to see it again.”
WHO Director General Tedros Adhanom Ghebreyesus declared the outbreak a public health emergency of international concern on Aug. 14, even before it reached Sweden and Thailand.
The virus is circulating easily to neighboring countries of Africa, he said.
“When clade I entered Sweden, that was really a red flag for the World Health Organization.”
The version that’s spreading abroad is a subtype of mpox — which is in the smallpox family of viruses — called clade Ib. Just as SARS-CoV-2 has mutated over time into different subvariants, mpox has split into clades I and II, both with “a” and “b” subtypes.
Clade IIb is what was spreading in the U.S. in the summer of 2022. While it had a very low mortality rate of about 0.2%, it infected more than 100,000 people across 122 countries — 115 of which had never before seen mpox — according to the Centers for Disease Control and Prevention, and it killed 58 people in the U.S.
It’s important to remember that the spread of clade IIb hasn’t ended, said Amesh Adalja, a Pittsburgh-based infectious disease physician and senior scholar for the Johns Hopkins University Center for Health Security.
“The 2022 global clade II outbreak was almost exclusively tied to getting into sexual relationships with men who have sex with men,” he said. “That outbreak continues to simmer on.”
Per Allegheny County Health Department’s website, the 2022 outbreak the county saw 71 cases, and this year still more cases trickle on, with 10 in April, three in May, one in June, and two in both July and August.
“We continue to see a low number of clade II mpox cases in Allegheny County since cases were first reported in our county in 2022,” said Barbara Nightingale, deputy director for clinical services at ACHD, via email statement.
Since Sept. 19, there have not been any mpox cases reported for the month of September, and the county updates its website within a few days of receiving news of an additional infection, she said.
The threat of clade Ib spreading abroad is not a cause for alarm at this time, said Adalja — but Western countries shouldn’t believe it’s impossible, either.
“I don’t think this is a major threat to Western countries, although Western countries need to be prepared to receive the virus,” he said. “Clade Ib is pretty geographically constricted. There are no direct flights from the Democratic Republic of Congo into the U.S. But I would not be surprised if a case popped up in the U.S.”
Allegheny County Health Department is prepared for clade I anyway.
Nightingale said the ACHD Public Health Laboratory is in the process of validating a test for mpox; afterward it will be able to check for the presence of clade I virus in people who have traveled to clade I-endemic counties. And ACHD investigates each mpox-positive case in the county to learn about the virus, and to inform the person who has been diagnosed and their close contacts about next steps.
Jynneos, a vaccine created by Danish company Bavarian Nordic that has prevented smallpox transmission, was utilized in 2022 to control the spread of mpox, and it’s currently undergoing clinical trials to see how well it works to curb mpox clade I.
Adalja and Nachega said the Jynneos vaccine should be effective against clade I, and that experts will know more soon as results from the clinical trial roll out.
Right now, the plan is to limit clade Ib mpox transmission and severe disease while it’s possible to do so, said Nachega.
“The effort is to try to limit the spread in DRC to prevent a global outbreak,” he said. “We are actively involved in the research of this virus, which has been long neglected. It’s been around for more than five decades, and there’s not much we know about it.”
The outbreak has strained resources and highlighted gaps in health equity, with DRC health systems at times unable to access the vaccine and protect its population. In response, multiple countries have pledged to donate Jynneos doses from their stockpiles, including the U.S. offering 50,000 doses, which the United States Agency for International Development said arrived in the DRC on Sept. 10.
Nachega is hoping to travel to the country himself to aid in research efforts. He is originally from the DRC and moved to Europe for medical school, and then to Johns Hopkins in 1999, where he completed a master’s degree in public health.
“I want to be there [in DRC] as a doctor,” he said. “It’s really heartbreaking when you see all these children affected with high mortality. I’m from the DRC, so this is close to my heart.”
First Published: September 28, 2024, 9:30 a.m.
Updated: September 30, 2024, 3:11 p.m.
