Eduardo Cuevas, USA TODAY
A highly contagious and severe strain of mpox is crossing continents and U.S. officials are preparing for its eventual arrival here.
U.S. officials are pleading with the public to take precautions now that mpox has been declared a global public health emergency after the first case was identified outside of Africa.
On Thursday, Swedish officials said they recorded their first case of mpox, which spreads with skin contact. The announcement came a day after the World Health Organization issued its second emergency declaration in two years due to the recent outbreak in and around the Democratic Republic of Congo, in central Africa.
The mpox virus circulating in Congo and a dozen other African countries, and now Sweden, is a different strain than the one that has circulated in the U.S. since a global outbreak began in 2022. In the U.S., the virus, known as mpox clade II, has primarily circulated among men who have sex with men. On Friday, Pakistan health officials said a person who had returned from a Gulf country contracted mpox, though it was unclear which virus strain the person had.
The latest outbreak of mpox clade I began in Congo, affecting a region that already has experienced several destabilizing conflicts. Mpox clade I is considered more transmissible and the symptoms are more severe. It has infected tens of thousands of people, including children, sex workers and workers in health care settings who lack proper protective equipment.
The U.S. said it would donate 50,000 vaccine doses to Congo. However, experts predict that millions more will be needed from Western countries, particularly the U.S., to help stop the virus. To make this happen, vaccine manufacturers will have to increase production dramatically.
“It’s really just a very small down payment on what’s needed to really contain this outbreak and prevent it from spreading across Africa and potentially across Europe and the United States,” Lawrence Gostin, director of the O’Neill Institute for National and Global Health Law at Georgetown University, told USA TODAY before Sweden’s announcement.
What is mpox?
Mpox, previously known as monkeypox, is a virus that spreads to people from animals and was named monkeypox because that’s the animal it was first discovered in, not because monkeys are the source of infections. It comes from the same virus family as smallpox and can pass from person to person through physical contact, according to the Centers for Disease Control and Prevention.
It was first discovered in 1958 and the first human case occurred in 1970 in Congo. Infection is usually mild, but it can result in death. It causes symptoms similar to flu, as well as pus-filled skin lesions.
There are two types of mpox – clade I and clade II. Clade I is endemic in central Africa, while clade II is endemic in West Africa. A new variant of clade I, called Ib, appears to spread more easily.
Congo and surrounding countries have had worsening outbreaks since 2023. Just in 2024, central and eastern Africa have had over 17,000 infections and more than 500 people died from mpox, primarily in Congo, according to the Africa Centres for Disease Control and Prevention, which recently issued its own emergency declaration for the outbreaks.
On Thursday, David Daigle, a CDC spokesperson, said the traveler in Sweden identified with the disease had visited an affected African country. This was the first case of the new strain to be documented outside the African continent. The patient sought medical care and is being treated, Daigle said in an email.
“Given how widespread the clade I outbreak is in central and eastern Africa, a case diagnosed in an occasional traveler is not unexpected,” he said. “Rapid detection and containment of any mpox case are key to stopping mpox spread.”
How prevalent is mpox in the U.S.?
There were no reported cases of clade I mpox in the U.S. as of Thursday. Federal officials say the risk is low, and Daigle said the CDC is monitoring the European case. A few cases of the less severe strain of the virus are still reported each week in the U.S.
The CDC issued a health alert and travel notice about the stronger mpox strain in Congo and neighboring countries, recommending providers and health agencies monitor for signs and ask patients about recent travel to affected areas.
Since 2022, the U.S. has had outbreaks of clade II mpox, mostly among men who have sex with men, but also in some nonbinary and transgender people, according to recent CDC data. Overall, more than 32,000 people in the U.S. have been infected and 58 have died of mpox.
Most of the early U.S. cases two years ago were in New York City.
On Thursday, Ashwin Vasan, New York City Health Commissioner, urged the country to act quickly to halt the spread of clade I, noting that “uncertainties cannot delay preparation, and the moment to act is now.”
“As we learn time and again, we are connected, and we cannot stand by and hope that another country’s suffering will not reach us,” Vasan said in a statement. “Prevention means we must be as invested in each other as we are in ourselves. It is not only moral and ethical, but also strategic.”
Should I get a vaccine?
Vaccines are available and recommended for people from higher-risk populations. The approved JYNNEOS vaccine, a two-dose series administered at least four weeks apart, provides protection against both clade I and clade II.
Since August 2022, the federal Administration for Strategic Preparedness and Response has procured and distributed over 1 million vials of the JYNNEOS vaccine across the U.S., agency spokesperson Spencer Pretecrum said in an email.
But more than 75% of at-risk populations in the U.S. have not been fully vaccinated against mpox, a CDC analysis found. Many people who get their first shot of the mpox vaccine do not return for their second dose. Some estimates say just a quarter of people who got an initial dose came back for a second dose. Full protection against the virus requires both doses.
The vaccine is highly effective, a recent CDC report showed. Fully vaccinated people became infected in less than 1% of cases. And for those who did, infections were milder compared to unvaccinated people.
Federal officials recommend this vaccine for people 18 and older who fall into these categories:
- Gay men; bisexual men; men who have sex with men; and transgender and nonbinary people. People in these categories are at risk if they’ve had at least one new diagnosis of a sexually transmitted infection in the past six months; they have more than one sex partner; they have had sex at a commercial sex venue or at a large public event where mpox transmission was occurring.
- Sexual partners of people in the previous category, or people who plan to have those sexual experiences.
What about boosters?
If you’ve had the two-dose series, boosters are not recommended, the CDC said. Dr. Trish Perl, a professor of infectious diseases and geographic medicine at the University of Texas Southwestern Medical Center, in Dallas, said the mpox vaccine provides prolonged immune protection.
Mpox is related to smallpox, a disease that’s been eradicated worldwide since 1980, and vaccines once used against smallpox have been effective over the years, Perl said.
Vaccines against smallpox provided lifelong protection, but it’s too soon to know if Jynneos’ protection will be as long-lived, she said.
How is the U.S. responding to the global spread?
Experts say vaccination will be key in the U.S., but it is also vital for communities to amp up surveillance for mpox cases.
Surveillance is public health’s “eyes and ears,” Perl told USA TODAY. Then, if more disease is found circulating, public health officials can escalate responses to reduce the risk of spread, she said.
Experts also stressed the importance of educating the public about risks and prevention. Scott Bertani, from the National Coalition for LGBTQ Health, which has an mpox resource center, said addressing the virus requires a “status neutral approach” with health care. That means promoting healthy activities to prevent HIV, STIs and mpox and encouraging regular access to care.
“It is truly a critical time in our community’s summer to take the opportunity to have conversations with each other about our health,” he told USA TODAY. “So that we avoid complacency, so that we don’t turn a blind eye to things that are affecting our community.”
