A highly contagious strain of mpox is spreading across continents, prompting U.S. officials to prepare for its inevitable arrival.

U.S. officials are urging the public to take precautions now that mpox has been labeled a global public health emergency following its first case being reported outside Africa.

On Thursday, officials in Sweden announced their first case of mpox, which is transmitted through skin contact. This news followed the World Health Organization’s second emergency declaration in two years, tied to the recent outbreak in and around the Democratic Republic of Congo in Central Africa.

The mpox virus affecting Congo and several other African nations, including Sweden, is a different strain than that which emerged in the U.S. during the global outbreak starting in 2022. In the U.S., the virus, identified as mpox clade II, has mainly affected men who have sex with men.

The mpox clade I outbreak, which began in Congo, is notable for occurring in a region already burdened by instability. This strain is deemed more contagious and tends to exhibit more severe symptoms. It has impacted tens of thousands of individuals, including children, sex workers, and healthcare workers without sufficient protective gear.

The U.S. has pledged to send 50,000 vaccine doses to Congo, yet experts caution that millions more doses from Western nations, especially the U.S., are crucial to curbing the virus’s spread. Vaccine manufacturers must dramatically ramp up production to meet this demand.

“This is just a small initial step towards what’s necessary to effectively contain this outbreak and prevent its spread throughout Africa and possibly to Europe and the U.S.,” stated Lawrence Gostin, director of the O’Neill Institute for National and Global Health Law at Georgetown University, before Sweden made their announcement.

What is Mpox?

Mpox, which was previously referred to as monkeypox, is a virus that is transmitted from animals to humans. The name monkeypox comes from the fact that it was first detected in monkeys, not because they are the primary carriers of the infection. Mpox belongs to the same family of viruses as smallpox and can be spread from person to person through direct contact, per the Centers for Disease Control and Prevention.

Initially identified in 1958, the first human case was recorded in 1970 in Congo. While most infections are mild, severe cases can occur, leading to fatalities. Infected individuals often experience flu-like symptoms along with painful skin lesions.

There are two main types of mpox: clade I and clade II. Clade I is mostly found in Central Africa, while clade II is prevalent in West Africa. A recently identified variation of clade I, known as Ib, appears to be more easily transmitted.

Since 2023, outbreaks have worsened in Congo and neighboring countries. In 2024 alone, Central and Eastern Africa has reported over 17,000 cases and more than 500 deaths from mpox, chiefly in Congo, according to data from the Africa Centres for Disease Control and Prevention, which has also issued an emergency declaration regarding these outbreaks.

On Thursday, David Daigle, a spokesperson for the CDC, reported that the traveler in Sweden diagnosed with mpox had recently visited an affected African nation. This marked the first documentation of the new strain outside Africa. The individual is currently receiving medical care, Daigle confirmed via email.

“Considering the widespread prevalence of clade I in Central and Eastern Africa, it’s not surprising to see a case identified in a traveler,” Daigle remarked. “Quick identification and management of any mpox cases are critical to preventing its spread.”

What is the Status of Mpox in the U.S.?

As of Thursday, there have been no reported instances of clade I mpox in the U.S. The federal government indicates that the risk remains low, with the CDC monitoring the situation concerning the case in Europe. A few cases of the milder strain of the virus continue to emerge weekly in the U.S.

The CDC has circulated a health alert and travel advisory regarding the stronger strain of mpox in Congo and surrounding areas, recommending that health providers remain vigilant and inquire about patients’ recent travel to affected regions.

Since 2022, the U.S. has experienced outbreaks of clade II mpox, predominantly among men who have sex with men, as well as some cases in nonbinary and transgender individuals, according to recent CDC statistics. In total, more than 32,000 infections have been recorded in the U.S., with 58 fatalities linked to mpox.

Most initial U.S. cases were concentrated in New York City.

On Thursday, New York City Health Commissioner Ashwin Vasan urged prompt action to prevent the spread of clade I, stating that “we cannot let uncertainties delay our preparations; the time to act is now.”

“As we have learned repeatedly, our fates are interconnected, and we cannot simply stand by and assume that suffering in another nation will not affect us,” Vasan emphasized in a statement. “Prevention means investing in one another just as much as in ourselves. It is not enough to wait and see.”

Should I get vaccinated?

Vaccines are recommended for individuals in high-risk groups. The JYNNEOS vaccine, which consists of two doses spaced at least four weeks apart, offers protection against both clade I and clade II of the virus.

Since August 2022, over 1 million vials of the JYNNEOS vaccine have been acquired and distributed across the U.S., as reported by agency spokesperson Spencer Pretecrum.

However, more than 75% of individuals deemed at risk in the U.S. have yet to receive full vaccination against mpox, according to a CDC analysis. Many who begin the vaccination process do not return for their second dose; estimates suggest that only about 25% of those who received the initial shot return for the second one. To achieve complete protection against the virus, both doses are necessary.

The vaccine has proven to be highly effective; a recent CDC report indicated that fewer than 1% of fully vaccinated individuals became infected. For those who were infected, symptoms were less severe compared to those unvaccinated.

Federal health officials recommend this vaccine for anyone aged 18 and older who fall into these categories:

• Gay men; bisexual men; men who have sex with men; as well as transgender and nonbinary individuals, particularly if they have had at least one recent sexually transmitted infection diagnosis, multiple sexual partners, or have engaged in sexual activities at venues where mpox transmission was known to occur.
• Sexual partners of individuals in the previous category, or those planning to engage in similar sexual experiences.

What about booster shots?

According to the CDC, booster shots are not currently recommended for those who have completed the two-dose series. Dr. Trish Perl, an infectious disease expert and professor at the University of Texas Southwestern Medical Center in Dallas, noted that the mpox vaccine grants long-lasting immune protection.

Mpox shares a connection with smallpox, a disease that was eradicated globally in 1980, and smallpox vaccines have remained effective over the years, as noted by Perl.

While smallpox vaccines provided lifelong immunity, it’s still too early to determine if the protection from JYNNEOS will last as long, she added.

How is the U.S. addressing the global outbreak?

Experts emphasize that vaccination will be crucial in the U.S. and stress the need for enhanced surveillance of mpox cases in communities.

Surveillance acts as the public health system’s “eyes and ears,” Perl told YSL News. If more cases are detected, public health officials can ramp up responses to contain its spread.

Experts also highlight the necessity of informing the public about risks and preventive measures. Scott Bertani from the National Coalition for LGBTQ Health, which has set up a resource center for mpox, pointed out that tackling the virus requires a “status neutral approach” in healthcare. This implies encouraging healthy practices to prevent HIV, STIs, and mpox while promoting regular healthcare access.

“It is crucial for our community this summer to engage in conversations regarding our health,” he remarked to YSL News. “This will help avert complacency and ensure we acknowledge the issues affecting our community.”