As more monkeypox cases emerge around the world, health officials are releasing doses of stockpiled vaccines to help control the outbreaks.

Monkeypox is in the US. Here's what you need to know.

Monkeypox cases emerge worldwide

Monkeypox is a rare viral infection that begins with flu-like symptoms and progresses to a distinctive rash on the face and body. Most infections resolve within weeks, but some cases can be fatal, according to the World Health Organization (WHO).

Although the virus is rarely seen outside of West and Central Africa, where it is endemic, more than a dozen countries worldwide, including the United States, Canada, and Spain, have recently reported monkeypox cases. As of Monday, there were more than 100 confirmed cases, and dozens more are being investigated.

"We do not usually see this level of apparently sustained spread in outbreaks occurring outside of endemic regions and not associated to travel or animal exposure," said Boghuma Titanji, an infectious diseases physician at Emory University.

In the United States, health officials have confirmed one monkeypox case in a man from Massachusetts and are investigating six other presumptive cases—one each in California, Florida, New York, and Washington, and two in Utah. According to Jennifer Mcquiston, a deputy director at CDC, all the U.S. cases are men who have a history of international travel.

According to WHO, many of the recent monkeypox cases have been identified in men who have sex with men, suggesting that the virus may be spreading through sexual contact. On Friday, CDC issued an alert saying doctors should suspect monkeypox if a symptomatic patient "is a man who regularly has close or intimate in-person contact with other men, including those met through an online website, digital application ('app'), or at a bar or party."

"My feeling is this is an outbreak that's happened because, presumably, there was a travel-associated case and then it got into a sexual network and it's a sexual network where there's the possibility for a lot of close contact,” said Jake Dunning, senior researcher in emerging and high consequence infections at the Epidemic Diseases Research Group at the University of Oxford.

In addition, the European Center for Disease Control and Prevention has cautioned those who are infected with monkeypox to avoid close contact with pets since the virus could spread to susceptible animal species. "If human-to-animal transmission occurs, and the virus spreads in an animal population, there is a risk that the disease could become endemic in Europe," the agency said.

Health officials access vaccine stores to contain outbreaks

According to CDC, the United States currently has two FDA-approved vaccines in its emergency stockpile that can be used to prevent monkeypox and contain the outbreak. One of the vaccines is the original smallpox vaccine, and the other is Jynneos, a more recent version of a smallpox vaccine that was approved in 2019 for the prevention of both smallpox and monkeypox.

Although the original smallpox vaccine can be used to prevent monkeypox, it sometimes has adverse side effects and is not suitable for certain patients, such as those with compromised immune systems or with eczema. In comparison, the Jynneos vaccine has fewer side effects, but the United States only has roughly 1,000 doses currently available.

In response to the monkeypox outbreak, Bavarian Nodric, which manufactures the Jynneos vaccine, said it was working to increase production over the new few weeks to provide countries with more doses.

Recently, CDC began releasing doses of the Jynneos vaccines from the U.S. stockpile to individuals who would benefit the most from them, including people who have had close contact with monkeypox patients, health care workers, and people at high risk of developing severe illness from the virus.

Instead of a mass vaccination campaign against monkeypox, which several experts say is unlikely to be needed, health officials may use a "ring vaccination" approach, where close contacts to an infected person are vaccinated, to control the current outbreak, the New York Times reports.

"Hopefully, presumably, monkeypox is still relatively rare right now, and a ring vaccination strategy may well be able to keep it completely at bay," said Bill Hanage, an epidemiologist at the Harvard T.H. Chan School of Public Health.

On Monday, President Joe Biden said that strict quarantine measures are not likely to be needed to control the monkeypox outbreak and that the country has enough vaccine in its stockpile "to deal with the likelihood of a problem."

"I just don't think [the monkeypox outbreak] rises to the level of the kind of concern that existed with COVID-19," Biden said, although he added that "people should be careful" with the virus. (Walker, MedPage Today, 5/23; Kamb, Axios, 5/23; Mandavilli, New York Times, 5/24; Branswell, STAT News, 5/23; Choi, The Hill, 5/23; Roland, Wall Street Journal, 5/23; Chen, Axios, 5/23; Groppe, USA Today, 5/23; Money/Lin, Los Angeles Times, 5/24)