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Monkeypox cases are on the rise. How is the virus transmitted sexually?

The majority of monkeypox infections in this current outbreak have come from sexual activity, but monkeypox is not an STI, according to experts.
/ Source: TODAY

As the world still grapples with the latest wave of COVID-19, another viral disease has taken the spotlight: monkeypox.

The virus, which previously circulated primarily in West and Central Africa, has now been declared a public health emergency by the Biden administration. Last month, the World Health Organization also declared the outbreak a public health emergency of international concern.

RELATED: As monkeypox outbreak spreads, these pictures can help you identify symptoms

Data from Aug. 4 shows more than 26,800 cases have been reported in 88 countries, including at least 7,102 cases in the United States, according to the U.S. Centers for Disease Control and Prevention.

Research shows the majority of infections in this current outbreak have been spread through sexual activity, in particular sex between men, which makes this outbreak different from past ones.

What is monkeypox, and where does it come from?

Monkeypox is a viral disease caused by the monkeypox virus (MPV), which can spread from animals to humans or between humans. The monkeypox virus is from the same family as the smallpox virus, and it's not related to chickenpox, according to the CDC.

A textbook case of monkeypox typically starts out with flu-like symptoms such as a fever, fatigue, or muscle aches and swollen lymph nodes, and usually within five days patients develop a rash of painful raised lesions, Dr. Scott Roberts, associate medical director of infection prevention for the Yale School of Medicine, told TODAY. The rash usually starts on the face and mouth and then spreads to other parts of the body. The lesions usually start out as pimple-like then become pus-filled and eventually scab or crust over.

However, in this outbreak, symptoms have looked different from the classic clinical picture of monkeypox, NBC News reported. Many patients have developed lesions on their genitals or other parts of their body before the flu-like symptoms or they never develop the flu-like symptoms.

Up until now, outbreaks of monkeypox have been smaller.

In previous cases of human-to-human transmission in Africa, “a person would get monkeypox, then it might spread within the household from eating and living together, and it would not spread further from that,” Dr. Stuart N. Isaacs, infectious disease specialist and associate professor of medicine at the Perelman School of Medicine at the University of Pennsylvania, told TODAY. “So what’s being seen now is something very unusual in the amount of person-to-person spread that is going on.”

According to the CDC, before the 2022 outbreak, almost all monkeypox cases outside of Africa were linked to travel to endemic countries or imported animals.

How does monkeypox spread through sex? 

“The predominant mode of transmission is close, skin-to-skin contact,” Dr. Paul Adamson, infectious disease physician and assistant clinical professor of medicine at the David Geffen School of Medicine at University of California, Los Angeles, told TODAY. 

Skin-to-skin contact can occur during sexual activity, such as oral, vaginal or anal sex, and foreplay. But transmission can also happen during other intimate activities like kissing, cuddling or massaging, according to the CDC, as the virus can spread through direct contact with an infected person’s lesions or scabs, and bodily fluids.

“The lesion itself is really full of virus, and that’s mostly how it spreads,” said Roberts, adding that the virus is believed to enter the body through mucous membranes, such as those in the mouth, eyes, genitals and rectum, or a break in the skin. (In a non-sexual scenario, a person may contract monkeypox from touching a lesion with their hand and then touching their mouth or eyes, Roberts said.)

Monkeypox sores are more likely to arise in the places where the virus entered the body, Adamson added, but they may appear anywhere on the body after the rash begins: “Some patients we’ve seen have the predominant number of lesions on their genitals, but they’re also finding lesions in other places, like on the bottom of their feet or on their chest or arms.”

The virus can also spread through contaminated objects or fabric and respiratory secretions, which can also be involved in sexual activity, the experts noted. (In order for the virus to enter through the respiratory tract, prolonged contact, defined by the CDC as within 6 feet for three hours, per Roberts, is necessary.)

“By and large, what we’ve seen so far has been sexual transmission, and we think that’s because it brings a certain kind of closeness that allows for the MPV to spread,” Dr. Andrew Goodman, medical director of Callen-Lorde Community Health Center in New York City, told TODAY.  

So, given how monkeypox can spread, condoms will not prevent transmission.

“It’s possible that using condoms might reduce the risk of getting lesions on your penis and anus, in the rectum … but condoms wouldn’t necessarily prevent skin-to-skin contact in other areas that are outside the area protected by the condom,” Adamson explained.

In addition, condoms won't stop spread from respiratory droplets. Roberts pointed out. “If somebody has a mouth lesion and they end up kissing somebody, there’s probably a lot of transmission of virus that way,” he said.

At the moment, it's unclear if monkeypox can spread through semen or vaginal fluids. A recent study in the New England Journal of Medicine of 528 monkeypox patients diagnosed between April 27 and June 24, 2022, showed there was “no clear evidence of sexual transmission through seminal or vaginal fluids,” the study authors wrote. But scientists are still researching this, per the CDC.

Bottom line: “The more virus you get exposed to, the higher the chances of you getting infected. … Coming into close, skin-to-skin contact with someone who has lesions that are teeming with virus is the highest risk,” said Adamson. 

Monkeypox is not a sexually transmitted infection, experts say

“The biggest myth I’ve seen is the unfortunate myth that this is sexually transmitted or only associated with men who have sex with men. That’s not the case,” said Roberts.

Although the overwhelming majority of infections in this current outbreak are among men who have sex with men, according to the WHO, anyone can get monkeypox. In the U.S., there have been five cases of monkeypox in kids and one case in a pregnant woman.

“This is not a sexually transmitted disease per se, but it is certainly an 'intimacy-communicable' disease,” Dr. W. Ian Lipkin, director of the Center of Infection and Immunity at the Mailman School of Public Health at Columbia University, told TODAY. He emphasized the virus can spread through other kinds of activities, like sharing sheets or towels that touched an infected person’s lesions.

So why is monkeypox spreading primarily among this community?

“We don’t think there’s anything about the ways that (men) have sex with each other that exclusively caused the spread of this particular virus,” Goodman explained. “The belief is the disproportionate effect for men who have sex with men really just has a lot to do with sexual networks, groups that will have this close contact or sexual contact with each other, and not necessarily a lot of activity outside of that group."

“We don’t expect that to be exclusive or to be the pattern forever, necessarily,” Goodman continued, adding that transmission between members of the same household has already been documented in this outbreak, indicating that the virus has broken out of the original community it affected. 

“We’re thinking a lot about how we talk about this because of stigmatization, and trying to make sure that folks get the information that they need, while not increasing or worsening any stigma that has historically affected our community,” he said.  

Right now, public health efforts should be focused getting resources (including vaccines) to the most affected communities as quickly as possible to curb transmission, said Adamson.

The origins of the current monkeypox outbreak, and how it is spreading between people, is an active area of research and guidelines around vaccination or prevention may change as scientists get more information. 

“What we know today might be different tomorrow, that’s the challenge,” said Goodman.