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Monkeypox Disease: Symptoms, How It Spreads and Whether We Should Worry

what’s happening

The US and other countries where monkeypox doesn’t normally spread are experiencing outbreaks. Monkeypox is already endemic in some countries.

why it matters

Even though the disease has appeared in the US before, outbreaks of monkeypox in more countries pose a public health threat.

What it means for you

Monkeypox is spread through very close contact. If you have an unexplained rash or skin blemish and think it could be monkeypox, seek medical care.

In a media statement Thursday, the US Centers for Disease Control and Prevention reiterated that the health agency believes monkeypox is spread primarily through close contact: the skin-to-skin contact you’d have with a sexual partner, sharing clothing or bedding or prolonged face-to-face interactions, like the kind you’d have when living or caring for someone with monkeypox.

However, unlike many monkeypox cases in the past, some people in the current outbreak are reporting more localized rashes or blemishes that look like a pimple or blister, CDC Director Rochelle Walensky said last week, as reported by NBC News. This is opposed to the more “classic” appearance of monkeypox, which often leads to widespread rash and flulike symptoms.

Monkeypox is a disease caused by an orthopoxvirus, and the virus that causes it belongs to the same family as the viruses that cause smallpox and cowpox. Monkeypox is endemic in West and Central Africa. Reports of it are rare in the US but not unheard of. (There were two reported cases last year, and 47 cases in 2003 in an outbreak linked to pet prairie dogs.)

In the current US outbreak, there have been at least 65 cases of monkeypox across 18 states, according to the CDC. The US confirmed its first case of monkeypox in mid-May, joining the list of other countries that don’t typically report cases of the disease (in other words, in countries where monkeypox isn’t endemic). Men who have sex with men are being disproportionately affected in the current US outbreak as well as other countries.

“With the number of cases that have been diagnosed in other countries, it was only a matter of time before there was a case in the United States,” said Dr. Amesh Adalja, an infectious-disease expert and senior scholar at the Johns Hopkins Center for HealthSecurity.

Adalja said scientists are trying to “get a handle on what’s happening epidemiologically” to explain why the outbreaks appear different from other outbreaks that’ve occurred outside of Africa, where most cases have been concentrated.

“I think it’s something to watch and see how extensive the spread may be, but there’s no reason for alarm or panic over any of this,” Adalja said. Monkeypox isn’t new, I have added, and we already have some tools to stop the spread, including smallpox vaccines.

Here’s what we know.

Monkeypox got its name because it was first detected in monkeys that were being kept for research.

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What is monkey pox? How severe is it?

Monkeypox is a zoonotic disease, which means it’s transmitted from animals to humans. It’s caused by an orthopoxvirus, which also causes smallpox, though smallpox is considered more clinically severe than monkeypox.

There are two “clades” of monkeypox virus, according to the World Health Organization, including the West African clade and the Congo Basin clade. The West African strain, which has been identified in the recent cases, according to a May 26 presentation by the WHO, has a fatality rate of less than 1%. The Congo Basin or Central African clade has a higher mortality rate of up to 10%, per the World Health Organization.

Monkeypox was first discovered in the 1950s in colonies of monkeys that were being researched, according to the CDC, but it’s also been found in squirrels, rats and other animals. The first human case was discovered in 1970.

How do you catch monkeypox? Does it compare to COVID?

Monkeypox spreads between people primarily through contact with infectious sores, scabs or body fluids, according to the CDC, but it can also spread through prolonged face-to-face contact via respiratory droplets or by touching contaminated clothing or bedding.

At a media briefing earlier this month, Tedros said that most cases in the recent outbreak have been reported in men who have sex with men, who have shown up in sexual health clinics with symptoms. The close contact you have with a sexual partner may expose you to monkeypox, and the current outbreak is linked to social networks or sexual activity within some communities.

Gay and bisexual communities tend to have particularly “high awareness and rapid health-seeking behavior when it comes to their and their communities’ sexual health,” Dr. Hans Henri P. Kluge, the WHO’s regional director for Europe, said in a statement last week, noting that those who sought early health care services should be applauded.

But anyone can be infected with monkeypox — the “close” in close contact is a key element in the transmission of monkeypox. That, along with the fact that the virus that causes monkeypox appears to have a slower reproduction rate than the COVID-19 virus, sets it apart from the ongoing COVID-19 pandemic, Dr. Tom Inglesby, director of the Center for Health Security at the Johns Hopkins Bloomberg School of Public Health, said Tuesday at a media briefing.

While scientists are still learning about monkeypox in the newer outbreaks: “It’s not acting like influenza or COVID or chicken pox or measles — things that spread quickly in an unvaccinated community,” Inglesby said. “It’s acting much more like a disease that requires close contact.”

“It’s not a situation where if you’re passing someone at a grocery store, they’re gonna be at risk for monkeypox,” Dr. Jennifer McQuiston, deputy director at the Division of High Consequence Pathogens and Pathology, said at a May briefing with the CDC.

Because many of the recent cases of monkeypox in Europe have resulted in lesions in the genital region and resemble symptoms of sexually transmitted infections like herpes, you should ask to be evaluated if you have an unexplained rash in your genital region, Dr. John Brooks, epidemiologist in the Division of HIV/AIDS Prevention, said at a May CDC media briefing.

Monkeypox vs. smallpox: How contagious are they?

Symptoms of monkeypox in humans are similar to (but milder than) smallpox, which the WHO declared eliminated in 1980.

A monkeypox infection usually begins with flu-like symptoms, including fatigue, intense headache, fever and swollen lymph nodes. Within one to three days of a fever developing, according to the CDC, a rash typically develops (historically, it started on the face before spreading, but this isn’t always the case). The rash or monkeypox lesions can be flat or raised, full of clear or yellowish fluid and will eventually dry up and fall off.

Illness typically lasts for two to four weeks. The incubation period ranges from five to 21 days, according to the CDC.

Importantly, Adalja said: “Monkeypox is not contagious during the incubation period, so it doesn’t have that ability to spread the way certain viruses like flu or SARS-CoV-2 can.”

Pus-filled monkeypox lesions on a hand

Monkeypox lesions progress through a series of stages before scabbing, according to the CDC.

While traditionally the rash starts on the face before becoming more widespread, monkeypox blemishes can be limited and aren’t always necessarily accompanied by flulike symptoms.

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Is there a vaccine for monkeypox?

And it is. The US Food and Drug Administration has approved JYNNEOS to prevent monkeypox as well as smallpox. Because monkeypox is so closely related to smallpox, vaccines for smallpox are also effective against monkeypox. In addition to JYNNEOS, the US has another smallpox vaccine in its stockpile, called ACAM2000.

The US Department of Health and Human Services is adding an additional 36,000 doses of monkeypox vaccine to its stockpile, Reuters reported Monday. Vaccines may be distributed to people who have high-risk exposures to monkeypox, CNBC reports, and they aren’t being given to the general public.

In the UK, higher-risk contacts of people who have monkeypox have been offered vaccines. This type of targeted vaccination is what Adalja calls “ring vaccination,” where health officials isolate the infected person and vaccinate their close contacts to stop the spread. Antivirals that work against smallpox would also have an impact against monkeypox, he said.

Dr. Daniel Pastula, chief of neuro-infectious diseases and associate professor of neurology, medicine and epidemiology at the University of Colorado Anschutz Medical Campus, said the vaccine is used in people who’ve been exposed but aren’t yet showing symptoms of monkeypox , because the incubation period for the disease is so long.

“Basically what you’re doing is stimulating the immune system with the vaccine, and getting the immune system to recognize the virus before the virus has a chance to ramp up,” Pastula said.

Although health care and lab professionals who work directly with monkeypox are recommended to receive smallpox vaccines (and even boosters), the original smallpox vaccines aren’t available to the general public and haven’t been widely administered in the US since the early 1970s. Because of this, any spillover or “cross-protective” immunity from smallpox vaccines would be limited to older people, the WHO said. According to the WHO, vaccination against smallpox was shown to be about 85% effective at preventing monkeypox.


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The big pictures

It’s helpful to be aware of the symptoms of monkeypox, especially if more cases develop in the US, according to Pastula, but there’s no cause for panic.

“This shows the need for public health,” Pastula said. “As we saw with COVID, it is so important to have a robust public health system, and to support our public health system.”

It also calls attention to the wide variety of viruses we live with. All zoonotic diseases (which include COVID-19) have the potential to be serious, which is why monitoring them is so important, he said.

“I think this shows that there are a lot of potential zoonotic threats — these are diseases that can hop from animals to humans,” Pastula said. This exemplifies the need for public health surveillance, he said, “but it also really shows that we should be careful and deliberate in our interactions with both wild animals and domestic animals.”

It’s also a developing situation, he said, so recommendations made by public health officials will change as the information does — the same goes for all diseases and new science.

The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.

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