Is Mpox (Monkeypox) Still A Concern In The US?

A cluster of mpox (formerly monkeypox) cases appeared in the United Kingdom in May 2022, and the UK government confirmed an outbreak of the rare viral disease.¹ Since then, public health officials have confirmed other cases across Europe and the Americas.

With cases increasing rapidly, the World Health Organization (WHO) Director-General declared the global outbreak a Public Health Emergency of International Concern (PHEIC) on July 23, 2022.²

By August 2022, 99 countries reported cases of mpox, and 92 of these countries had never seen mpox cases before.² Mpox is endemic (native) to West and Central Africa, and the first recognized case was linked to travel to Nigeria.³ Mpox was quickly taking hold in new countries.

Near the end of November 2022, the WHO renamed the disease “mpox.”

They oversee naming new diseases, and they received complaints that monkeypox “plays into racist and stigmatizing language.”⁴

Consequently, the two names will be used interchangeably for a year before the term monkeypox gets phased out.

Human monkeypox was given its name in 1970 — long before the WHO released a best practices guide for naming diseases in 2015. They recommend that new disease names minimize “the unnecessary negative impact of names on trade, travel, tourism or animal welfare, and avoid offending any cultural, social, national, regional, professional or ethnic groups.”

Mpox similarities to smallpox

Mpox is a viral, zoonotic disease; it spreads from human to animal and vice versa. Examples of these diseases include the bubonic plague and rabies.

Mpox is similar to smallpox; it can spread from infected humans, animals, and contaminated materials. However, mpox is less transmissible and lethal than smallpox.⁵

The mpox virus belongs to the Orthopoxvirus genus in the family Poxviridae.⁶ This classification of disease also includes cowpox, variola virus (which causes smallpox), and vaccinia virus (this virus is also part of the vaccine used to develop immunity to smallpox).⁷

Mpox can enter your body through broken skin, the respiratory system, eyes, nose, and mouth. The fact that it spreads rapidly between infected people, animals, and materials caused mpox to become a significant public health concern.

The mpox virus has two viral clades (a group of organisms with a common ancestor).

A clade from the Congo Basin is known to be more transmissible and cause more severe symptoms, with a mortality rate of 10.6%.⁸ However, the milder West African clade is associated with the current global outbreak and has a mortality rate of 3.6%.

The mortality rate is from historical data in the areas where the virus originated. Healthcare access in these countries is often minimal. Similar to covid-19 reporting, the studies citing a mpox 3.6% mortality may under-represent mild cases.

We have known about mpox (monkeypox) since 1958

While it may be the first time you’ve heard of monkeypox, it’s not a recent discovery. Scientists observed mpox in 1958 when a Danish laboratory’s research monkeys had two outbreaks of a “pox-like disease,” hence the name.⁹

Mpox was first recorded in humans in a nine-month-old boy in Zaire (now the Democratic Republic of the Congo [DRC]) in 1970, two years after successful efforts to eradicate smallpox in the area.

Scientists discovered that children under ten comprised 83% of all cases during 1970-1979, and the case fatality rate was 17%.¹⁰ At this point, mpox was present in five countries: DRC, Liberia, Nigeria, Sierra Leone, and the Ivory Coast. Not only was the DRC the origin of the virus, but it also remains the country with the most regularly occurring cases today. 

Mpox appears outside Africa in 2003

International travel and imported animals have widened the spread of mpox. The first mpox case outside of Africa occurred in 2003.¹¹

US health officials linked this outbreak of over 70 cases to infected pet prairie dogs. The owners housed them with Gambian pouched rats and dormice imported from Ghana.¹²

With international travel, migration, and globalization as factors, viruses can spread quickly. There were reports of mpox in travelers from Nigeria to Israel, the UK, Singapore, and the US.¹³ Multiple cases of mpox arose in several non-endemic countries in May 2022, which leads us to where we are today.

So, what else is known about how the mpox virus spreads?

Zoonotic transmission

Many African animals have mpox, including squirrels, monkeys, and rodents. Direct contact with bodily fluids, blood, or lesions of an infected animal's skin, mouth, or nose can spread mpox (zoonotic transmission).

This type of virus transmission poses less risk if you’re in Europe or the Americas. Human-to-human transmission is the more significant threat, as this recent outbreak spreads from people who have never been to endemic areas. So, how does it spread across the human population?

Transmission during sexual activity

You can catch mpox from an infected person if you:

  • Come into contact with their bodily fluids, including semen, saliva, or blood

  • Have contact with mpox lesions on their skin and inside their mouth and nose

  • Inhale respiratory droplets

  • Touch things that have been in contact with infected bodily fluids, like bedding

Mpox isn’t categorized as a sexually transmitted infection (STI) because you can also get it from other types of contact. Still, most confirmed cases appear through sexual activity and contact with bodily fluids, and infectious skin lesions.¹⁴

Most mpox infections have occurred in young or middle-aged men, many of whom have sex with men (MSM).¹⁵ ¹⁶ In Canada, Spain, and the UK, sexual health clinic workers identified many instances of infection. (In countries where mpox infections are not new, it affects mainly children, not adults).

What are the symptoms of mpox infection?

Mpox has a relatively short incubation period of 6–13 days but may range from 5–21 days. (An incubation period is how long it takes for symptoms to appear after infection).

The WHO divides the infectious period into two stages: Invasion and skin eruption.¹³ These stages have different symptoms, but you can spread mpox as soon as symptoms start.

During the invasion period of up to five days, you may have these symptoms:

  • Intense headache

  • Backache

  • Muscle aches

  • Fever

  • Lack of energy

  • Swollen lymph nodes

The skin eruption period typically starts within 1–3 days of fever onset. As the name suggests, this is when the rash appears, causing numerous lesions — ranging from just a few to several thousand — and usually affecting the face, arms, or legs more than the trunk.

According to the Australian Department of Health, “the rash shows on the face in the vast majority of cases (95%); palms of the hands and soles of the feet (75%); inside of the mouth (70%); genitalia (30%) and eyes (20%).”¹⁷

The rash has several stages:

  • Flat, round lesions grow into slightly raised bumps

  • A clear fluid fills these bumps

  • The fluid turns yellow

  • The bumps crust and fall off

  • A new layer of skin is visible (at which point you’re no longer infectious)

If you’re concerned that your lesions indicate mpox, see a healthcare professional. They will test you for the virus by swabbing your lesions and sending the swab off to a lab.

Minimizing the chance of spreading the virus is crucial. You should avoid contact with other people and animals.

Ideally, use a separate bedroom and bathroom, do not share items with other people (towels, cutlery, bedding), and try to avoid going out.

If you have to leave home in an emergency, wear a mask and ensure you cover all lesions.

Recovering from mpox

Mpox is typically a self-limiting disease — meaning most people won’t need treatment and usually heal within 2–4 weeks.¹⁸

However, it can cause considerable discomfort and pain. Your doctor will likely recommend rest, over-the-counter pain medications, and plenty of fluids.

If you have a rash on your genitals or rectum, you may need prescription medication to prevent complications like a secondary infection.

Mpox symptoms typically go away on their own after a few weeks.

What smallpox has shown about vaccination

Given that smallpox medication is sometimes given for mpox, perhaps you’re wondering if a smallpox vaccine could also prevent mpox. First, let’s delve into some smallpox vaccination history and find out how we got to where we are now.

Smallpox is a devastating infectious disease that is at least 3,000 years old.¹⁹

  • Evidence of smallpox exists in Egyptian mummies dating back to the third-century BC.²⁰

  • It killed an estimated 300–500 million people in the 20th century.²¹

  • As many as 30% infected with smallpox died.²⁰

  • 90% of all blindness cases in Vietnam in 1898 were due to smallpox.

Science finally came to the rescue when Edward Jenner created the smallpox vaccine in 1796. It was a major scientific innovation: the first successful vaccine in history.

The first place to introduce compulsory vaccinations was Bavaria (a state in Germany) in 1807.²²

In time, and after seeing how effective the vaccine was, other countries followed suit. The Pan American Health Organization (PAHO) engineered the first hemisphere-wide vaccination program in 1950.²³ ²⁴ Over the next decade, it eliminated smallpox from all the Americas except Argentina, Brazil, Colombia, and Ecuador.

In 1958, the Soviet Union proposed that the WHO commit itself to a global eradication program. It was agreed upon in 1959, and many countries, including China, started mass vaccination campaigns and eliminated the disease.

By 1975, smallpox only survived in the Horn of Africa. After overcoming logistical issues in the area, scientists eradicated smallpox in 1980, marking an incredible achievement.²⁵ The last natural case arose in Somalia in 1977, affecting an unvaccinated 23-year-old man, Ali Maow Maalin.²⁶ He survived and later became an advocate and volunteer for polio vaccination campaigns.

Inoculating against mpox with JYNNEOS vaccine

Long after the extensive worldwide smallpox vaccination efforts, the US FDA announced the approval of JYNNEOS, Modified Vaccinia Ankara (MVA), on September 24, 2019 — to inoculate adults 18 years and older determined to be at high risk for smallpox or monkeypox infection.²⁷

More recently, to create a 5x increase in available doses, the FDA issued an emergency use authorization (EUA) on August 9, 2022, for healthcare providers to use JYNNEOS in people at high risk of mpox, including individuals under 18 years old.²⁸ JYNNEOS is a two-dose vaccine (28 days apart), and the recent authorization, which allows using a fraction of the original dose.

Medical treatment for mpox

While there isn’t a standard mpox treatment,  if a patient is at significant risk of dangerous complications, especially in a severe case, doctors can prescribe a drug initially developed for smallpox,  the antiviral tecovirimat (also known as TPOXX).²⁹

Tecovirimat is an FDA-approved treatment for smallpox, and the CDC has allowed its use in mpox cases on an experimental basis.

In a tiny May 2022 study published in The Lancet, one participant with mpox received tecovirimat and experienced a shorter illness, less viral shedding, and no adverse effects compared with the other six patients (some of whom received the drug brincidofovir instead).³⁰

There is a National Institutes of Health-funded clinical trial to evaluate the safety and effectiveness of TPOXX.³¹

People under 50 may be more susceptible to mpox infection

In the past, vaccination against smallpox was around 85% protective against mpox.¹³

However, no global smallpox vaccination campaigns have existed for decades (since 1977).

For example, the UK and the US stopped smallpox vaccinations in 1971 and 1972. Some countries, including Australia, and New Zealand, didn’t use widespread mandatory immunization. Instead, they relied upon social distancing and quarantine.

Consequently, many people under 50 who lack a smallpox vaccination may be more at risk from mpox and complications. (Ask your healthcare provider or check your medical record if you’re unsure whether you’ve had a smallpox vaccine).

Who is at the highest risk of mpox infections?

In addition to those born after the smallpox immunization campaigns, newborns, children, and people with compromised immune systems are at risk of severe symptoms, complications, and even death.

Possible serious complications include secondary infections, such as:³²

If you are pregnant or breastfeeding, the CDC states that you may be at a higher risk of serious illness if you catch mpox.

While we have limited information on the impact of mpox during pregnancy, the WHO says the mother can pass the virus through the placenta to the unborn baby, which could cause miscarriage or stillbirth.¹³

You could also give the virus to your newborn baby during or after birth through close contact. There’s currently no evidence on whether breastfeeding with the virus is safe.

We also don’t have any information on whether mpox can increase the chances of your baby having congenital disabilities.

Still, fever is a mpox symptom, and research has linked high maternal fever during early pregnancy with certain neural tube defects (NTDs) such as spina bifida, as well as the risk of congenital heart diseases.³³ ³⁴

Can you avoid catching mpox?

You can take several measures to prevent mpox infection:

  • Avoid close, intimate contact with people infected with mpox

    • Avoid direct contact with lesions or scabs, as they can spread the disease.

    • Air droplets can spread mpox, so close contact is inadvisable.

    • Contact with bodily fluids may spread the disease: One small study found viral DNA in saliva and semen.³⁵

    • Always practice safer sex, but this may not guarantee protection against mpox if you come into contact with other lesions on your partner’s body.³⁶

    • Do not share towels, bedding, toothbrushes, or sex toys. Any material that has come into contact with someone with mpox can be a vector (way of spreading the virus).

  • Stay away from animals with the virus

    • You can contact mpox if an infected animal scratches or bites you.

    • As mpox is zoonotic, you can spread the virus to your pet and vice versa.³⁷ Seek assistance from your local vet if you believe your pet has been exposed.

  • If you can’t avoid contact

    • Wash your hands often.

    • Use personal protective equipment (PPE), like goggles, masks, and gloves.

The shrinking number of mpox cases in the US

Fortunately, between August and October of 2022, daily mpox cases in the US dropped from nearly 500 a day to closer to 100 newly reported cases a day.³⁸

Transmission prevention, vaccinations, and increased immunity have not yet eliminated mpox. Still, there has been a significant impact — numbers are down to 84,471 confirmed cases worldwide in 110 countries as of January 1, 2023, and three cases in the US as of January 11, 2023.² ³⁹

The lowdown

There are things we can do to minimize our mpox risk. Whenever possible, staying away from infected people and animals is the easiest way to avoid the virus. With most cases occurring in men who have sex with men, communication with your sexual partners is vital. If you have a new lesion or notice a new one on your partner, avoid intimate contact and seek testing.

Mpox symptoms typically go away on their own after a few weeks. Mpox is still rare and is usually a mild, self-limiting disease. However, certain people are more at risk from the virus, such as newborns, children, immunocompromised people, and pregnant people. If you or your loved ones are at risk, speak to your healthcare provider or use this tool to locate the nearest mpox vaccine location online.⁴⁰

  1. Monkeypox cases confirmed in England – latest updates | Gov.Uk

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  3. Monkeypox - United Kingdom of Great Britain and Northern Ireland | World Health Organization (WHO)

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  13. Monkeypox | World Health Organization (WHO)

  14. Epidemiological update: Monkeypox outbreak | European Centre for Disease Prevention and Control

  15. Investigating the monkeypox outbreak (2022)

  16. A novel international monkeypox outbreak (2022)

  17. Monkeypox ‘able to be contained’: Professor Michael Kidd | RACGP

  18. Treatment information for healthcare professionals | Centers for Disease Control and Prevention (CDC)

  19. Smallpox | World Health Organization (WHO)

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  21. Smallpox | Our World in Data

  22. Historical context and the roots of Jenner's discovery (2016)

  23. Public health (1999)

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  25. Smallpox | World Health Organization (WHO)

  26. The world's last smallpox patient | Gavi

  27. FDA approves first live, non-replicating vaccine to prevent smallpox and monkeypox | U.S. Food & Drug Administration

  28. Monkeypox update: FDA authorizes emergency use of JYNNEOS vaccine to increase vaccine supply | U.S. Food & Drug Administration

  29. Patient’s guide to Mpox treatment with tecovirimat (TPOXX) | Centers for Disease Control and Prevention (CDC)

  30. Clinical features and management of human monkeypox: a retrospective observational study in the UK (2022)

  31. A5418: Study of tecovirimat for human monkeypox virus (STOMP) | AIDS Clinical Trial Group

  32. Mpox (Monkeypox) (2022)

  33. Periconceptional maternal fever, folic acid intake, and the risk for neural tube defects (2017)

  34. Maternal fever during preconception and conception is associated with congenital heart diseases in offspring (2021)

  35. Frequent detection of monkeypox virus DNA in saliva, semen, and other clinical samples from 12 patients, Barcelona, Spain, May to June 2022 (2022)

  36. Safer sex, social gatherings, and Mpox | Centers for Disease Control and Prevention (CDC)

  37. Pets in the home | Centers for Disease Control and Prevention (CDC)

  38. Mpox has faded in the US. Who deserves the credit? | AP News

  39. U.S. Mpox case trends reported to CDC | Centers for Disease Control and Prevention (CDC)

  40. Mpox vaccine location online | Monkeypox Vaccine Locator

Victoria is a writer from the UK with a keen interest in health and science. She loves writing about mental health, scientific advancements, and dispelling pseudoscience. When she’s not writing sass-laden articles, she walks her rescue dogs, giggles at anxiety memes, eats chocolate, and absorbs useless knowledge for quiz shows.

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