Mpox (formerly monkeypox) Virus Updates

Human mpox virus (formerly monkeypox), also known as hMPXV, is an infectious disease caused by the mpox virus.

The virus is part of a family of viruses called poxviruses that include smallpox. Poxviruses cause a painful rash that can look like pimples or blisters. A poxvirus infection can also cause health problems and, rarely, death.

The virus was first reported in 1958 after it sickened monkeys in a research center in Denmark. The virus originally became known as monkeypox, even though the monkeys were not the source. Scientists believe rodents carry the virus.

In November 2022, the World Health Organization officially began using a new preferred term “mpox” as a synonym for monkeypox. Both names will be used simultaneously for one year while “monkeypox” is phased out.

The most common symptom of mpox is a rash or sores that often look like pus-filled pimples or blisters. These pimples can burst, leading to painful or itchy open sores that contain live, infectious virus.

These sores can be present all over the body or limited to certain body parts. Other symptoms include fever, headache, muscle aches, swollen lymph nodes, chills, exhaustion, and respiratory symptoms such as a sore throat, congestion or coughing.

Symptoms usually start within three weeks of being exposed to the virus.

No one in the U.S. and very few people worldwide have died from the current outbreak to date. It can cause more severe disease in children and people with compromised immune systems. In central and western Africa, where the disease is more common and where different strains that cause more severe disease circulate, mpox has an estimated mortality rate of somewhere between 1% and 10%.

The virus is more difficult to spread than the cold, flu and COVID-19.

It mostly spreads through direct or indirect contact with an infected person’s skin lesions, bodily fluids or personal items, such as clothing, bedding or towels.

OHSU Health experts say that casual contact, such as a handshake, is highly unlikely to spread mpox. Scientists are studying whether the virus can spread through airborne droplets, but believe that’s rare.

If you are pregnant and become infected with mpox, you can pass it:

• To your fetus through the placenta.
• To your newborn during close contact after birth.

If you develop a rash or other mpox symptoms, you should contact your primary care physician or a healthcare provider, especially if you are in a high-risk group or have been exposed to someone with mpox. The virus can be diagnosed by a health professional who collects a sample from a lesion and runs it through a PCR lab test, similar to the lab tests offered for COVID-19.

It generally takes 2-4 weeks for the lesions to heal, at which point a person is no longer infectious. Once people have recovered, the disease has run its course and they can no longer spread it to anyone else.

Those in high-risk groups should speak with their health care provider about getting vaccinated against mpox. People living with HIV/AIDS or other conditions that weaken the immune system are more vulnerable to becoming seriously ill if they get mpox, and should proactively speak with their health care provider to ensure their immune systems are sufficiently boosted.

OHSU Health experts recommend that you avoid:

• Having unprotected contact with an infected person’s skin lesions, body fluids or personal items.
• Having lengthy face-to-face contact (within 6 feet) with an infected person without masks.

The CDC recommends that people consider limiting sex partners and avoiding sex parties to reduce the risk of getting the virus until they are vaccinated.

If you share a household or health care setting with an infected person, you can use common household disinfectants to kill mpox on shared surfaces and personal items. In the home, contaminated bedding or clothing should not be shaken, but instead folded or rolled up, and then washed in a washing machine with detergent.

Those who become infected should isolate themselves to prevent spreading it to others.

There are two vaccines that can prevent mpox infection. The JYNNEOS vaccine is a two-dose injection that’s approved by Food and Drug Administration for mpox. Another vaccine, ACAM2000, is FDA-approved for smallpox.

Because mpox and smallpox are related, ACAM2000 can also be used for mpox. However, ACAM2000 is not recommended for some populations, including people who are pregnant or breastfeeding, have weakened immune systems, or have certain skin conditions, such as eczema or atopic dermatitis.

If you think you have been exposed to mpox:

• Check yourself for symptoms for 21 days after your most recent exposure. This includes taking your temperature twice a day to check for fever. (The Oregon Health Authority recommends checking for a new rash, a fever of 100.4 or higher, swollen lymph nodes and chills.)
• Stay away from group events.
• Avoid public transportation.
• Avoid donating blood, tissue, breast milk, semen or organs.

If you develop symptoms, you are encouraged to:

• Stay away from people and pets (isolate).
• Seek testing and medical care.
• Cover your lesions if possible.
• Wear a mask.
• Fold or roll up infected bedding or clothing, and wash it in a washing machine.

If you have been exposed, or are in a high-risk group such as men who have sex with other men call your health care provider or your local public health department to ask for a vaccine:

• Oregon health departments
• Washington health departments
• Clackamas County Health, Housing and Human Services
• Multnomah County Health Department
• Washington County Health & Human Services

Most people who get mpox recover without treatment in 2-4 weeks.

For more serious cases, the CDC and FDA allow the use of tecovirimat, or TPOXX, an antiviral drug approved for smallpox.

Although vaccination aims to prevent infection to begin with, even getting vaccinated shortly after being infected may reduce symptom severity or prevent the development of symptoms.

No. Although anyone can potentially be infected with mpox, most Americans older than 60 have received the smallpox vaccine, which also protects against mpox because the two viruses are related.

Scientists are working to understand how much prior smallpox vaccination protects against mpox. For example, OHSU researchers have found the smallpox vaccine provides immunity up to 75 years after a single childhood vaccination against both smallpox and mpox.

No. Mpox is a known virus that is much harder to spread than the virus that causes COVID-19. There is already an approved vaccine to prevent mpox. The severity of mpox illness can be reduced through vaccination even if it is given 3-4 days after a known exposure, and there are antiviral medications that can be used to treat mpox.

No. While people can get mpox during sex, it is not considered a sexually transmitted disease because it can spread in other ways.