Mpox Resource Center

Mpox is a viral infection caused by a virus similar to smallpox. The source of the disease remains unknown, despite its previous name. However, African rodents and non-human primates — like monkeys — might harbor the virus and infect people. It was first detected in humans in 1970.

There are two main clades, or groups, of mpox: clade I and clade II. Clade I is the virus responsible for the current outbreak in the Democratic Republic of Congo, while clade II is the viral group that caused the outbreak in 2022 and is still circulating in small clusters here in the U.S.

Mpox is a viral “zoonotic” disease (one that can spread from animals to humans and between people). According to the CDC, the virus can spread from person-to-person through:

• Direct contact with the infectious rash, scabs or body fluids.
• Respiratory secretions during prolonged, face-to-face contact or during intimate physical contact.
• Touching items (such as clothing or linens) that previously touched the infectious rash or body fluids.
• Pregnant people can spread the virus to their fetus through the placenta.
• It’s also possible for people to get mpox from infected animals, either by being scratched or bitten by the animal or by eating meat or using products from an infected animal.

Symptoms typically include a fever, intense headache, muscle aches, back pain, low energy, swollen lymph nodes and a skin rash or lesions. The rash is a prominent feature and usually begins within one to three days of the start of a fever. Lesions can be flat or slightly raised, filled with clear or yellowish fluid, and can then crust, dry up and fall off. The number of lesions on one person can range from a few to several thousand.

The rash tends to be concentrated on the face, palms of the hands and soles of the feet. They can also be found on the mouth, genitals and eyes. In the current epidemic, some patients have had a rash present only in the genital area. According to the CDC, the rash goes through different stages before healing completely. The illness typically lasts two to
four weeks. Sometimes, people get a rash first, followed by other symptoms. Others only experience a rash.

If you think you have symptoms or have been in close contact with someone with mpox, contact your health care provider for advice, testing and medical care. If possible, self-isolate and avoid close contact with others. Wash hands regularly and take the steps listed below to protect others from infection.

Clade I mpox, the disease currently causing the outbreak in Central and West Africa, is generally considered more severe with reported mortality rates currently averaging 5%. Although, according to findings from a recent trial conducted on this version of mpox, it’s believed that the mortality rate in a hospital setting is lower than what’s currently being reported.

Clade II mpox is generally considered less severe and has a mortality rate of 0.1-3.6%. Over 99% of people who get this form of the disease are likely to survive.

Newborns, children and people with underlying immune deficiencies may be at risk of more serious symptoms and death from mpox. In the prior epidemics, the reported death rate ranged from 1-11%.

According to the World Health Organization, anyone who has close physical contact with someone who has symptoms of mpox, or with an infected animal are at risk of infection. People who were vaccinated against smallpox are likely to have some protection against mpox infection. However, younger people are unlikely to have been vaccinated against smallpox because smallpox vaccination stopped worldwide after smallpox became the first human disease to be eradicated in 1980. Even though people who have been vaccinated against smallpox may have some protection against mpox, they still need to take precautions to protect themselves and others.

Health care workers are also at higher risk due to potential longer virus exposure when dealing with infected patients. Mpox should be suspected in people with fever, unexplained rash and:

1. Travel in the last 30 days to a country that has recently had confirmed or suspected case of mpox, or
2. Contact with a person with confirmed or suspected mpox, or
3. Intimate sexual contact

According to the CDC, there are a number of measures that can be taken to prevent infection with the mpox virus:

• Avoid close, skin-to-skin contact with people who have a rash that looks like mpox.
• Do not touch the rash or scabs of a person with mpox.
• Do not kiss, hug, cuddle or have sex with someone with mpox.
• Do not share eating utensils or cups with a person with mpox.
• Do not handle or touch the bedding, towels, or clothing of a person with mpox.
• Wash your hands often with soap and water or use an alcohol-based hand sanitizer.

According to the CDC, two vaccines licensed by the FDA are available for preventing mpox infection – JYNNEOS and ACAM2000. CDC does not recommend widespread vaccination against mpox at this time.

People are considered fully vaccinated about two weeks after their second shot of JYNNEOS and four weeks after receiving ACAM2000. 

Mpox symptoms often resolve on their own without the need for treatment. Currently, there is no specific treatment approved for mpox virus infections. However, according to the CDC, antivirals developed for use in patients with smallpox may prove beneficial. Early vaccination of symptomatic individuals may also help prevent severe mpox disease, unlike with COVID where the vaccine needs to be given well before the infection.

Get the vaccine if you:

• Are a gay, bisexual, or other same-gender loving man who has sex with men or are transgender, gender non-binary, or gender-diverse.
• Have had sexual or intimate contact with someone who may have mpox. Get vaccinated as soon as possible after exposure, regardless of your sexual or gender identity. 

AND if you, in the last 6 months, have had or expect to have:

• One or more sexually transmitted infections
• A weakened immune system because of another illness, like HIV
• Sexual or intimate contact with a person who is at risk of mpox Anonymous sexual or intimate contact, or more than one sexual partner

The vaccine is administered in two doses at least 28 days apart. If you only received one dose, it’s never too late to receive your second. You must receive both doses for the best protection. 

Contact the Houston Health Department for more information.