Mpox risks, symptoms and treatment

Mpox is an infectious disease closely related to smallpox. The virus was discovered in 1958, when two outbreaks of a pox-like disease occurred in colonies of monkeys kept for research. The first human case was identified in a child in the Democratic Republic of the Congo in 1970. Despite being named “monkeypox” originally, the source of the disease remains unknown.

Mpox cases are rare, and may be mild. However, the disease can be dangerous for people with weakened immune systems, including young children and people who are pregnant or breastfeeding.

There are two main strains of mpox: clade I, thought to cause more severe illness, and clade II, the relatively milder version that spread to over 100 countries, including the United States, in 2022 and 2023.

A new subtype of the virus, clade Ib, is spreading quickly in the Democratic Republic of Congo and has spread to other nearby and previously unaffected countries in Africa. This recent outbreak is what led to WHO’s global health emergency declaration.

There are currently no known cases of the new mpox strain in the U.S., but doctors are staying on the lookout. For the general public, the risk remains low, the Centers for Disease Control (CDC) says.

The only confirmed case of the new mpox strain outside of the African continent was an adult in Sweden who had visited an African country with clade Ib cases.

Many countries worldwide, including the United States, have continued to see patients with clade II mpox, the version that caused the 2022 outbreak.

Mpox is usually spread via direct person-to-person contact through skin; the respiratory tract; or the mucous membranes in the eyes, nose and mouth. This can occur during sexual activity, kissing, cuddling or touching parts of the body of a person with mpox. Handling clothing or linens that have been worn or used by someone with mpox can also lead to infection.

Additionally, the mpox virus can be shared from an infected pregnant person to their fetus. And transmission is possible from infected animals to people through a bite or scratch, by handling wild game, or by using products made from infected animals.

While mpox can cause mild illness and is rarely fatal, it can trigger painful symptoms. According to the CDC, symptoms of mpox include:

• Fever

• Headache

• Muscle aches and backache

• Swollen lymph nodes

• Chills

• Exhaustion

• Rash

The rash resembles pimples, blisters or sores and can appear on the face; inside the mouth; or on other parts of the body, including the hands, feet, chest, genitals and anus. Some people notice a rash one to three days after experiencing a fever, with other symptoms following. Others may only have a rash, which can take several weeks to heal and can lead to scarring.

The County of San Diego Health and Human Services Agency advises people who might have mpox to contact their doctor immediately. Although many people with mpox experience mild illness that will resolve on its own, others may be at high risk of severe illness and require treatment. This will likely include antiviral medications that have been approved to treat people with smallpox.

Those at greatest risk for severe illness or death due to mpox include people who:

• Have compromised immune systems

• Are younger than age 8

• Are pregnant or breastfeeding

• Have a history of skin conditions, such as eczema, burns, impetigo, herpes or severe acne

• Have one or more complications, including bacterial skin infection, gastroenteritis, pneumonia or other conditions

• Have mpox rash in the eyes, mouth or other areas of the body where infection might create a greater threat to health, including the genitals and anus

Regardless of the severity of the infection, it is important to cover the rash with clothing, wear a face mask around others, and avoid all close contact. Mpox is highly contagious and can spread until all sores have scabbed over, the scabs have fallen off, and a new layer of skin has formed over the areas of rash — a process that can take up to four weeks.

According to officers with the San Diego County Public Health Office, there is an mpox vaccine that is safe and effective at lowering the risk of getting mpox or the severity of symptoms if a person does get sick.

The vaccine, named Jynneos, is given as a two-dose injection and is available to people age 16 and older — or under age 16 with parental consent. The second dose is given 28 days after the first dose for maximum protection. Currently, booster doses are not recommended in those who have received both doses.

Two doses of the mpox vaccine or a previous clade II infection should protect against severe illness from clade I, the U.S. Department of Health and Human Services says.

County health officials recommend you should get the vaccine — both doses — if you:

• Are living with human immunodeficiency virus (HIV)

• Are a man or person assigned male at birth who has sex with men or people assigned male at birth

• Use or are eligible for HIV preexposure prophylaxis (PrEP)

• Are a sex worker

• Are the sexual partner of someone in the above groups

• Have had direct skin-to-skin contact with one or more people in a community where others have had mpox infection

• Have been diagnosed with a sexually transmitted disease (STD) in the past 3 months

• Are a close contact of someone who has mpox

• Work in settings, such as health care settings or laboratories, where you may be exposed to mpox

• Anticipate experiencing the above risks

Currently, there are no recommendations to receive the mpox vaccine if you plan to travel (unless you fall in one of the risk groups listed above).

Doses of the vaccine are available in San Diego through health care providers or public health clinics. Appointments can also be made on My Turn.

In addition to vaccination, the county recommends the following mpox prevention steps:

• Limit close contact — including sexual activity, kissing, cuddling or touching — with people who have sores or symptoms or who have been recently exposed to mpox.

• Avoid touching items or materials that someone with mpox has used or worn.

• Practice good hygiene and wash your hands with soap and water often.

If you are among those at greatest risk of mpox exposure, the CDC also recommends avoiding sexual activity until two weeks after your second vaccine dose; limiting the number of your sexual partners; and avoiding situations involving anonymous or multi-partner sex. The use of condoms alone cannot prevent exposure to mpox.