What Is Mpox (Monkeypox)? Symptoms, Treatments and Prevention

Mpox is caused by the monkeypox virus, a relative of the smallpox virus. It is a zoonotic disease, meaning it can spread between animals and humans. In some cases, it can also spread from person to person through close or physical contact.

There are two main types (clades) of the mpox virus:

• Clade II — the strain behind most U.S. and global cases since 2022
• Clade I — a historically more severe strain, primarily seen in Central and East Africa

Until recently, all U.S. Clade I cases were linked to international travel. In October, the California Department of Public Health confirmed three Clade I mpox cases in Southern California with no recent travel history. Health officials are investigating these cases as the first possible local transmission in the U.S. but emphasize that the overall risk to the public remains low.

After exposure, mpox symptoms typically appear 3 to 17 days later (often around one or two weeks), though in some cases up to 21 days. During this incubation period, people usually feel well and are not believed to be contagious.

A rash is often the first and most noticeable sign of infection. It may appear on the hands, feet, chest, face, mouth or genital area and can range from mild to painful. The rash typically progresses from flat lesions to raised bumps, to fluid-filled blisters, then scabs over and heals, usually within two to four weeks.

The rash can look similar to sexually transmitted infections (STIs) like herpes or syphilis, especially when it appears on or near the genitals or anus. That’s why it’s important to watch for any new or unusual skin changes, especially after physical or intimate contact or recent travel.

“If you notice an unusual rash or skin lesions that start in one area, but quickly spread to others, particularly after possible exposure or travel, contact your health care provider,” Dr. Uejo says. “It may not be mpox, but it’s important to get evaluated.”

In addition to the rash, mpox may cause flu-like symptoms, including:

• Fever, chills and fatigue
• Headache and muscle aches
• Swollen lymph nodes, a key feature distinguishing mpox from smallpox
• Sore throat, nasal congestion or cough

Most people recover fully, but severe illness can occur, particularly with Clade I infections or in people with underlying health conditions. Seek immediate medical care if you experience:

• Difficulty breathing or chest pain
• Confusion, stiff neck or severe headache
• Seizures or loss of consciousness

Mpox can affect anyone. It is mainly spread through close, skin-to-skin or face-to-face contact with someone who is infected.

The virus is most contagious when a person has a rash, sores or scabs. Transmission often occurs during intimate contact, such as kissing, cuddling or sex. It can also spread while caring for someone who is ill.

Transmissions can spread through:

• Direct contact with an infected person’s rash, scabs or body fluids
• Intimate or sexual contact, including oral, anal or vaginal sex
• Touching or sharing clothing, bedding, towels or personal items used by someone with mpox
• Contact with infected animals, such as being scratched, bitten or handling animal products
• Prolonged face-to-face exposure to respiratory droplets (less common)

In rare cases, pregnant women can pass the virus to their fetus through the placenta.

While anyone can get mpox through close or physical contact, some people are more likely to develop severe illness or complications.

People at higher risk include those who:

• Have weakened immune systems, (such as people with living with uncontrolled HIV)
• Are young children (especially under age 8)
• Have eczema or other chronic skin conditions
• Are pregnant or breastfeeding

Recent outbreaks have mainly affected gay, bisexual and other men who have sex with men, especially those with multiple partners. However, mpox can affect anyone who has close contact with an infected person.

Most people recover on their own within two to four weeks. In most cases, rest, staying hydrated and keeping rash areas clean are enough to support healing. Over-the-counter pain relievers and fever reducers can help manage discomfort and reduce symptoms.

For more severe cases, or when lesions affect the eyes, mouth, throat or genitals, doctors in coordination with public health authorities may prescribe Tecovirimat (TPOXX). This antiviral is approved for treating smallpox and is available under an expanded access protocol for mpox.

Vaccination remains the most effective protection against mpox. The JYNNEOS vaccine, (approved by the Food and Drug Administration) is available through Medi-Cal, private insurance and public health programs for those who are uninsured or underinsured. Notably:

• The AIDS Drug Assistance Program (ADAP) for eligible Californians living with HIV or AIDS

• Pre-Exposure Prophylaxis Assistance Program (PrEP-AP)

Two doses are required for full protection. Boosters are not currently required for the general population, though recommendations may evolve.

In California, vaccine sites can be found through the state’s Vaccine Locator or local public health departments.

If you live in San Diego, check with the County Health & Human Services or your local pharmacy for availability.

You can reduce your risk of mpox infection by taking simple precautions:

• Avoid close or face-to-face contact with anyone who has a rash or flu-like symptoms
• Limit the number of sexual partners and avoid intimate contact if you or your partner feels ill
• Use condoms and gloves during sex (these reduce, but do not eliminate the risk of transmission)
• Wash your hands frequently with soap and water or use an alcohol-based sanitizer
• Do not share towels, bedding, toothbrushes or sex toys
• If caring for someone with mpox, wear a mask, gloves and gown, and avoid touching rashes or scabs
• Keep all lesions covered until fully healed

“If you can’t avoid contact with someone who has symptoms, try to prevent contact with contaminated materials,” Dr. Uejo says. “Practice good hand hygiene with frequent handwashing and wear a mask, gloves, and gown if close contact is necessary.”

If you test positive for mpox or suspect you may be infected, take steps to protect others:

• Stay home and isolate until all sores have scabbed and new skin has formed
• Inform close contacts and disinfect shared items, including bedding, clothing and surfaces
• Avoid intimate or physical contact until completely healed
• Consult your health care provider for treatment guidance and follow-up care

“If you suspect you have monkeypox, avoid close contact with others until a health care provider examines you,” Dr. Uejo advises. “If you test positive, isolate until you are fully healed.”