Understanding and Managing Mpox (Monkeypox)

Mpox is endemic to Africa, with most cases occurring in the Democratic Republic of the Congo where the virus was first identified in humans in 1970. Since 2016, cases in other African countries have been increasing, and as most cases occur in rural areas, the number is likely drastically underreported. Although there are many complex reasons for this increase, eradicating smallpox likely increased the number of mpox cases as it eliminated the virus's natural competition.

Mpox cases have sporadically occurred in other places. In 2003, rats imported from Ghana infected prairie dogs, spreading the virus around the American midwest, leading to more than 50 human cases. Cases of people traveling to Africa and getting infected were reported in 2018, 2019, and 2021. According to the World Health Organization, cases of mpox outside Africa, particularly in North America and Europe have [citation href="https://www.who.int/emergencies/situations/monkeypox-oubreak-2022" WHO" title="Mpox (monkeypox) outbreak" desc="Mpox (Monkeypox)"] outbreak spread significantly since May 2022 when infections in Nigeria set off an outbreak. In 2022, there were 30,000 cases in the U.S. alone. In 2023, this figure dropped to 1,700 cases, but the virus may be making a comeback.

There are two strains of mpox: one that circulates in the Congo basin and one that spreads in West Africa. The type that occurs in the Congo is more severe and is referred to as Clade I—up to 10% of infected individuals have died from this version of mpox. The 2022 outbreak involved the milder West African type of mpox, and 99% of infected individuals survived. It was dubbed Clade IIb. The virus mutates, and each clade can have subtypes. In May 2024, the CDC issued a warning about an outbreak of a deadlier subtype of mpox in the DRC known as Clade Ib, which emerged around September 2023.

Mpox primarily spreads through direct contact. In Congo, some cases come from contact with animals like squirrels, shrews, prairie dogs, and monkeys and are spread through scratches, bites, or eating contaminated game. Many of the deaths in Congo have been among children under 15, but kids in the U.S. would be less vulnerable as a result of lower exposure and generally better health. Exotic animals can pass the virus to house pets and owners.

Mpox can also spread from person to person through respiratory droplets and face-to-face interactions such as talking. Human-to-human transmission can occur from direct contact with body fluids or sheets, blankets, or clothes that come in contact with an infected person. Sexual transmission is a significant factor in the spread of the disease. The 2022 outbreak primarily affected men who have intercourse with men. In addition, infected pregnant individuals can pass mpox to the fetus.

Mpox has a long incubation period. It can take up to three weeks after exposure for symptoms to appear, though they can start in as little as four days. The first signs of infection are a general feeling of being unwell, followed by headaches, muscle aches, fever, swollen lymph nodes, and other flu-like symptoms. A few days later, a reddish rash forms and painful sores can appear over the next week or so. The rash usually appears on the face first, but if the person acquired the virus from sexual contact, it might begin on or near the genitals. The rash dries up after a week or two. Most mpox infections last between two and four weeks, and individuals are considered non-infectious when the sores have healed and scabs have fallen off. In severe cases, complications can include pneumonia, eye and skin infections, and confusion.

Mpox is generally rare, so healthcare professionals may first rule out other rash-producing infections like syphilis, chickenpox, and measles if the person does not live in an area with significant exposure risk. They may use blood tests or swabs from the rash to confirm a diagnosis. Some countries utilize tests that can only detect Clade I or Clade IIb, which can lead to missed diagnoses. The FDA has approved a test that can detect all versions of mpox but not the specific type in a particular individual. A positive result would necessitate further testing to clarify the clade.

No specific medication is approved for mpox. Treatment currently focuses on comfort and symptom management. People with active mpox infections should remain isolated, wear a mask, and cover lesions with gauze or bandages until healed. Scratching the lesions or shaving the area can spread the virus to other body parts or introduce new infection-causing bacteria. Acetaminophen can provide pain relief, and prescription mouthwashes may be necessary to treat pain if the rash appears in the mouth. Oral antihistamines can help with other symptoms.

Researchers are looking at investigational smallpox drugs like TPOXX as possible treatments for mpox, but these antivirals are currently only considered for people with severe cases and weakened immune systems.

The prognosis largely depends on the strain of the mpox virus that caused the infection, but even the more severe Clade 1 has a low mortality rate in the developed world. Most people recover from mpox within four weeks of when the symptoms appear, though they may be left with scarring and skin discoloration from the rash. Besides individuals with weakened immune systems, other segments of the population more vulnerable to a severe case of mpox include infants, people with a history of eczema, and people who are pregnant.

After shortages in 2022, vaccines for mpox are now commercially available, and the CDC recommends vaccination for anyone who is at higher risk of getting mpox or has had a recent exposure, including children. People who get vaccinated within four days of exposure may prevent the disease from developing, and getting vaccinated within 14 days of exposure can reduce the severity of the infection and the duration of the illness. Jynneos is a two-dose vaccine that is effective against all forms of the virus, but only a quarter of at-risk Americans received two doses by January 2023. The second dose is usually administered four weeks after the first dose, increasing protection.

The best way to prevent an mpox infection other than vaccination is to decrease contact with infected animals and limit person-to-person spread. Wash your hands frequently with soap and water, disinfect regularly touched surfaces, and avoid contact with clothing, bedding, and other materials that may be contaminated with the virus. Stay away from people who may be infected with mpox, and practice safe sex. In healthcare settings, people who care for patients infected with mpox should wear gloves, masks, and gowns, and patients may be kept in negative pressure rooms. People who have previously recovered from mpox do not require the vaccine.

Anyone can contract mpox if they are exposed to contaminated objects and surfaces or people and animals that have been infected. Most cases of mpox are not fatal and can be overcome without treatment, but those with compromised immune systems are particularly at risk of experiencing life-threatening symptoms. Vaccination is the best defense against the virus, but protective hygiene practices, safe sex, or curbed sexual activity can reduce the risk of infection. If you're unsure about your risk profile or what to do in the event of exposure, consult a healthcare professional.