Mpox, formerly known as monkeypox, is a viral disease caused by the monkeypox virus. This virus belongs to the Orthopoxvirus genus, and within it, there are two main types, or clades: clade I and clade II. A specific type of clade II, known as clade IIb, was responsible for the global mpox outbreak in 2022 and 2023. Even today, mpox remains a concern, especially with recent increases in cases in places like the Democratic Republic of Congo caused by clade I viruses. Fortunately, vaccines are available and are a key part of public health strategies to manage and prevent mpox.
Mpox Overview: What You Need to Know
Mpox is an infectious illness characterized by a painful rash, swollen lymph nodes, fever, headache, muscle aches, back pain, and fatigue. While most individuals recover fully, mpox can be severe in some cases.
The culprit behind mpox is the monkeypox virus (MPXV). This virus is a double-stranded DNA virus encased in a protective envelope. It’s part of the Orthopoxvirus genus, which also includes viruses like variola (the cause of smallpox), cowpox, and vaccinia. As mentioned, mpox viruses are classified into two main clades: clade I and clade II, each with further subdivisions.
The global outbreak starting in 2022 was driven by clade IIb, and this outbreak is still ongoing in various parts of the world, including some African nations. Simultaneously, outbreaks of clades Ia and Ib are growing, particularly in the Democratic Republic of the Congo and other African countries. Notably, by August 2024, clade Ib had also been detected outside of Africa.
While the natural source of the mpox virus remains unknown, research suggests various small mammals, such as squirrels and monkeys, can be infected with it.
How Does Mpox Spread? Understanding Transmission
Mpox primarily spreads from person to person through close contact with someone who has the virus. This close contact can occur in several ways:
- Skin-to-skin contact: This includes touching and sexual contact.
- Mouth-to-mouth or mouth-to-skin contact: Activities like kissing can transmit the virus.
- Face-to-face contact: Being in close proximity, such as talking or breathing near someone with mpox, can spread infectious respiratory particles.
Individuals with multiple sexual partners have a higher risk of contracting mpox due to the increased likelihood of close contact.
Transmission can also happen through contact with contaminated materials. This includes items like:
- Clothing and linens: Sharing bedding or clothes with an infected person can spread the virus.
- Needle stick injuries: Healthcare workers and individuals in settings like tattoo parlors are at risk from contaminated needles.
Vertical transmission, from parent to child, is also possible:
- During pregnancy or birth: The virus can pass from a pregnant person to the fetus or newborn. Mpox infection during pregnancy can lead to serious complications, including pregnancy loss, stillbirth, newborn death, or health issues for the parent.
Animal-to-human transmission can occur through:
- Bites or scratches from infected animals.
- Handling infected animals during activities like hunting, skinning, trapping, cooking, or playing with carcasses.
- Eating infected animals.
The specific animal species that naturally carry the mpox virus are still under investigation. Ongoing research aims to better understand mpox transmission in different situations and environments.
Recognizing Mpox: Signs and Symptoms
Mpox symptoms typically appear within one week of exposure, but can range from 1 to 21 days. Symptoms usually last for 2 to 4 weeks, although they may persist longer in individuals with weakened immune systems.
Common mpox symptoms include:
- Rash: This is a hallmark symptom of mpox.
- Fever
- Sore throat
- Headache
- Muscle aches
- Back pain
- Low energy
- Swollen lymph nodes
For some, the rash is the first noticeable symptom, while others may initially experience fever, muscle aches, or sore throat.
The mpox rash often starts on the face and then spreads to other parts of the body, including the palms of the hands and soles of the feet. It can also appear in areas of initial contact, such as the genitals. The rash evolves through stages: starting as flat spots, developing into fluid-filled blisters that can be itchy or painful. As the rash heals, the blisters dry up, crust over, and eventually fall off.
The number of lesions varies significantly, from just a few to hundreds. These lesions can appear on:
- Palms and soles
- Face, mouth, and throat
- Groin and genital areas
- Anus
Some individuals also experience painful rectal swelling (proctitis), pain during urination (dysuria), or difficulty swallowing.
People with mpox are contagious until all lesions have healed and new skin has formed. It’s also possible to be infected with mpox and not show any symptoms (asymptomatic infection). While transmission from asymptomatic individuals has been reported, it’s not yet fully understood how common this is.
Certain populations are at higher risk for severe mpox illness, including:
- Children
- Pregnant individuals
- People with weakened immune systems, such as those with poorly controlled HIV.
Serious complications from mpox can include:
- Secondary bacterial infections of the skin, leading to abscesses or significant skin damage.
- Pneumonia
- Corneal infection, which can result in vision loss.
- Pain or difficulty swallowing
- Dehydration or malnutrition due to vomiting and diarrhea.
- Infections of the blood (sepsis), brain (encephalitis), heart (myocarditis), rectum (proctitis), genital organs (balanitis), or urinary passages (urethritis).
In some cases, mpox can be fatal.
Mpox Diagnosis: Getting Tested
Diagnosing mpox can be challenging as its symptoms can resemble other infections and conditions. It’s crucial to differentiate mpox from:
- Chickenpox
- Measles
- Bacterial skin infections
- Scabies
- Herpes
- Syphilis
- Other sexually transmitted infections
- Medication-related allergies
It’s also possible for someone with mpox to have another infection simultaneously, like syphilis or herpes. In children, mpox may be mistaken for chickenpox. Therefore, testing is essential for early diagnosis, proper care, and preventing further spread.
The primary lab test for mpox is PCR (polymerase chain reaction) testing, which detects viral DNA. The best samples for testing are collected directly from the rash – skin, fluid, or crusts – using a vigorous swab. If skin lesions are not present, throat or anal swabs can be used. Blood tests are not typically recommended. Antibody tests are not useful for diagnosing mpox as they cannot distinguish between different orthopoxviruses.
HIV testing is recommended for adults diagnosed with mpox, and for children as appropriate. Testing for other conditions, such as varicella-zoster virus (VZV), syphilis, and herpes, should also be considered when feasible.
Mpox Treatment and Vaccination: Management and Prevention
Mpox treatment focuses on managing symptoms, caring for the rash, alleviating pain, and preventing complications. Early and supportive care is key to managing mpox effectively.
Vaccination is a powerful tool for mpox prevention. Mpox vaccines can be used for:
-
Pre-exposure prophylaxis (PrEP): Vaccination before exposure to prevent infection. This is recommended for individuals at high risk of mpox, especially during outbreaks.
High-risk groups for mpox vaccination include:
- Healthcare workers who may be exposed to mpox.
- Household contacts and close community members of people with mpox, including children.
- Individuals with multiple sexual partners, including men who have sex with men.
- Sex workers of any gender and their clients.
-
Post-exposure prophylaxis (PEP): Vaccination after exposure to prevent or lessen the severity of infection. For PEP to be most effective, the vaccine should be given within 4 days of contact with someone with mpox. Vaccination up to 14 days after exposure may still be beneficial if symptoms haven’t developed.
While some antiviral medications have been authorized for emergency use in certain countries and are being studied in clinical trials, there is currently no proven antiviral treatment specifically for mpox. Research continues to evaluate potential antiviral therapies, and optimizing supportive care remains a priority.
Individuals with both HIV and mpox should continue their antiretroviral therapy (ART). For those newly diagnosed with HIV, ART should be started within 7 days of the HIV diagnosis.
Mpox Self-Care and Prevention: What You Can Do
Most people with mpox recover fully within 2 to 4 weeks. To manage symptoms and prevent spreading mpox to others, follow these recommendations:
Do:
- Contact your healthcare provider for guidance.
- Stay home and, if possible, isolate in a well-ventilated room.
- Wash your hands frequently with soap and water or use hand sanitizer, especially after touching sores.
- Wear a mask and cover lesions when around others until the rash has healed.
- Keep skin dry and uncovered (unless you are in a shared room with someone).
- Avoid touching shared items and disinfect shared spaces regularly.
- Use saltwater rinses for mouth sores.
- Take warm baths with baking soda or Epsom salts for body sores.
- Use over-the-counter pain relievers like acetaminophen (paracetamol) or ibuprofen for pain.
Do not:
- Pop blisters or scratch sores: This can slow healing, spread the rash, and increase the risk of infection.
- Shave areas with sores until scabs are healed and new skin has formed, as shaving can spread the rash.
To prevent mpox from spreading to others, individuals with mpox should:
- Isolate at home or in a hospital as directed by their healthcare provider for the entire infectious period – from symptom onset until all lesions have healed and scabs have fallen off.
- Cover lesions and wear a well-fitting mask when around others.
- Use condoms during sex to reduce the risk of mpox transmission, but be aware that condoms do not prevent skin-to-skin or mouth-to-skin transmission. It is recommended to use condoms as a precaution for 12 weeks (about 3 months) after recovery.
Taking a break from sexual activity with new partners during periods of increased mpox transmission can also reduce risk. Individuals who have been in contact with someone with mpox should monitor for symptoms for 21 days (3 weeks) and avoid sexual activity during this time.
Healthcare workers should adhere to strict infection prevention and control measures when caring for patients with mpox, including using appropriate personal protective equipment (PPE) such as gloves, gowns, eye protection, and respirators, and following protocols for safe specimen collection and handling sharps.
Mpox Outbreaks: A History and Current Situation
The monkeypox virus was first discovered in 1958 in monkeys in Denmark used for research. The first human case of mpox was reported in 1970 in a nine-month-old boy in the Democratic Republic of the Congo. Following the eradication of smallpox in 1980 and the subsequent cessation of smallpox vaccination, mpox gradually emerged in central, east, and west Africa. Since then, mpox has been reported sporadically in central and east Africa (clade I) and west Africa (clade II). In 2003, an outbreak in the United States was linked to imported wild animals (clade II). Since 2005, the Democratic Republic of the Congo has reported thousands of cases annually. In 2017, mpox re-emerged in Nigeria and has continued to spread within the country and to travelers abroad.
Data on suspected and confirmed cases up to 2021 are available here and data on laboratory confirmed cases from 2022 to the present are available here.
In May 2022, a significant mpox outbreak began and rapidly spread across Europe, the Americas, and all six WHO regions. This global outbreak disproportionately affected gay, bisexual, and other men who have sex with men, spreading primarily through sexual networks. More information on the global outbreak can be found here, including resources on community responses to control the outbreak here.
In 2022, clade I mpox outbreaks occurred in refugee camps in the Republic of Sudan.
Since 2022, the Democratic Republic of the Congo has experienced a surge in mpox cases and deaths. A new variant of clade I, called clade Ib, has emerged and is spreading person-to-person in some areas. As of mid-2024, clade Ib has also been reported in other countries beyond Africa.
Between January 2022 and August 2024, over 120 countries have reported mpox, with more than 100,000 laboratory-confirmed cases and over 220 deaths among confirmed cases.
Stigma and Discrimination: Addressing Harmful Barriers
Stigma and discrimination related to any disease are unacceptable. Mpox-related stigma can hinder public health efforts and prolong outbreaks by making people hesitant to seek care and treatment. Unfortunately, stigma, discrimination, and racism related to mpox have disproportionately affected communities initially most impacted by the disease, particularly men who have sex with men, transgender people, and gender-diverse communities.
WHO Response: Global Efforts Against Mpox
The World Health Organization (WHO) is working with member states and partners to prevent and respond to mpox outbreaks. This includes:
- Coordinating research on vaccines and treatments.
- Strengthening national health systems.
- Facilitating equitable access to vaccines, therapeutics, diagnostics, and other essential tools.
The WHO Director-General, Dr. Tedros Adhanom Ghebreyesus, has declared mpox a Public Health Emergency of International Concern (PHEIC) twice: first in May 2022 and again in August 2024.
