Key points
- Regardless of clade, monkeypox can be spread, treated, and prevented the same way.
- Consider monkeypox as the cause of a diffuse or localized rash, particularly if there's recent travel to an outbreak area; evaluate any individual presenting with certain ulcers or rash for HIV and STIs.
- Conduct a thorough patient history, including detailed travel and sexual histories, to assess possible exposure to monkeypox.
- Provide patients with supportive care and pain control early in the illness.
- While there are no FDA-approved treatments specifically for monkeypox, people who have or are at risk for severe disease may benefit from additional care.
- Vaccine is approved and recommended for the prevention of monkeypox and can be used for post-exposure prophylaxis.
Overview
There are two types of the monkeypox virus (MPXV), clade I and clade II, each with two known subclades (Ia, Ib, IIa, IIb). Both clades and all subclades can be spread, treated, and prevented similarly. Historically, clade I MPXV was reported to have a much higher case-fatality rate than clade II MPXV; however, data from recent outbreaks suggest that the case-fatality rate for both clades is low, especially when optimal supportive care is provided.
Risk factors, affected populations, and locations of sustained transmission can differ between clades. A large outbreak of clade I MPXV began in 2024 and continues throughout Central and Eastern Africa. There also have been travel-associated clade I MPXV cases reported worldwide, including the United States. Community transmission has been identified in certain parts of Europe and the United States. A global clade II MPXV outbreak began in 2022, and cases continue to spread at low levels in many countries around the world.
MPXV is usually transmitted from person to person through close, sustained physical contact. In the clade I outbreak originating in Central Africa, transmission has occurred through sexual contact, day-to-day household contact, and in healthcare settings when PPE was not available. In the ongoing clade II MPXV outbreak, transmission has been almost exclusively associated with sexual contact
More information about each MPXV subclade
| Clade la | Clade lb | Clade Ila | Clade llb | |
|---|---|---|---|---|
| Geography | Endemic to Central Africa, including Republic of the Congo, Gabon, Democratic Republic of the Congo (DRC), Central African Republic, and southeastern Cameroon | Newly identified in the DRC with spread to nearby countries; travel-associated cases around the world | Endemic to West Africa, including northwestern Cameroon, Nigeria, Ghana, Cote d'Ivoire, Liberia, and Sierra Leone. | Endemic to West Africa (identified originally in Nigeria); spread to more than 100 non-endemic countries as part of the ongoing global outbreak that began in 2022 |
| Current Situation | Outbreak in Central Africa from 2023 to present | Outbreak in Central and Eastern Africa. There have been travel-associated cases in other parts of Africa, Asia, Europe, and North America, including the United States | Insufficient data | Caused the ongoing global monkeypox outbreak that began in 2022; still circulating globally at low levels, including in the United States |
| Population Primarily Affected in Outbreaks since 2022 | Both adults and children | Adults (often sex workers and their contacts); subsequent spread through day-to-day household contact | Both adults and children | Adults, particularly men who have sex with men in global outbreak |
| What's Known about How it's Spread | Primarily by contact with infected live or dead wild animals. Transmission can also occur via mother to fetus or close skin-to-skin contact, including intimate (e.g., massage, kissing) and sexual contact. | Primarily via close skin-to-skin contact, including intimate (e.g., massage, kissing) and sexual contact. Transmission can also occur via mother to fetus, or within households. | Primarily by contact with infected live or dead wild animals. Transmission can also occur via mother to fetus or close skin-to-skin contact, including intimate (e.g., massage, kissing) and sexual contact. | Primarily via close skin-to-skin contact, including intimate (e.g., massage, kissing) and sexual contact. Transmission can also occur via mother to fetus, or within households. Transmission to healthcare workers from sharps injuries and fomite transmission are rare but have been documented. |
| Mortality Rate | From more recent outbreaks, the mortality rate is ≤ 2.5%. Most deaths occur in people with immunocompromising conditions including children with malnutrition and other health conditions. | Mortality rate is less than 0.5% in Central and Eastern Africa. Most deaths occur in people with immunocompromising conditions. No mortality has been seen with travel associated cases outside Africa, but data are limited. | Mortality rate is around 1% but has limited data. Available data suggest lower CFR than clade I monkeypox | Mortality rate is less than 0.1%. Most deaths occur in people with immunocompromising conditions. |
| Vaccine | 2 doses of JYNNEOS vaccine; 1 dose of ACAM2000 for specific populations | |||
| Other Prevention Considerations | Avoid direct or skin-to-skin contact with people who have a rash that looks like monkeypox, including during sex or intimate contact; avoid objects or materials a person with monkeypox has used; avoid wild animals and animal products (lotions, bushmeat, etc.) in areas where monkeypox occurs regularly; wash hands regularly | |||
| Treatment | Healthcare professionals should assess pain in all patients with monkeypox and recognize that substantial pain may exist from mucosal lesions not evident on physical exam. Additional treatments may be needed for people at higher risk of severe disease. | |||
| Other Therapeutic Considerations | Most people recover with supportive care (nutritious food, fluids, antibiotics for secondary skin infections) and pain control (over-the-counter medications like acetaminophen and ibuprofen, topical steroids and anesthetics like lidocaine for local pain relief; prescription pain medications for short-term management of severe pain). | |||
Evaluating patients with suspected monkeypox
Patient history and physical examination
Clinicians should consider monkeypox when determining the cause of a diffuse or localized rash. Other diseases that can present similarly to monkeypox include herpes simplex virus (genital herpes), syphilis, herpes zoster (shingles), disseminated varicella-zoster virus infection, molluscum contagiosum, scabies, lymphogranuloma venereum, allergic skin rashes, and drug eruptions.
Clinicians should conduct a thorough patient history to assess possible monkeypox exposures or epidemiologic risk factors, including a detailed sexual history and travel history for any patient with suspected monkeypox.
Perform a complete physical examination, including a thorough skin and mucosal (e.g., oral, genital, anal) examination for the characteristic vesiculo-pustular rash of monkeypox. Clinicians may detect lesions of which the patient may be unaware, especially in the anogenital area.
Additional HIV/STI considerations for patients with suspected or confirmed monkeypox
In the ongoing clade II monkeypox outbreak, HIV infection and other STIs have been highly prevalent among people with monkeypox. Furthermore, people with HIV-associated immunocompromise are at risk for severe manifestations of monkeypox.
Evaluate any individual presenting with genital, anal, or perianal ulcers, proctitis, or diffuse rash for STIs per the CDC STI Treatment Guidelines.
All sexually active adults and adolescents in whom monkeypox is suspected should be evaluated for HIV and other STIs. Offer appropriate care to those with positive test results. The diagnosis of another STI does not exclude monkeypox as a concurrent infection may be present.
- Test for other STIs including syphilis, gonorrhea, and chlamydia in every sexually active adult and adolescent in whom monkeypox is suspected or confirmed.
- Test for HIV in every sexually active adult and adolescent in whom monkeypox is suspected or confirmed if current HIV status is unknown.
- Ensure those with HIV and with suspected or confirmed monkeypox are on effective antiretroviral therapy and linked to care to optimize immune function.
- Discuss and facilitate access to HIV pre-exposure prophylaxis (PrEP) for those who are HIV negative and at risk for HIV.
- Instruct patients with suspected monkeypox to follow isolation recommendations and avoid close contact with other people and with animals including pets until monkeypox has resolved.
CDC’s Sexually Transmitted Infections (STI) Treatment Guidelines provide current evidence-based prevention, diagnostic, and treatment recommendations for clinicians. Always assess patients based on your clinical circumstances and local disease burden.
Additional considerations for people at risk for severe monkeypox
Most people with monkeypox will recover within weeks with supportive care. Patients who are severely immunocompromised or have certain skin conditions are at particular risk of uncontrolled viral spread, which can cause severe manifestations of monkeypox and even be life-threatening. People who are at risk for severe monkeypox caused by either clade include those who:
- Are severely immunocompromised (e.g., those with HIV with CD4 <200, or solid organ transplant recipients)
- Have atopic dermatitis and other conditions affecting skin integrity
- Are children
- Are pregnant or breastfeeding
CDC has interim clinical guidance that may assist clinicians in managing patients with or who are at risk for severe monkeypox. Treatment for these patients involves Food and Drug Administration (FDA)–regulated drugs that are primarily stockpiled by the U.S. government for smallpox preparedness.
Prevention
Monkeypox vaccine
CDC routinely recommends vaccination for people with sexual risk factors who have not been diagnosed with monkeypox during the ongoing outbreak or have not already received 2 doses of the JYNNEOS vaccine. People at risk for monkeypox (regardless of clade) ideally should be vaccinated prior to exposure to MPXV.
People may receive MPXV post-exposure prophylaxis to help prevent monkeypox (post-exposure prophylaxis).
Two vaccines may be used for the prevention of monkeypox:
- JYNNEOS vaccine is FDA-approved and recommended by CDC and ACIP for the prevention of monkeypox and smallpox. It is available through the commercial supply chain.
- ACAM2000 vaccine is FDA-approved for immunization against smallpox and MPXV. In the United States, there is a large supply of ACAM2000, but this vaccine has more known side effects and contraindications.
The standard regimen for JYNNEOS involves a subcutaneous (SQ) route of administration with an injection volume of 0.5mL. An alternative regimen involving intradermal (ID) administration with an injection volume of 0.1mL may be used under an Emergency Use Authorization (EUA).
Both the standard (0.5mL SQ) and the alternative (0.1mL ID) regimen have been found to be effective for monkeypox prevention.
There is adequate supply of JYNNEOS vaccine. Therefore, clinicians can preferentially administer JYNNEOS via the subcutaneous route.
JYNNEOS vaccine is licensed as a series of two doses administered 28 days (4 weeks) apart.
People who are vaccinated should continue to take steps to protect themselves from infection by avoiding close, skin-to-skin contact, including intimate contact, with someone who has monkeypox.
Additional doses of vaccine
It’s not currently recommended for most people to have more than 2 doses of JYNNEOS vaccine. However, for those at occupational risk of exposure to orthopoxviruses (e.g., certain research laboratorians*), administration of additional doses is recommended at two- to 10-year intervals depending on the type of work being performed and vaccine used.
*Research laboratory personnel are those who directly handle cultures or animals contaminated or infected with monkeypox virus (MPXV). Vaccination is not routinely recommended for clinical laboratory personnel who perform routine chemistry, hematology, and urinalysis testing, including for patients with suspected or confirmed MPXV infection, healthcare personnel who care for patients with monkeypox or administer ACAM2000. Recommended infection prevention and control practices are effective in minimizing transmission. Vaccination can be offered based on site- and activity-specific biosafety risk assessments (e.g., identification of laboratory procedures with a high likelihood of generating aerosols or inadequate PPE availability).
MPXV testing
Obtain specimens for testing from accessible lesions, including those inside the mouth, anus, or vagina.
Patient management
Treatment
All patients with monkeypox may benefit from supportive care and pain control begun early in the illness. Monkeypox can commonly cause severe pain and can affect vulnerable anatomic sites, including the genitals and oropharynx, which can lead to other complications.
Assess pain in all patients with monkeypox and recognize that substantial pain may exist from mucosal lesions not evident on physical exam. Use topical and systemic strategies to manage pain. Pain management strategies should be patient-centered and tailored to the needs and context of an individual patient.
However, some patients experience severe manifestations of monkeypox. Consider additional monkeypox-directed treatment in people who have severe disease or risk factors for severe disease. Currently there is no FDA-approved treatment specifically for monkeypox; treatment involves Food and Drug Administration (FDA)–regulated medications that are primarily stockpiled by the U.S. government for smallpox preparedness.