Monkeypox

Last updated: August 25, 2022

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Monkeypox is an infectious disease caused by the Monkeypox virus of the Orthopoxvirus genus. It is endemic in West and Central Africa. In 2022, monkeypox spread to nonendemic regions and was declared a public health emergency of international concern by the WHO. Monkeypox is primarily transmitted via skin-to-skin contact with lesions from an infected individual or from a bite or scratch from an infected animal. Clinical features include flu-like symptoms, lymphadenopathy, and a painful, vesicular rash that typically develops 1–4 days after the onset of fever. Diagnosis is confirmed by PCR from a sample of the lesion. Affected individuals generally recover within 2–4 weeks with supportive treatment. Individuals with severe disease may be treated with antivirals. Two vaccines are currently available for use against monkeypox.

  • Endemic in West and Central Africa [1]
  • Travel-associated outbreak in the UK in May 2022, with subsequent cases in continental Europe, North America, South America, and Australia [2]
  • On July 23, 2022, the WHO declared the monkeypox outbreak a public health emergency of international concern. [3]

Epidemiological data refers to the US, unless otherwise specified.

Diseases with a similar blistering appearance such as chickenpox and smallpox typically do not cause lymphadenopathy.

Perform a thorough clinical evaluation and obtain PCR testing if indicated.

While PCR testing alone is required to diagnose monkeypox, additional laboratory studies (e.g., CBC, CMP) can identify individuals with severe disease who have indications for inpatient management and/or antiviral therapy.

PCR testing [8][9][10]

Indications

  • Characteristic monkeypox rash
  • OR clinical suspicion and the presence of one or more of the following within 21 days of symptom onset:
    • Close or intimate contact with someone who has:
    • Travel to a country with monkeypox cases or to an endemic region
    • Contact with animals, or products derived from animals, known to carry monkeypox

Procedure

Contact the local or state health department for further guidance on testing.

  • Isolate patients during evaluation.
  • Obtain two separate swabs from multiple lesions (if present).
  • Do not unroof lesions prior to swabbing.
  • Send samples for nonvariola Orthopoxvirus PCR test.

Advise patients to remain isolated while awaiting test results, which may take 2–3 days.

The differential diagnoses listed here are not exhaustive.

Approach [7][9][10]

Severity assessment [7][9]

Infection control [7][9]

Isolation recommendations may vary regionally and may change as the mechanisms of the spread of monkeypox infection are better understood.

Advise patients to avoid the following until all lesions have healed: close contact with people and animals, using contact lenses, shaving skin with lesions, and sharing household or personal items.

Patients are contagious until crusts have fallen off and new skin has formed.

Pharmacotherapy [9]

The following therapies can be used off-label under expanded access (compassionate use) protocols.

Supportive care [7][9]

We list the most important complications. The selection is not exhaustive.

  • Affected individuals typically recover within 2–4 weeks. [1]
  • Mortality: 1–10% (esp. children and immunocompromised individuals)

Primary prevention [9][11]

Two live Vaccinia virus vaccines are available.

Secondary prevention [9]

  • Monitoring: for clinical features of monkeypox
    • Indication: all patients with any known monkeypox exposure
    • Duration: 21 days
    • Activity restrictions are not required during monitoring.
    • If symptoms develop, isolate until evaluation by a health care provider.
  • Postexposure prophylaxis
    • Vaccination
      • Indication: prolonged, close contact of lesions, body fluids, or fomites in an infected individual and mucus membranes or broken skill in an exposed individual
      • Preventive if administered within 4 days of exposure
    • Ring vaccination has been considered for use in the 2022 monkeypox outbreaks in different parts of the world.
    • Vaccinia immune globulin: for individuals with severe T-cell immunodeficiency in whom vaccination is contraindicated
  1. Monkeypox. https://www.who.int/news-room/fact-sheets/detail/monkeypox. Updated: May 19, 2022. Accessed: June 22, 2022.
  2. Multi-country monkeypox outbreak in non-endemic countries. https://www.who.int/emergencies/disease-outbreak-news/item/2022-DON388. Updated: May 29, 2022. Accessed: May 30, 2022.
  3. WHO Director-General declares the ongoing monkeypox outbreak a Public Health Emergency of International Concern. https://www.who.int/europe/news/item/23-07-2022-who-director-general-declares-the-ongoing-monkeypox-outbreak-a-public-health-event-of-international-concern. Updated: July 23, 2022. Accessed: August 2, 2022.
  4. Clinical management and infection prevention and control for monkeypox: Interim rapid response guidance. https://www.who.int/publications/i/item/WHO-MPX-Clinical-and-IPC-2022.1. Updated: June 10, 2022. Accessed: August 1, 2022.
  5. del Rio C, Malani PN. Update on the Monkeypox Outbreak. JAMA. 2022 . doi: 10.1001/jama.2022.14857 . | Open in Read by QxMD
  6. Monkeypox. https://www.cdc.gov/poxvirus/monkeypox/about.html. Updated: July 22, 2022. Accessed: August 16, 2022.
  7. Guarner J, del Rio C, Malani PN. Monkeypox in 2022—What Clinicians Need to Know. JAMA. 2022; 328 (2): p.139. doi: 10.1001/jama.2022.10802 . | Open in Read by QxMD
  8. Monkeypox and Smallpox Vaccine Guidance. https://web.archive.org/web/20220901192437/https://www.cdc.gov/poxvirus/monkeypox/clinicians/smallpox-vaccine.html. Updated: December 2, 2019. Accessed: May 23, 2022.
  9. Monkeypox: experts give virus variants new names. https://www.who.int/news/item/12-08-2022-monkeypox--experts-give-virus-variants-new-names. Updated: August 12, 2022. Accessed: August 24, 2022.
  10. Rimoin AW, Mulembakani PM, Johnston SC, et al. Major increase in human monkeypox incidence 30 years after smallpox vaccination campaigns cease in the Democratic Republic of Congo. Proceedings of the National Academy of Sciences. 2010; 107 (37): p.16262-16267. doi: 10.1073/pnas.1005769107 . | Open in Read by QxMD
  11. Thornhill JP, Barkati S, Walmsley S, et al. Monkeypox Virus Infection in Humans across 16 Countries — April–June 2022. N Engl J Med. 2022 . doi: 10.1056/nejmoa2207323 . | Open in Read by QxMD

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