SUMMARY:

Monkeypox is a zoonosis (a disease that is transmitted from animals to humans). However, human-to-human cases have been reported and occur through contact with bodily fluids, lesions on the skin or on internal mucosal surfaces, such as in the mouth or throat, respiratory droplets and contaminated objects.

MONKEYPOX: GENERAL CONSIDERATIONS

Signs and Symptoms

• Incubation period: 3 to 17 days
• Prodromal period (initial symptoms)
  • Fever
  • Headache
  • Muscle aches
  • Backache
  • Swollen lymph nodes
  • Chills
  • Exhaustion
  • Note: above symptoms may not occur, or may follow rash development

• Within 1 to 3 days (sometimes longer) following fever
  • Rash beginning on the face then spreading to other parts of the body
  • Lesions often occur in the genital and anorectal areas or in the mouth.
  • Rash is not always disseminated across many sites on the body.
  • Rash may be confined to only a few lesions or only a single lesion.
  • Rash does not always appear on palms and soles.
  •  
• Lesions
  • Well circumscribed, deep seated, and often develop umbilication (resembles a dot on the top of the lesion)
  • Are of similar size and stage of development on a single site of the body (ex: pustules on face or vesicles on legs)
  • Disseminated rash is centrifugal (more lesions on extremities, face)
  • Described initially as painful, then itchy while healing
• Lesions progression prior to falling off
  • Macules
  • Papules
  • Vesicles
  • Pustules
  • Scabs followed by resolution

• Illness duration
  • 2 to 4 weeks
• Testing
  • Follow CDC guidelines on infection prevention and control guidelines for suspected cases (see primary resources)
  • PCR is the preferred laboratory test for monkeypox
  • Best diagnostic specimens are directly from the rash
    • Skin | Fluid or crusts | Biopsy where feasible
  • Antigen and antibody detection methods may not be useful as they do not distinguish between orthopoxviruses

Note: After investigating cases of false-positive monkeypox test results, the CDC now recommends retesting low-risk individuals who test positive with low amounts of virus detected | Consider alternative diagnoses such as hand, foot, and mouth disease; varicella; or molluscum contagiosum

Mortality

• In Africa, monkeypox has been shown to cause death in as many as 1 in 10 persons who contract the disease
• Severity is dependent on health of the individual, the route of exposure, and the strain of the infecting virus

Treatment

• There is no treatment specifically for monkeypox
• Some drugs developed for smallpox may be used to treat monkeypox infections due to the genetic similarity between the two viruses
  • Antiviral: Tecovirimat (TPOXX)
  • For severe disease: Hemorrhagic | Large number of confluent lesions | Severe necrotizing or obstructing lymphadenopathy | Sepsis | myocarditis | disease requiring hospitalization | Infection of areas at high risk for strictures
  • Consider treatment for patients at high risk for severe disease: Immunocompromised | Pediatric | Pregnant | Breastfeeding | Conditions affecting skin integrity
  • For high-risk patients
• Most patients recover fully within 2 to 4 weeks without treatment
• Patients with monkeypox should follow CDC guidelines on Isolation

Vaccines

• Recommended for people who have been in contact with someone with monkeypox
  • Have had multiple sexual partners in the past 2 weeks in an area with known monkeypox infections
  • Have jobs that may expose them to orthopoxviruses
• The preferred vaccine against monkeypox is JYNNEOS, a 2-dose vaccine
  • Immune protection is maximized 14 days after the second vaccine dose
• An alternative vaccine to JYNNEOS may be ACAM2000, a single-dose vaccine
  • Immune protection is maximized 4 weeks after dose
  • Has potential for more side effects and adverse events than JYNNEOS

KEY POINTS:

• Diagnostic specifiers include: (Please see CDC Image Gallery in ‘Learn More – Primary Sources’ below for more on lesion identification)
  • Prodromal symptoms may or may not precede rash and can follow rash
• PCR of diagnostic specimen from the rash is the preferred laboratory test for monkeypox
• Most cases resolve in 2-4 weeks without need for treatment
• Some antiviral drugs developed for smallpox, such as tecovirimat (TPOXX), may be used to treat severe monkeypox infections
• Vaccination is recommended for those exposed to monkeypox and/or at high risk of contracting monkeypox
  • The preferred vaccine is JYNNEOS, a 2-dose vaccine
• Physicians and patients should follow CDC guidelines for Infection Prevention

Learn More – Primary Sources:

General Resources Including Lesion Images

• CDC: Monkeypox
• CDC: Monkeypox information specifically for healthcare professionals
• CDC (includes IMAGE GALLERY): Clinical Recognition | Monkeypox
• JAMA: Monkeypox in 2022—What Clinicians Need to Know
• CDC: Guidance for Tecovirimat Use Under Expanded Access Investigational New Drug Protocol during 2022 U.S. Monkeypox Cases
• AMA: New CPT Codes for Monkeypox
• Identifying False-Positive Monkeypox Results