Mpox virus (MPXV) is in the genus Orthopoxvirus and family Poxviridae
Epidemiology
Zoonotic disease endemic to west and central Africa
Hosts include non-human primates and prairie dogs, squirrels, and possibly other rodents
Endemic countries include DRC (most common), Liberia, Ivory Coast, Sierra Leone, Nigeria, Benin, Cameroon, Gabon, and South Sudan
Human infection is associated with animal trapping, hunting, and skinning, and other exposures to animals including bites, feces, urine, or respiratory droplets
Global outbreaks may happen with the global trafficking in exotic pets
Human-to-human transmission possible, but less than smallpox
Clinical Manifestations
Clinically indistinguishable from smallpox, though may have much more pronounced lymphadenopathy
Incubation period about 12 days (possibly up to 21 days)
Cidofovir 5 mg/kg IV once weekly for 2 weeks, possibly followed by same dose every other week
Brincidofovir 200 mg p.o. once weekly for 2 doses (i.e. day 1 and day 8)
Post-Exposure Prophylaxis
Can consider using a smallpox vaccine for adults with high risk contact of a confirmed of probable case
Risk assessment
High-risk contact:
Community / non-health care setting
Household member (e.g., family member, roommate) who lives with and shares indoor common spaces with the case.
Close, non-household exposure likely to result in unprotected direct contact to broken skin or mucous membranes including:
Intimate or sexual contact;
Providing direct physical care without appropriate personal protective equipment (PPE)
High risk environmental contact (e.g., cleaning potentially contaminated rooms without wearing appropriate PPE)
Health care setting (HCW is the contact)
Unprotected contact between an individual’s skin or mucous membranes or bodily fluids from a patient (e.g., accidental splashes of patient saliva to the eyes or oral cavity of a person, contact with patient without appropriate PPE), or contaminated materials (e.g., linens, clothing).
Being inside the patient’s room without appropriate PPE, during any procedures that may involve producing aerosols including from:
oral secretions (e.g., intubation),
skin lesions, or
re-suspension of dried fluids (e.g., shaking or changing of soiled linens)
Intermediate-risk contact:
Community settings: Does not meet high or low risk criteria, but interaction may result in an unprotected exposure to infectious materials (e.g., close, unprotected face-to-face contact, or intact skin-only direct contact).
Health-care settings:
Health care worker was in the patient care area with close, prolonged contact with an unmasked patient without wearing, at a minimum, a surgical/procedural mask.
Actions that result in contact between intact skin or sleeves or other parts of an individual’s clothing and the patient’s skin lesions, bodily fluids, or soiled linens (e.g., turning, bathing, or assisting with transfer) while not wearing appropriate PPE.
Low-risk contact:
Community settings: no direct physical contact, unlikely droplet exposure
Health-care settings:
Health care worker was in a patient room without wearing eye protection, regardless of duration of exposure
Health care worker wore gown, gloves, eye protection, and a surgical/procedural mask during all visits in the patient care area or room
Health care worker was in the patient care area with no close or prolonged contact with an unmasked patient without wearing, at a minimum, a surgical/procedural mask
No/very low-risk contact: An exposure deemed not meeting criteria for other risk categories (e.g., transient or brief community interactions that did not involve close or prolonged contact, or risk of direct contact with an infectious lesion)
PEP is recommended for high-risk exposures, can be considered for intermediate-risk exposures, and is not recommended for low-/very low-/no-risk exposures
PEP is with Imvamune vaccine
Accessed through the Public Health units (in Ontario), at EOCoperations.MOH@ontario.ca or 1-866-212-2272
References
^Emily A Siegrist, Joseph Sassine. Antivirals With Activity Against Mpox: A Clinically Oriented Review. Clinical Infectious Diseases. 2022;76(1):155-164. doi:10.1093/cid/ciac622.