Mpox virus

Overview

Mpox is a rare disease that is caused by infection with Mpox virus. The virus is related to the smallpox virus, but typically causes less serious disease. Most cases of mpox to-date have occurred in individuals living in Central and West Africa. In the past, limited cases had been identified in other countries but not in Canada.

Since May 2022, mpox cases have been identified in countries where the virus is not typically found. The Public Health Agency of Canada (PHAC) has now confirmed cases in Canada, including Alberta, but the risk to the general public is considered low.

Signs and symptoms

Mpox infection is usually a mild illness that resolves without treatment. Most people recover within several weeks, however severe illness can occur in some individuals.

Signs and symptoms can vary and do not always present in order. The illness may also not present the same in every case.

The risk for the general public, including children, is low. Children presenting with rash illness would not be considered to be at risk for mpox unless they have a known close contact exposure to a confirmed case, for example a household member. They should be investigated for more common causes of rash.

Symptoms

Symptoms can develop 5 to 21 days after exposure to the virus and generally begin with:

• fever
• chills
• swollen lymph nodes
• headache
• muscle pain
• joint pain
• back pain
• exhaustion

Rash

Within one to 3 days after the fever starts, a rash may start on the face and then spread elsewhere on the body. In some cases, the rash may occur without flu-like symptoms or flu-like symptoms may occur after the rash appears. The rash can affect:

• mucous membranes in the mouth, tongue and genital area
• palms of hands
• soles of the feet

The rash can last for 2 to 4 weeks and goes through different stages before the scabs fall off, from skin discoloration to sores to scabs.

Causes

Mpox is caused by infection with the Mpox virus. It does not spread easily between people, but may occur through:

• direct physical contact, including sexual contact, and contact with mpox
  skin lesions or scabs
• prolonged exposure to respiratory droplets of an individual infected with mpox
• contact with contaminated materials used by an infected person, such as clothing, bedding or towels

Mpox can spread to others from the time symptoms start until the scabs fall off and new skin can be seen, usually 2 to 4 weeks. Scabs contain virus that can spread the illness to others, and should be carefully disposed of.

Treatment and prevention

Most people recover from mpox without treatment. Some people with more serious illness may require hospitalization and supportive care.

Treatment

Treatment options may be available to those at risk of severe illness. Call HealthLink at 811 if you think you were exposed to a case of mpox.

• A limited supply of an antiviral drug is available for severe cases after specialist consultation.
• Imvamune is available in Alberta which provides some protection against mpox. If given shortly after exposure to mpox, it may prevent infection or reduce the severity of illness if infection does occur.

Prevention

To protect yourself and prevent mpox:

• avoid skin-to-skin or face-to-face contact with anyone who has symptoms
• minimize the number of sexual partners you have while the mpox outbreak is ongoing is the safest approach
• clean hands, objects and surfaces that have been touched regularly
• don’t share personal items with others
• wear a mask if you are in close proximity with someone who has symptoms

Vaccine eligibility

Pre-exposure

The Imvamune vaccine is available as a two-dose series, where eligible individuals can receive their second dose, 28 days after their first.

The following individuals are eligible for the Imvamune vaccine before exposure to mpox:

• individuals who self-identify as trans-gender, cis-gender, TwoSpirit, gender-queer, intersex, and non-binary and who also identify as gay, bisexual, or pansexual, and other men who have sex with men (MSM) community, and who meet at least one of the following criteria:
  • are planning to have, or in the past 90 days have had, 2 or more sexual partners
  • are planning to be, or in the past 90 days have been, in a relationship where at least one of the partners has other sexual partners
  • have received a diagnosis of a sexually transmitted infection within the last year
  • are planning to have, or in the past 90 days have engaged in sexual contact in sex-on-premises venues (for example bath houses, sex clubs), or who work or volunteer in these settings
• any sexual contacts of the individuals described above
• staff or volunteers in sex-on-premises venues where workers may have contact, or have had contact in the past 90 days, with potentially contaminated materials, without the use of personal protective equipment
• individuals who self-identify as sex workers regardless of gender identity or sexual orientation

Post-exposure

If given shortly after exposure to mpox, Imvamune vaccine may prevent infection or reduce the severity of illness if infection does occur. If you believe you have been in close prolonged contact with someone with mpox, self-isolate and call 811 or your primary care physician.

Book an appointment

Eligible individuals who are interested in receiving the mpox vaccine can call Health Link at 1-866-301-2668 to review eligibility and book an appointment.

International travel

Public Health Agency of Canada issued a level 2 travel health notice for mpox for affected countries.

Check for active advisories for your travel destination before you travel outside of Alberta or Canada.

Resources

Government of Alberta

• Mpox fact sheet

Alberta Health Services

• Mpox

Public Health Agency of Canada (PHAC)

• Mpox: Outbreak update
• Travel Advisory (December 15, 2022): Mpox

International

• US Centers for Disease Control and Prevention (CDC)
• World Health Organization (WHO)