Mpox

Mpox is a disease caused by the mpox virus. The virus enters the body through broken skin, the respiratory tract or the mucous membranes (e.g., eyes, nose, or mouth).

Current situation

For information on the situation in Canada, refer to the Public Health Agency of Canada.

Prevention

Mpox is spread through close contact with a person with mpox, such as contact with their body fluids, mucus from the nose, saliva, or sores. Mpox can also be spread by sharing clothing, bedding or common items that have been in contact with the body fluids or sores of a person with mpox.

You can prevent spread of mpox by:

  • staying home and limiting contact with others if you have symptoms, or as recommended by your health care provider
  • avoiding close physical contact, including sexual contact, with someone who is infected with or may have been exposed to mpox
  • maintaining good hand hygiene and respiratory etiquette, including:
    • covering coughs and sneezes with the bend of your arm; and
    • wearing a well-fitting mask
  • cleaning and disinfecting high-touch surfaces and objects in your home, especially after having visitors

Signs and symptoms

Mpox is usually a mild illness and most people recover on their own after a few weeks. In rare situations people may become very sick, resulting in hospitalization and/or death.

People usually develop symptoms 5 to 21 days after being infected with the mpox virus. Symptoms usually occur in 2 stages and typically last from 2 to 4 weeks. In some cases, the rash can occur before other symptoms.

In stage 1, symptoms may include:

  • Fever
  • Chills
  • Swollen lymph nodes
  • Headache
  • Muscle pain
  • Joint pain
  • Back pain
  • Exhaustion

In stage 2 of the illness, a rash typically develops – usually within 1 to 3 days (sometimes longer) after the fever starts. The rash often starts on the face, arms, and/or legs, but can affect other parts of the body, such as the hands, feet, mouth and genitals.

The rash usually lasts between 14 to 28 days and changes through different stages before finally forming a scab which later falls off.

You can transmit the mpox virus from the first day of symptoms until the scabs have fallen off on their own and the skin is healed.

When to seek help

Contact your health care provider or 811 if you develop symptoms of mpox and/or if you have had contact with a person with known or suspected mpox.

Vaccination against mpox

If you are identified as a contact of someone that has mpox, a public health official may offer a vaccine called Imvamune. Imvamune can provide protection against smallpox viruses, including mpox. A public health official will discuss the use of Imvamune with you.

The virus can affect anyone through close person-to-person contact regardless of age, sex, gender or sexual orientation. To date, mpox has disproportionately affected some members of the 2SLGBTQIA+ communities.

Given the epidemiology of the outbreak in Canada, two doses of Imvamune administered at least 28 days (4 weeks) apart as a pre-exposure vaccination should be offered to:

  • Individuals 18 years of age or older who are two-spirit, non-binary, transgender, intersex or gender-queer, or cisgender individuals who are gay, bisexual, pansexual, and/or men who have sex with men AND meet at least one of the following criteria:
    • Have or are planning to have sex with one or more partners or are in a relationship where at least one of the partners may have other sexual partners
    • Have received a diagnosis of a sexually transmitted infection in the last year
    • Have attended, worked, or volunteered in sex-on-premises venues or may be planning to do so, whether in or outside of the province
    • Have had anonymous sex (e.g., using hookup apps) recently or may be planning to
    • Are a sexual contact of an individual who engages in sex work
  • Sexual partners 18 years of age and older of individuals who meet the above criteria
  • People 18 years of age and older who engage in, or plan to engage in, sex work regardless of gender, sex or sexual orientation
  • People 18 years of age and older who engage in sex tourism regardless of gender, sex or sexual orientation. Individuals planning to travel internationally should consult their healthcare provider on vaccination at least 4 to 6 weeks prior to travel particularly to countries with ongoing mpox transmission.
  • Based on available evidence that is limited for other immunocompromised populations, unvaccinated individuals with HIV-associated immunosuppression (e.g., CD4 count <200×10^6 cells/L) are considered at higher risk of severe mpox. Studies report that two doses of Imvamune are effective at preventing mpox and associated outcomes including among individuals living with HIV infection. Individuals living with HIV should discuss the Imvamune vaccine with their healthcare provider.

In general, more than two doses of Imvamune in the context of a routine immunization program is not recommended at this time due to lack of evidence on the risks and benefits. However, personnel working with replicating Orthopoxviruses in laboratory settings should be offered an additional dose after 2 years if they remain at risk of occupational exposure.

Evidence is limited for the pediatric population less than 18 years of age. Off-label use may be considered as pre- or post-exposure for those meeting the abovementioned criteria at their healthcare provider’s discretion.

Although there are limited data regarding Imvamune use among specific populations (e.g., immunocompromised due to disease or treatment; pregnancy or breastfeeding), these individuals should be offered Imvamune if vaccination is recommended based on high-risk criteria at the discretion of their healthcare provider.

It was previously recommended to wait a minimum of 4 weeks for Imvamune administration after or before an mRNA COVID-19 vaccine. Post-market safety surveillance data on Imvamune is now available, and shows the vaccine is well tolerated with no increased risk of myocarditis or anaphylaxis following vaccination, and no new or unexpected safety concerns were identified. Therefore, Imvamune vaccination can now be given concurrently (i.e., same day) or at any time before or after other live or non-live vaccines.

Preventative immunization for eligible people can be booked through Public Health Offices in your health zone. Please refer to the links below:

Central Zone

Eastern Urban/Rural Zones

Labrador-Grenfell Zone

Western Zone

Imvamune is also used as post-exposure vaccination to be administered to individuals who have had a high-risk exposure to a probable or confirmed case of mpox, or within a setting where transmission is happening. If you have been in contact with someone who has suspect or confirmed mpox, please contact your local Public Health Office.

Resources

For health professionals