Mpox in 2023: Information for clinicians

Advisory Alert

March 20, 2023

*Cette information est seulement disponible en anglais.

To: Local Health System Partners


There have been several new cases of mpox reported in Ontario over the last several weeks. No epidemiological links between cases have been identified and no cases have reported international travel.

This Advisory Alert summarizes the Ministry of Health’s recent guidance document titled, Mpox in 2023: Information for clinicians. Key highlights related to mpox epidemiology, clinical presentation, and treatment, as well as considerations for immunization are included below.


The main route of mpox transmission is direct close contact (skin-to-skin), particularly through sexual contact. Other routes of transmission, including respiratory transmission and close but not-direct contact have not been observed in Ontario.

Mpox has mainly, but not exclusively, affected gay, bisexual, and men who have sex with men (gbMSM) who have more than one, new and/or anonymous sexual partners. There have been no cases of mpox reported in children in Canada and only a few cases among cis-gender women.

Clinical Presentation & Testing

Mpox has a broad range of clinical presentations with common symptoms including:

Emerging evidence suggests that the clinical presentation of mpox in vaccinated individuals may be more mild or subclinical.

In the at-risk groups mentioned above, testing for mpox should be conducted with compatible symptoms and consideration for screening and testing for other STIs. Specimens should be taken of skin lesions in patients with a rash, and rectal swabs for those with rectal pain/lesions. In risk groups presenting with skin lesions, depending on clinical presentation, diagnostic tests should include mpox in addition to testing for syphilis, HSV, and VZV. Nasopharyngeal (NP) swabs can be used when a patient does not have a rash but does present with other compatible signs and symptoms.


The anti-viral tecovirimat (TPoxx®) is available for mpox patients at risk of (i.e. severely immunocompromised) or experiencing severe disease.

To request TPoxx® contact the Ministry of Health Emergency Operations Centre (MEOC) at or by calling the Healthcare Provider Hotline at 1.866.212.2272.


Imvamune® is a live, attenuated, non-replicating vaccine that is approved in Canada for protection against mpox. Imvamune® is a two-dose series, with a minimum interval of 28 days between doses.

As of the end of February 2023, less than 20 percent of people in Ontario who received a first dose of Imvamune® had received a second dose of the vaccine. It should be noted that delays between doses does not indicate that the series needs to be reinitiated. Please reach out to any of your clients who are eligible for a second dose and have not yet received one. This is especially important given the current epidemiological risk and the fact that second doses were not originally available so many at-risk individuals may not be aware that a second dose is required.

Eligibility for Imvamune® for pre-exposure vaccination in Ontario is as follows:

Eligible individuals seeking pre-exposure vaccination should be directed to call Public Health at 705.522.9200, ext. 482 (toll-free 1.866.522.9200) or Réseau ACCESS Network at 705.688.0500. Individuals can also call Public Health at ext. 772 if they are seeking post-exposure vaccination.


Original Signed By

Dr. Imran Adrian Khan

Public Health Physician and Director of Sexual Health, Vaccine Preventable Diseases and COVID-19 Vaccination Division

Public Health Sudbury & Districts


NOTE: All Advisory Alerts are found on our website.

This item was last modified on March 21, 2023