Mpox (formerly known as monkeypox) Information for Physicians

Reporting a case of mpox

Effective June 16, 2022, mpox has been designated a Disease of Public Health Significance (DOPHS) as “Smallpox and other Orthopoxviruses including Mpox” under the Health Protection and Promotion Act (HPPA).

Persons required to report DOPHS and/or communicable diseases under the HPPA are now required to report directly to the local Medical Officer of Health in accordance with the reporting requirements in the Act, as per routine disease processes.

Suspect, probable, and confirmed cases of mpox must be reported immediately to Halton Region Public Health by calling 905-825-6000, ext. 7341 during regular business hours and 311 after hours.

Testing for mpox

• Laboratory testing is helpful for reporting and case/contact management purposes for any individual with rash/symptoms similar to mpox, either testing for mpox and/or other infections on the differential diagnosis.
• Testing for mpox can be done by primary care providers with the specimen having the same transport requirements (i.e. category B) as other microbiology specimens such as a swab collected for gonorrhoea, blood collected for syphilis, urine for routine culture and susceptibility.
• The outer packaging (bag) must be labelled certified for UN3373 and must be marked on a contrasting background with “TU 0886 Temporary Certificate”.
• All specimens from a patient being investigated for mpox, including specimens submitted for other tests, should indicate on the requisition that this patient is suspected of having mpox.
• All specimens from a patient being investigated for mpox are considered dangerous goods and as such, appropriate training is required for the handling, offering for transport, or transport of the specimens. For more information on training, refer to guidance from Temporary Certificate TU 0886 (external link).
• Detailed information on testing, specimen collection and specimen transport is available on PHO Lab website (external link).

What is mpox?

Mpox (formerly known as monkeypox) is an infectious disease that is caused by the monkeypox virus. The virus that causes mpox has two known subtypes, clade I and clade II.

• Clade I: Sub-clade Ia is endemic to Central Africa and causes more severe illness and deaths than clade II. Sub-clade Ib emerged in the Democratic Republic of Congo (DRC) in 2023 and is spreading through direct contact
• Clade II: This clade is endemic to West Africa and is associated with less severe illness and deaths than clade I. Sub-clade IIb was responsible for the 2022 global mpox outbreak
• The current subtype of mpox with cases in Ontario and Canada is clade II.

Early symptoms of mpox may include:

• rash
• headache
• fever
• chills
• sweats
• swollen lymph nodes
• muscle pain
• fatigue
• sore throat

Symptoms that usually appear 1 to 3 days later are:

• rash or sores on the palms of the hands or on the soles of the feet
• rash or sores inside the mouth
• rash or sores on the genitals or inside or around the anus or rectum
• pain or bleeding from the anus or rectum

The incubation period can range from 3 to 21 days. Mpox illness is usually self-resolving within a period of 2 to 4 weeks. The spectrum of severity varies from a single skin lesion to disseminated, multi-organ infection. At this time, it is not known with certainty if asymptomatic infections occur.

Infection Control Practices for mpox

For up to date recommendations, please see IPAC Recommendations for Mpox in Health Care Settings (external PDF).

What should a patient do if they have symptoms of mpox?

If a patient has symptoms of mpox they should call their health care provider. If contact with others is mandatory (e.g., seeking health care), patient should wear a high-quality medical mask and cover up all lesions.

In general, self-isolation is not required if cases can adhere to risk mitigation measures (see Risk Mitigation measures below)

• Cases presenting with skin lesions that can be covered and those with no or mild systemic symptoms that can adhere to risk mitigation measures are not required to self-isolate.
• Cases presenting with eruptions of skin lesions that cannot be covered and/or have systemic symptoms that make adherence to risk mitigation measures difficult (e.g. unable to wear a medical mask) should self-isolate.
• Cases who initially present with mild symptoms but go on to develop symptoms that make adherence to risk mitigation measures difficult should self-isolate (e.g., numerous skin lesions that cannot be covered).

Risk Mitigation measures include the following:

• Performing frequent hand hygiene
• Covering skin lesions (e.g., bandages, long sleeves, long pants, gloves). If a case’s lesions are not easily covered (e.g., face, hands) please advise the case to self-isolate until an assessment is completed by Public Health.
• Wear a medical mask for source control (if safe and tolerated) if there are lesions inside the mouth/oral cavity and/or respiratory symptoms such as a cough or sore throat present.
• Avoiding close or direct contact with individuals at higher risk of severe mpox illness where feasible (i.e., people who are immunocompromised and/or pregnant, children under 12 years of age), if possible.
• Avoiding interactions where prolonged close, direct skin-to-skin contact with others may occur (e.g., sexual contact, large crowds, participation in contact sports such as wrestling).
• Avoiding congregate settings (e.g., homeless shelter, long-term care facility), if possible.
• Avoiding use of shared recreational water facilities (e.g., pool, hot tub).

Keep mpox on the differential diagnosis in individuals with signs and symptoms that may be compatible with the disease. Maintain a high index of suspicion and low threshold to test for mpox in those with compatible signs and symptoms. Be sure to assess travel and immunization history.

Contacts should monitor for symptoms for 21 days after their last exposure. If they develop symptoms, contact Public Health and seek assessment from a health care provider.

Imvamune® Vaccine Information

Key Messages

• Imvamune® vaccine is approved in Canada for protection against mpox for both pre-exposure vaccination and post-exposure vaccination.
• Individuals with signs or symptoms of mpox infection should not receive the vaccine as the vaccine is not indicated in the treatment of mpox infection.
• Recent Ontario data has shown that persons who have received at least one dose of Imvamune® are less likely to report severe symptoms and to require hospitalization than persons who have not been vaccinated.
• Recent studies have shown vaccine effectiveness to be between 66-83% for patients with a 2 dose vaccine series.
• The vaccine is administered as a two-dose series spaced 28 days apart.
• The most common side effects of Imvamune® vaccine include reactions at the injection site like pain, erythema, induration and swelling. The most common systemic reactions observed after vaccination are fatigue, headache, myalgia, and nausea. Most of the reported adverse drug reactions observed in clinical trials were of mild to moderate intensity and resolved within the first seven days following vaccination.

Imvamune® vaccine for Pre-Exposure Vaccination

Refer to  the Ontario Ministry of Health's guidelines (external link), to determine if your patient  qualifies for pre-exposure vaccination at this time.

Travel is not an indication for the Imvamune® vaccine unless the individual meets Ontario’s current eligibility criteria. 

Imvamune® vaccine for Post-Exposure Vaccination

• The provision of Imvamune® vaccine for post-exposure vaccination requires an assessment of the risk of exposure by Halton Region Public Health.
• Post-exposure vaccination should be given within 4 days of exposure but can be given up to 14 days after last exposure.
• If patient reports contact to a confirmed or probable case of mpox, contact Halton Region Public Health to see if post-exposure vaccination is recommended.

How can my patients obtain Imvamune® vaccine for pre-exposure vaccination?

• Imvamune as either PreP or PEP can now be ordered from Halton Region Public Health by primary care providers to administer to their patients. Imvamune cannot be ordered through the Online Vaccine Ordering System. Imvamune orders must be placed by  faxing the High-Risk Vaccine Order Form (PDF file) to 905-465-3403. Orders will be distributed according to the current Vaccine Distribution Schedule. Learn more about ordering vaccines.
• The Halton Region Public Health Sexual Health Clinics is offering the Imvamune® vaccine for pre-exposure vaccination by appointment only to individuals who meet Ontario’s current eligibility criteria. Eligible individuals can book an appointment online. No OHIP card is required.

How can my patients obtain Imvamune® vaccine for post-exposure vaccination?

If a patient has had a high or intermediate risk exposure to mpox, the community health care provider should contact 311 to request Imvamune® vaccine for post-exposure vaccination to be administered in the health care provider’s office. The provision of Imvamune® vaccine as post-exposure vaccination for high-risk contacts requires an assessment of the risk of exposure by Halton Region Public Health.

Who can receive a second dose of the mpox vaccine?

Imvamune® is being offered as a two-dose primary series, with at least 28 days between first and second doses for individuals eligible for pre-exposure and post-exposure vaccination.

Please note, individuals who are eligible for pre-exposure vaccination and post-exposure vaccination who previously received an older generation replicating smallpox vaccine can be vaccinated with 2 doses of Imvamune®.

Additional resources

• Public Health Ontario Mpox Resources (external link)
• Public Health Agency of Canada: Mpox (external link)
• WHO fact sheet on mpox (external link)
• Public Health Ontario Focus on Mpox Vaccine (external PDF)
• Testing and Management of Mpox: Information for Primary Care Providers (external PDF)