Mpox Vaccine

Eligibility for protection before an exposure to mpox virus

Based on the Ontario Ministry of Health’s guidelines, individuals must meet the criteria below to be eligible for a mpox vaccine.

1) Two-spirited, non-binary, trans- or cis-gender individuals who self-identify or have sexual partners who self-identify as belonging to the gay, bisexual and other men who have sex with men (gbMSM) community AND at least one of the following:

• Have received a diagnosis of bacterial STI (i.e., chlamydia, gonorrhea, syphilis) in the past two months;
• Have had two or more sexual partners or may be planning to;
• Have attended venues for sexual contact (e.g., bath houses, sex clubs) or may be planning to, or who work or volunteer in these settings; or
• Have had anonymous sex (e.g., using hookup apps) or may be planning to; and/or
• Are a sexual contact of an individual who engages in sex work.

2)  Any individual who engages in sex work or may be planning to.

3) Household and/or sexual contacts of those identified for eligibility in parts (1) and (2) above

AND are moderately to severely immunocompromised or pregnant. These individuals may be at higher risk for severe illness from a Mpox infection. For more information on vaccine eligibility contact KFL&A Public Health or your healthcare provider. 

4) Individuals must be 18 or older. 

Receiving other vaccines before and after mpox vaccine

• To minimize potential risk of interactions, it is recommended to receive the mpox vaccine two weeks before or after receiving killed vaccines and/or four weeks before or after receiving live vaccines
• If you have received a vaccine within the above time frames, contact your health care provider to discuss further.

If you are immunocompromised or on immunosuppressive therapies (this includes HIV positive with a CD4 count of less than 100) please speak with your health care provider to see if the vaccine is right for you.

The vaccine is free and available to all eligible people. No ID or OHIP required. Wait to get vaccinated if you have symptoms of COVID-19 or required to self-isolate.

If you think you have mpox, it is important to isolate right away and contact a healthcare provider. Do not visit a mpox vaccine clinic. The vaccine is not used to treat mpox.

Imvamune® vaccine eligibility after being exposed to the mpox virus

At this time, people who have a known exposure or close contact with someone with mpox can get the vaccine as postexposure prophylaxis (PEP), even if they would not be eligible for pre-exposure prophylaxis (PrEP) vaccine .

When the vaccine is used as PEP, it should be given within four days, but can be given up to 14 days after the last exposure.

The vaccine is free and available to all eligible people. No ID or OHIP required. Wait to get vaccinated if you have symptoms of COVID-19 and/or required to self-isolate.

Based on the Ontario Ministry of Health guidelines, individuals who have been identified by their local public health unit as having a high or intermediate-risk exposure with someone who has the Mpox virus are eligible to receive Imvamune®. These individuals will be contacted directly by their local public health unit. If you think you have had close contact with someone who has mpox contact your healthcare provider or KFL&A Public Health to find out if you are eligible for vaccine.

If you think you have mpox, it is important to isolate right away and contact a healthcare provider. Do not visit a mpox vaccine clinic. The vaccine is not used to treat mpox.

Imvamune® vaccine side effects

Like other vaccines, this vaccine may cause some side effects. Most are mild to moderate, and go away on their own within seven days. Common side effects include:

• Redness, pain or swelling at the injection site
• Feeling tired
• Headache
• Muscle aches
• Nausea

Contact a health care provider or go to the nearest emergency department if you have any of these symptoms after getting the vaccine:

• Hives
• Swelling of the face or mouth
• Trouble breathing or shortness of breath
• Chest pain or a pounding heart

Imvamune® vaccine information sheet

This guidance provides basic information only. This document is not intended to provide or take the place of medical advice, diagnosis or treatment, or legal advice.

What is Imvamune®?

Imvamune® vaccine is approved in Canada for protection against smallpox, mpox, and other orthopoxvirus-related illnesses. The vaccine contains weakened virus and cannot make you sick.

Who should get the mpox vaccine?

Currently, in Ontario, one dose of Imvamune® can be received as:

1. Pre-Exposure Prophylaxis (PrEP), which means receiving the vaccine prior to any mpox exposure (for those who are likely to be exposed).

2. Post-Exposure Prophylaxis (PEP), which means receiving the vaccine after a potential exposure.

• The vaccine should ideally be given within four days but can be given up to 14 days after the last exposure.

• If you think you have been exposed to mpox, contact your local public health unit to see if you may be eligible to receive vaccine.

• Imvamune® is not a treatment for mpox.

Is the vaccine safe and effective?

• Yes, Imvamune® is safe to receive. The vaccine is effective at protecting against mpox when given before exposure to the virus.
• If you received another vaccination in the past four weeks, please let your health care provider know before getting Imvamune®.
• There is currently limited information on the use of the vaccine in certain populations. If you are less than 18 years of age, pregnant, breastfeeding, immunocompromised or have atopic dermatitis, you should speak to your health care provider.
• Your health care provider will review the risks and benefits of receiving the mpox vaccine.

Who should not receive the vaccine?

Imvamune® is not indicated for the treatment of mpox infection. If you are experiencing any symptoms of mpox, please let your health care provider know before receiving the vaccine. Imvamune® should also not be given to individuals who have allergies to any of the ingredients in the vaccine.

If you have a history of myocarditis (inflammation of the heart muscle) or pericarditis (inflammation of the outer lining of the heart) linked to a previous dose of a first or second generation smallpox vaccine, speak to your health care provider.

Please talk to your health care provider about the potential risks of getting this vaccine.

Does Imvamune® leave a scar like the smallpox vaccine?

No, Imvamune® will not leave a scar like previous smallpox vaccines as it is not given through scarification. Imvamune® is delivered through the subcutaneous route, which means that the needle is placed into the fatty tissue below the skin and above the muscle tissue.

Does Imvamune® have side effects?

Imvamune®, like other vaccines, may cause side effects, although not everyone will experience them. The most reported side effects are pain, redness or swelling at the injection site. Other common side effects may include fatigue, headache, muscle aches and pain, and nausea. These side effects are typically mild to moderate and on average did not last longer than seven days after receiving the vaccine.

No cases of myocarditis (inflammation of the heart muscle) or pericarditis (inflammation of the outer lining of the heart) have been identified in clinical trials of Imvamune®. If you develop any cardiac symptoms after receiving the vaccine, please contact your health care provider.

When should I call my health care provider?

Call your health care provider or go to the nearest emergency department if you experience any of the following symptoms after receiving the mpox vaccine:

• Hives
• Swelling of the face or mouth
• Trouble breathing
• Cardiac symptoms such as chest pain, shortness of breath or palpitations

Where can I get more information?

For more information on mpox, please see resources below, or talk to your health care provider.

• Ontario Ministry of Health – Mpox information page
• Public Health Ontario – Mpox information page
• Public Health Agency of Canada – Mpox: Outbreak update
• World Health Organization – Mpox information page
• World Health Organization – Mpox Q&A
• United States Centers for Disease Control – Mpox information page

Information about Imvamune® 

Vaccine overview

The Imvamune® vaccine:

• Is approved in Canada for protection against mpox.
• Is safe and effective.
• Can be used before getting exposed to the virus
• (pre-exposure prophylaxis - PrEP) or within 14 days after being exposed (post-exposure prophylaxis - PEP).
• Is injected into the fat layer on top of the muscle in the upper arm.
• Does not leave a scar like the older version of the smallpox vaccine.
• Teaches your immune system to recognize and fight the mpox virus.
• Takes two weeks after vaccination to give you protection.
• Contains modified virus and cannot make you sick.

The vaccine is free and available to eligible people. You do not need ID or OHIP.

Wait to get vaccinated if you have any COVID-19 or mpox symptoms, or if you are required to self-isolate. If you think you have mpox, it’s important to isolate right away and contact a health care provider.

Who should not receive the vaccine?

Speak to a healthcare provider before getting the vaccine if you:

• Have allergies to any components of the vaccine (ingredients include: Tris/tromethamine, bromobutyl benzonase, chicken protein, egg, gentamicin and ciprofloxacin
• Had any serious reaction to another type of smallpox or mpox vaccine.
• Are less than 18 years of age.
• Are pregnant or breastfeeding.
• Have a weak immune system (including organ transplant or HIV with low or unknown CD4 counts), as the vaccine may not be as effective in individuals with a weak immune system.

For Pre-Exposure Prophylaxis, it is currently recommended that people wait at least four weeks after receiving a live vaccine and at least 2 weeks after receiving an inactivated vaccine before receiving the mpox vaccine.