MPOX Vaccine (Imvamune®)

What is MPOX?

• MPOX (formerly known as monkeypox) is a rare disease caused by the MPXV virus. It is part of the same family as smallpox, though typically less severe. Until recently, MPOX was found mostly in areas of Africa but since May 2022, it has been seen in other areas of the world, including Canada. MPOX causes flu-like symptoms such as fever and chills, and a rash develops within a few days. Although, there is no proven treatment, symptoms typically resolve on their own; however, severe cases resulting in death can occur.

What is Imvamune®?

• Imvamune vaccine is approved in Canada for protection against MPOX.

• It is a live vaccine, but it contains weakened virus and cannot make you sick.

• The vaccine is publicly funded and available for all eligible individuals. No OHIP required.

• Can be used before getting exposed to the virus (pre-exposure vaccination) or within 14 days after being exposed (post-exposure vaccination).

• Two doses of Imvamune at least 28 days apart are recommended. It takes two weeks to build protection.

• Imvamune cannot be used to treat MPOX and must be given before you have symptoms of MPOX.

 Eligible Groups:

1. For Pre-Exposure Vaccination:

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

• Had a confirmed sexually transmitted infection within the last year;

• Have or are planning to have 2 or more sexual partners or are in a relationship where at least one of the partners may have other sexual partners;

• Have attended venues for sexual contact (e.g. bathhouses, sex clubs) recently or may be planning to, or who work/volunteer in these settings;

• Have had anonymous sex (e.g. using hookup apps) recently or may be planning to; and/or

• Are a sexual contact of an individual who engages in sex work.

b) Individuals who self-identify as engaging in sex work or may be planning to, regardless of self-identified sex or gender.

c) Research laboratory employees working directly with replicating orthopoxviruses.

Household and/or sexual contacts of people who are eligible for Pre-Exposure Vaccination listed above in parts (a) and (b) AND who are either moderately to severely immunocompromised (have a weak immune system) or are pregnant may be at risk for severe illness from a MPOX infection. These individuals may be considered for Pre-Exposure Vaccination and should contact a healthcare provider or Brant County Health Unit for more information.

2. For Post-Exposure Vaccination:

• People who are a close contact of someone with MPOX, or were exposed in a setting where MPOX is spreading, should contact Brant County Health Unit to get assessed to see if the vaccine is recommended.

• When used as Post-Exposure Vaccination the vaccine should be given within 4 days, but can be given up to 14 days after the last exposure.

• People who got one dose as post-exposure vaccination can get a second dose at least 28 days later.

o People who are under the age of 18 should consult a healthcare provider before getting their second dose.

Get two doses of the MPOX vaccine for the best protection. The Bant County Health Unit offers MPOX vaccination in our immunization clinics. Eligible individuals can call 519-753-4937, ext. 451 to book an appointment. No Ontario Health Card is required.

Is the vaccine safe and effective?

• Yes, Like other vaccines, you may have some side effects, most are mild to moderate and go away within 7 days. Common side effects include: Redness, pain or swelling at the injections site, feeling tired, headache, muscle aches and nausea.

• If you received another vaccination in the past four weeks, let your health care provider know before getting Imvamune, but even if you have recently had another vaccine, do not delay getting Imvamune if you were exposed to mpox or are at high risk of exposure, as the benefits outweigh the risks.

• if you are pregnant, breastfeeding, immunocompromised, have atopic dermatitis or are less than 18 years of age, The National Advisory Committee on Immunization recommends that Imvamune may be offered if there is an exposure risk, after a risk / benefit discussion with your health care provider—.

Who should not receive the vaccine?

• If you are experiencing any symptoms of mpox, it is important to isolate right away and contact a health care provider. The vaccine is not used to treat mpox.

• Imvamune should not be given to individuals who have allergies to any of the ingredients in the vaccine including trometamol or benzonase. It has a bromobutyl rubber stopper.

• There are trace amounts of gentamicin, ciprofloxacin and egg products, but hypersensitive individuals can safely receive Imvamune and just need to stay 30 minutes for observation.

• 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 1st or 2nd generation smallpox vaccine, speak to your health care provider.

What else do I need to know?

• After getting the vaccine, it takes two weeks to build protection. During these two weeks, consider reducing your number of close contacts, including sex partners.

• After getting the Imvamune vaccine, wait at least two weeks before getting another non-live vaccine (e.g. COVID-19, flu or meningococcal) and four weeks before getting another live vaccine (e.g. MMR).

• If you have already had an older generation live smallpox vaccine or Imvamune vaccine, you can be re-vaccinated; check on this ministry guidance document.

When should I seek medical attention after immunization?

• If you or your child experiences any unusual side effects, seek medical attention & notify us.

• Go to Emergency at a hospital right away or call 911 if you or your child has any of the following after immunization:

o swelling of the face and neck

o problems breathing or shortness of breath

o hives and itchy, reddened skin

o chest pain or a pounding heartbeat

Sources: Imvamune® Product Monograph, Ministry of Health Vaccine Information Sheet and MPOX Vaccine Guidance,  

NACI Interim guidance on the use of Imvamune in context of MPOX outbreaks in Canada


  • Make sure to update your immunization record

This information is for general knowledge only and does not replace professional medical advice. Please note there is a cost for immunizations that are not included in Ontario’s Publicly Funded Immunization Schedule. For more information contact us at 519-753-4937 ext. 451 or