Mpox (formerly known as monkeypox)

Mpox is a disease caused by the monkeypox virus. It is a viral zoonotic disease, meaning that it can spread from animals to humans. It can also spread between people. Public Health Agencies around the world have reported cases of mpox since May 2022. Clade II of the virus has been detected in confirmed cases during the 2022 global outbreak. The virus typically causes a flu-like illness that leads to the development of a rash. In recent cases some individuals developed a rash (including oral, genital and/or perianal lesions) before or without fever and other symptoms. Some, but not all, may develop a more generalized rash.

Symptoms of mpox typically include:

• fever
• intense headache
• swollen lymph nodes
• low energy
• sweating/Chills
• muscle aches
• joint stiffness
• back pain
• skin rash or lesions

The rash usually begins within 1 to 3 days of the start of a fever. Lesions can be flat or slightly raised, filled with clear or yellowish fluid, and can then crust, dry up and fall off. The number of lesions on one person can range from a few to several thousand. The rash tends to be concentrated on the face, palms of the hands and soles of the feet. Symptoms can start within 5-21 days after exposure to mpox, but usually appear in 6-13 days. Symptoms last between 2 to 4 weeks and go away on their own without treatment.

Epidemiology on recent cases reported worldwide shows that some cases have been clustered in men who have sex with men. In addition, many of these cases have reported atypical symptoms, including unusual rash/lesions in the mouth and/or genitals before or without fever and other symptoms. Some, but not all, may develop a more generalized rash.

An individual can get mpox from an animal, through the bite or scratch of an infected animal, by handling wild game, or using products made from infected animals.

Mpox can spread from person-to-person by respiratory secretions, direct contact with skin lesions, and/or contact with materials contaminated with the virus (ex. bedding, clothing). The virus enters the body through broken skin, the respiratory tract or mucous membranes (ex. mouth, nose, eyes).

Transmission through respiratory secretions requires prolonged face to face contact with close proximity to an infected person. The virus can spread during intimate contact between people, including during sex, as well as activities like kissing, cuddling, or touching parts of the body with mpox sores. At this time, it is not known if mpox can spread through semen or vaginal fluids.

A person infected with mpox can be contagious 5 days before the rash appears, until the rash lesions have crusted and new skin has formed in 2-4 weeks. If someone is infected with mpox, they must self-isolate Instructions on when to stop self-isolating are provided by Public Health.

Most individuals with mpox will have mild symptoms and heal completely with no long-term effects. Children, pregnant women and people with underlying immune deficiencies are considered at higher risk for severe disease. Complications of mpox include:

• secondary bacterial infections
• bronchopneumonia
• sepsis
• encephalitis
• cornea infection

If you have symptoms of mpox, immediately self-isolate and call your health care provider. If contact with others is mandatory (e.g. seeking medical care), you should wear a high quality medical mask and cover up all lesions before leaving your home.

Make sure to call your health care provider's office and explain your symptoms prior to your appointment so that proper infection control measures can be put in place to prevent others from being infected with the virus.

Treatment for mpox is mainly supportive and most people will recover without treatment. If you are concerned, please contact your health care provider.

Imvamune® vaccine is approved in Canada for protection against mpox (external PDF) before getting exposed to the virus (pre-exposure vaccination) and after being exposed (post-exposure vaccination).

Imvamune® vaccine for Pre-Exposure Vaccination

Based on Ontario Ministry of Health's guidelines, persons who qualify for pre-exposure vaccination (external PDF) at this time are:

1. Two-Spirit, non-binary, transgender, cisgender, intersex, or gender-queer individuals who self-identify or have sexual partners who self-identify as belonging to 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 two 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., bath houses, sex clubs) recently or may be planning to, or who work/volunteer in these settings; or
   • Have had anonymous sex (e.g., using online dating/hookup apps) recently or may be planning to; and/or
   • Are a sexual contact of an individual who engages in sex work
2. Individuals who self-identify as engaging in sex work or may be planning to, regardless of self-identified sex or gender
3. Research laboratory employees working directly with replicating orthopoxviruses with an ongoing risk of exposure

Household and/or sexual contacts of those identified for pre-exposure vaccination eligibility in parts (a) and (b) above AND are moderately to severely immunocompromised (external PDF) or pregnant may be at higher risk for severe illness from a mpox infection and may be considered for pre-exposure vaccination and should contact their health care provider or public health unit for more information.

Moderately to severely immunocompromised household and/or sexual contacts must present with one of the following during their vaccine appointment:

• A completed referral form (PDF file) from their health care provider; or
• A current medication bottle or prescription receipt for a medication listed in Mpox Vaccine (Imvamune®) Guidance for Health Care Providers (external PDF), Table 2 List of Significantly Immunosuppressive Medications.
  • The prescription or medication bottle must include the:
    • client’s first and last name (must match a piece of identification); and
    • address and telephone number of the pharmacy that filled the prescription.
  • The prescription must have been prescribed or refilled within the past 6 months.
  • Active treatment with B-cell depleting therapies (monoclonal antibodies targeting CD19, CD20 and CD22) must have been completed within the last 12 months.

Halton Region Public Health Sexual Health Clinics will be offering Imvamune® vaccine for pre-exposure vaccination by appointment only.

Eligible individuals can call 311 to book an appointment; no OHIP card or ID is required.

For pre-exposure vaccination, it is currently recommended that people wait at least four weeks before and after the administration of a COVID-19 (mRNA) vaccine or a live vaccine and at least two weeks before and after receiving any other vaccine.

Consultation with your health care provider prior to immunization is encouraged if you are:

• under 18 years of age (note: Halton Region Public Health clinics are not currently offering vaccine for pre-exposure vaccination to anyone younger than 12 years of age)
• pregnant or breastfeeding
• severely immunocompromised
• have been diagnosed with atopic dermatitis
• had a previous allergic reaction to eggs or egg products, gentamicin, or ciprofloxacin
• have been diagnosed with myocarditis or pericarditis

Imvamune® vaccine for Post-Exposure Vaccination

• 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 you have been exposed to mpox, please contact Halton Region Public Health to find out if you are eligible for post-exposure vaccination.

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

Individuals who are household and/or sexual contacts of someone who meets pre-exposure vaccination eligibility AND are moderately to severely immunocompromised are also eligible to receive 2 doses of Imvamune® at least 28 days apart. For details of the definition of moderately to severely immunocompromised, please see Appendix A in the Mpox Vaccine (Imvamune®) Guidance for Health Care Providers (external PDF).

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 re-vaccinated. For individuals with a history of receiving 1 dose of a smallpox vaccine, only a single dose of Imvamune® is recommended.

Moderately to severely immunocompromised household and/or sexual contacts must present with one of the following during their vaccine appointment:

• A completed referral form (PDF) from their health care provider; or
• A current medication bottle or prescription receipt for a medication listed in Mpox Vaccine (Imvamune®) Guidance for Health Care Providers (external PDF), Table 2 List of Significantly Immunosuppressive Medications.
  • The prescription or medication bottle must include the:
    • client’s first and last name (must match a piece of identification); and
    • address and telephone number of the pharmacy that filled the prescription.
  • The prescription must have been prescribed or refilled within the past 6 months.
  • Active treatment with B-cell depleting therapies (monoclonal antibodies targeting CD19, CD20 and CD22) must have been completed within the last 12 months.

Eligible individuals can call 311 to book a first or second dose appointment for pre-exposure vaccination; no OHIP card or ID is required.

For post-exposure vaccination, speak with your health care provider regarding a second dose of the vaccine if the risk of exposure is expected to continue beyond 28 days following the first dose.

Anyone who does not meet the current eligibility criteria outlined by the Ontario Ministry of Health's(external PDF) is not eligible to receive the mpox vaccine.

People with signs and symptoms of mpox infection should NOT receive the Imvamune mpox vaccine as it is not intended for the treatment of mpox. Please follow-up with your health care provider for further assessment.

People who have a confirmed allergy to a previous dose of Imvamune® or any of the vaccine ingredients should consult with an allergy specialist before getting the vaccine. Ingredients of the Imvamune® vaccine are:

• Tromethamine (trometamol, Tris)
• Sodium chloride
• Hydrochloric acid
• Bromobutyl rubber stopper

Imvamune® may also contain trace amounts of:

• Gentamicin
• Ciprofloxacin
• Egg cell DNA and protein
  • People with a confirmed allergy to eggs or egg products may receive Imvamune and will be asked to stay at the clinic for a 30 minute observation post-vaccination.
• Benzonase

People who were vaccinated against smallpox are likely to have some protection against mpox infection. However, younger people are unlikely to have been vaccinated against smallpox because smallpox vaccination stopped in the 1970s after smallpox became the first human disease to be eradicated in 1980. Even though people who have been vaccinated against smallpox will have some protection against mpox, they also need to take precautions to protect themselves and others.

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 re-vaccinated. For individuals with a history of receiving 1 dose of a smallpox vaccine, only a single dose of Imvamune® is recommended.

If someone is exposed to a probable or confirmed case of mpox, they should self-monitor for symptoms for 21 days after their last exposure. If a fever or rash develops, they should immediately self-isolate, contact their local Public Health Unit and their health care provider.

No, mpox is not the same as chickenpox or smallpox. Mpox is caused by the monkeypox virus that belongs to the orthopoxvirus group. Smallpox is caused by the variola virus, which also belongs to the orthopoxvirus genus. Mpox presents as a milder version of smallpox, and causes lymph node swelling (lymphadenopathy), whereas smallpox does not. Chickenpox is caused by the varicella-zoster virus, which belongs to an entirely different virus group.

Anyone who has close physical contact with someone who has symptoms of mpox, or with an infected animal are at highest risk of infection.

Newborns, children and people with underlying immune deficiencies may be at risk of more serious symptoms and death from mpox. Health care workers are also at higher risk due to potential for longer virus exposure.

In general, mpox does not spread easily between people. The risk for most people in the community is considered to be very low.

There are number of measures that can be taken to prevent infection with mpox virus (external link):

• Practice physical distancing and wearing a mask
• Practice good hand hygiene after contact with infected animals or humans. For example, washing your hands with soap and water or using an alcohol-based hand sanitizer.
• Avoid contact with animals that could harbor the virus (including animals that are sick or that have been found dead in areas where mpox occurs).
• Avoid contact with any materials, such as bedding, that has been in contact with a sick animal or someone who is infected with the mpox virus.
• Use personal protective equipment (PPE) (external PDF) when caring for patients.

There are several types of animals that have been found to be susceptible to infection with mpox, including several species of rodents (e.g., rats, mice, hamsters, gerbils, squirrels, chipmunks, etc.), rabbits, hedgehogs, opossums, and non-human primates (e.g., monkeys). It is unknown which other species may be at risk of infection. Precautions should be taken to prevent exposure of any domestic or wild mammals to the virus.

Animals with mpox have been observed with clinical signs such as cough, fever, eye infections, lack of appetite, difficulty breathing, and rash. Veterinarians that suspect an animal has been infected with mpox should call the Ontario Ministry of Agriculture Food and Rural Affairs at 1-877-424-1300 to discuss the need for testing and/or management plans.

The risk of infection in different animal species is unclear, and because the mpox virus could be carried from one person to another on an animal's coat or feathers, it is best to find someone else to take care of your pet until you are out of isolation.

If you have or have recently been exposed to mpox and have been advised to self-isolate:

• Keep your pets in your home until 21 days after last exposure to a symptomatic person with mpox. If possible, ask someone else in your home who is not sick and who has not been exposed to care for your pets. For dogs that need to go outside periodically, keep them on leash and avoid contact with other people and animals.
• Avoid close or prolonged contact with pets, for example, avoid direct contact, including touching, snuggling, and kissing animals, especially if you have unhealed sores on your face, hands, or arms.
• Take precautions when providing care for pets, for example, wear a mask when in the same room as your pet, especially if you have sores in your mouth or are coughing/sneezing. Wash your hands with soap and water or use an alcohol-based hand rub immediately before and after touching pets, their food, or supplies.

If an animal develops unexplained signs of illness compatible with viral infection (e.g., fever, depression, not eating, respiratory signs, diarrhea, oral ulcers, skin lesions) within 21 days of having close contact with a person with mpox, a veterinarian should be consulted. It is preferred to first seek care from a veterinary telemedicine service, to assess if the animal’s condition can be managed at home.

If your pet must be examined directly by a veterinarian or requires other procedures that cannot be reasonably delayed until the end of the isolation period, your veterinarian should be advised that your pet may have been exposed to mpox. Your veterinarian should then contact the Ontario Ministry of Agriculture Food and Rural Affairs at 1-877-424-1300 to ensure that they have proper infection control procedures in place and appropriate personal protective equipment prior to attending your pet at home (ideally) or at a veterinary clinic (if necessary).

Anyone who is immunocompromised and/or pregnant, and children under 12 years of age, should avoid being caregivers to exposed or ill animals.

Any person who may have been exposed to mpox should not work with livestock or poultry until they are advised by their health care provider or public health unit that they don’t pose any risk for transmission of the virus. Animal owners are responsible for providing basic care for their animals including food, water, and shelter. Livestock and poultry producers should always have a plan in place for others to provide care for their animals in case of emergencies, including the need to self-isolate due to illness.

Any waste (i.e. bandages, gauze) that has come in contact with open sores or blood from an individual who is isolating from an exposure to mpox or has tested positive for mpox can be double bagged and placed in regular garbage. All other household waste can be disposed of in regular garbage.