Mpox

Information and resources on mpox

Mpox, formerly known as monkeypox, is an orthopoxvirus that causes a disease with symptoms similar to, but less severe than, smallpox. Although most cases are mild and self-limiting, severe illness can occur.

Symptoms

Initial symptoms can include:

  • Fever
  • Chills
  • Headache
  • Myalgias
  • Lymphadenopathy
  • Fatigue

These symptoms are followed one to three days later by a progressively developing rash. The rash tends to begin on the face and spread to other parts of the body, including the hands, feet and genitals.

Transmission

Mpox is transmitted from animals to humans or person to person by close contact with infected bodily fluids, respiratory droplets, lesions or through items that have been contaminated with the infected person’s fluids or lesions (e.g., clothing, bedding). The potential for airborne transmission has also been suggested, given the respiratory system involvement during infection.

The incubation period is typically six to 13 days but can range from five to 21 days. Individuals are communicable from symptom onset until all scabs have fallen off and new skin is present.

IPAC precautions

Given the theoretical risk of airborne transmission, Public Health Ontario currently recommends airborne/droplet/contact precautions in addition to routine practices when providing care to patients with symptoms compatible with mpox. This includes wearing a fit-tested, seal-checked N95 respirator (or equivalent), gloves, gown and eye protection. The patient should wear a medical mask and be placed in a single room with negative airflow and a closed door.

Read about IPAC recommendations for mpox in health-care settings, including details on recommended room placement, laundry, environmental cleaning and waste disposal.

Testing

If you suspect that your patient has the mpox virus, you can call Public Health Ontario if you wish to consult them prior to sample collection and treatment. However, approval for testing and notification of specimen submission is not required.

  • Public Health Ontario’s customer service number: 416-235-6556 or 1-877-604-4567
  • After-hours on-call duty officer: 416-605-3113

As of June 2, 2022, clinical specimens from patients undergoing mpox testing have been temporarily reclassified as a Category B pathogen for land transport. Specimens requiring air transport still require Category A packaging and transportation. Staff performing specimen packaging should have training in the Transportation of Dangerous Goods (TDG).

Access Public Health Ontario’s mpox virus testing information website.

Currently, mpox virus testing is being done at Public Health Ontario’s laboratory testing site in Toronto, Ont. Results will be issued in up to two days once received.

In June 2022, the Ontario Association of Medical Laboratories released a memo stating that community laboratories in Ontario do not currently offer testing for mpox or collection services for diagnosing mpox (e.g., lesions, throat or nasopharyngeal swabs).

Skin specimens are preferred due to their much higher sensitivity (85 to 90 per cent) compared to nasopharyngeal/throat (60 to 70 per cent) and blood (40 to 50 per cent). Patients with two to three skin lesions that can be swabbed do not need blood or respiratory specimens collected for mpox. Specimens can be packaged and stored in the fridge for up to three days.

For patients with suspected mpox infection who do not have a rash (e.g., a patient who is a close contact with a confirmed case, or who has a febrile illness but no rash) or whose rash cannot be swabbed (e.g., macular and/or popular rash only), clinicians should submit a nasopharyngeal or throat swab along with a blood sample.

All specimens must be submitted with a Public Health Ontario general test requisition.

Clinicians are strongly encouraged to offer opportunistic STI testing (e.g., chlamydia, gonorrhea, syphilis and HIV testing) to patients when offering mpox testing.

Children with a rash consistent with an enterovirus illness (e.g., hand-foot-and-mouth disease) without epidemiological risk factors (e.g., contact with a confirmed case) do not require mpox testing.

Physicians who suspect that their patient has mpox virus should advise them to self-isolate pending a negative test result.

Patients with confirmed mpox infection should not be directed to community laboratories for any routine laboratory tests until all lesions have crusted over or the patient has been cleared for testing by public health. Patients with possible or suspected mpox who require urgent routine testing of serum or urine samples may be directed to community laboratories. Contact your local community laboratory to find out whether they can accommodate this specimen collection and to arrange an appointment.

Community laboratory couriers will support the transport of specimens collected from possible, suspected or confirmed mpox-infected patients if packaged appropriately by the submitting health-care practitioner. Once verifying the package is appropriate for transport, the courier will affix the TU 0886 certificate to the external package, if not already included by the submitter. Health-care providers are responsible for the packaging of their own samples; couriers are not able to oversee sample packaging.

Imvamune ® vaccine

The Ministry of Health has released mpox vaccine (Imvamune®) guidance for health-care providers. Imvamune® is a live attenuated third-generation replication-deficient smallpox vaccine manufactured by Bavarian Nordic and authorized by Health Canada in 2020 for adults aged 18 and older. Imvamune® can be offered as pre-exposure prophylaxis (PrEP) or post-exposure prophylaxis (PEP). This guidance from the Ministry of Health is consistent with NACI’s interim guidance.

Trans- or cis-gender individuals who self-identify as belonging to the gay, bisexual and other men who have sex with men community and meet one or more of the following criteria may be eligible for PrEP:

  • Have received a diagnosis of bacterial sexually transmitted infection (e.g., chlamydia, gonorrhea, syphilis) in the past two months
  • Have visited bathhouses, sex clubs or may be planning to, or work/volunteer in these settings
  • Have had anonymous sex or had more than two sexual partners in the last 21 days
  • Have engaged in sex work or may be planning to

Individuals who are immunocompromised, pregnant or breastfeeding may be at higher risk for severe disease from a mpox infection and should contact their local public health unit to be considered for PrEP if they are at risk for contracting mpox.

  • PEP may be offered to individuals who are a high-risk contact with a confirmed or probable case of mpox
  • Intermediate risk contacts may also be offered PEP following assessment by the local public health unit
  • A single dose of Imvamune® should be offered ideally within four days of exposure, but up to 14 days
  • Imvamune® should not be offered to people with a current mpox infection

The most common side effects include:

  • Pain
  • Erythema
  • Induration
  • Swelling
  • Fatigue
  • Headache
  • Myalgia
  • Nausea

Due to limited supply and ultra-cold storage requirements, public health units will not store Imvamune® on site. They will order the vaccine from the province once a need is identified.

TPoxx® treatment

The Ministry of Health has released mpox antiviral guidance for health-care providers that addresses Tecovirimat (TPoxx®), which is authorized by Health Canada under an extraordinary use indication for the treatment of human smallpox disease in adults and pediatric patients weighing at least 13 kg (29 lbs). Physicians can use their clinical judgment to prescribe TPoxx® off-label for the treatment of severe mpox infections.

Careful case-by-case assessment of risks vs. potential benefits for any individual mpox case should be done before administering TPoxx® treatment.

TPoxx® should be considered for:

  • Hospitalized patients with severe disease (e.g., hemorrhagic disease, sepsis, encephalitis, myocarditis or other conditions requiring hospitalization)
  • Patients who are severely immunocompromised
  • Pediatric populations, particularly children under 10 years of age
  • Pregnant or breastfeeding women
  • Patients with one or more complications (e.g., secondary bacterial skin infection, gastroenteritis with severe nausea/vomiting, diarrhea or dehydration, bronchopneumonia, concurrent disease or other comorbidities)
  • Patients with mpox virus infections with lesions that are leading to significant disability (e.g., proctitis, keratitis or other ocular involvement, pharyngitis/epiglottitis or other breathing/swallowing compromise)

Most common side-effects in adults include:

  • Headache and nausea followed by abdominal pain and vomiting

Less common side-effects include:

  • Gastrointestinal: dry mouth, chapped lips, dyspepsia, eructation and oral paresthesia
  • General pyrexia, pain, chills, malaise and thirst
  • Investigations: abnormal electroencephalogram, hematocrit decreased, hemoglobin decreased, heart rate increased and QTc prolongation
  • Musculoskeletal and connective tissue: arthralgia and osteoarthritis
  • Nervous system: migraine, disturbance in attention, dysgeusia and paresthesia
  • Psychiatric: depression, dysphoria, irritability and panic attack
  • Respiratory, thoracic and mediastinal disorders: oropharyngeal pain
  • Skin and subcutaneous tissue: palpable purpura, rash, pruritic rash, facial redness, facial swelling and pruritus

A limited supply of TPoxx® is available in Ontario for hospitalized patients who are severely ill or disabled due to mpox infection or at high risk for severe disease.

To request TPoxx®, email the Ministry of Health Emergency Operations Centre at EOCoperations.MOH@ontario.ca or call the Healthcare Provider Hotline at 1-866-212-2272.

Read the Q-and-A for mpox (MOH).

Reporting

On June 16, 2022, the chief medical officer of health released a memo informing that mpox has been designated a Disease of Public Health Significance as "Smallpox and other Orthopoxviruses including mpox" under the Health Protection Promotion Act. All suspected, probable and confirmed cases of mpox virus must now be reported directly to the local Medical Officer of Health in accordance with the reporting requirements in the Act, as per routine disease processes.

Physicians who suspect that their patient has mpox virus should advise them to self-isolate pending a negative test result.

Contact management

Close contacts should self-monitor for symptoms for 21 days after their last exposure. If symptoms develop, they should self-isolate, seek care and get tested.

Read the case definitions and disease-specific information (MOH).