Monkeypox: Public health management of cases and contacts in Canada

On November 28, 2022, the World Health Organization began using ‘mpox’ as the preferred term for monkeypox disease. We’ll be updating our content to reflect this change.

October 18, 2022

Note

Updates have been made to the last version (June 21, 2022), and include the following changes:

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Introduction

The Public Health Agency of Canada (PHAC), in collaboration with provincial/territorial (PT) public health authorities (PHAs) and other relevant federal government departments, has developed this document to provide guidance to PHAs working at the federal/provincial/territorial (FPT) level in the event cases of Monkeypox (MPX) virus are suspected or confirmed within their jurisdictions.

The strategy outlined in this guidance relies on rapid case and contact management with the goal of outbreak containment, including among priority populations or populations at higher risk of exposure to MPX and/or severe disease, and settings where transmission is occurring. To achieve this, the objectives for this guidance include rapidly stopping chains of transmission to prevent the establishment of MPX in Canada, and protecting public health and health care in Canada. This includes the protection of populations in Canada who are at risk of more severe disease from MPX infection (e.g., individuals who are immunocompromised, individuals who are pregnant, children under 12 years of age)Reference 1.

In addition, because MPX is not- widespread across Canada and the situation is quickly evolving, this document follows precautionary principles and approaches, in an effort to prevent the long-term establishment of MPX in Canada.

Guidance pertaining to diagnostic laboratory, specimen handling and transportation, clinical care, and infection prevention and control (IPAC) measures in other settings (e.g., Canadian points of entry, healthcare settings, long-term care facilities) are beyond the scope of this document.

This guidance is informed by the latest available scientific evidence, national and international epidemiological data and expert opinion; it is subject to change as new information becomes available and the situation in Canada evolves.

At the time of this update, the body of evidence surrounding MPX continues to be limited, with little recent scientific data available. PHAC continues to apply an evidence-informed approach to its case and contact management guidance for MPX; as new scientific information becomes available that triggers a shift in guidance, PHAC will adjust this document accordingly.

This guidance should be read in conjunction with relevant FPT and local legislation, regulations and policies, and adapted to local context as required. This document has been developed based on the Canadian situation and therefore may differ from guidance developed by other countries.

Background

Monkeypox virus in humans

MPX can be spread to humans three ways: animal to human, human to human, and likely through fomitesReference 2Reference 3Reference 4 For more information on the modes of transmission, clinical manifestations, diagnosis and treatment for MPX virus, refer to PHAC's Monkeypox: For health professionals webpage. Information on MPX for the general public is also available.

Current status

The MPX situation in Canada is evolving quickly. For up-to-date information, refer to PHAC's Monkeypox: Outbreak update webpage.

At the time of this update, most cases of MPX in Canada are in persons with multiple sexual partners, particularly men who report intimate sexual contact with other men. However, it is important to stress that the risk of exposure to MPX virus is not exclusive to any group or setting.

MPX illness is usually self-resolving. However, severe cases can occur and may be fatalReference 1. Based on genomic sequencing available to date, the outbreaks occurring in Canada are the result of transmission of Clade IIb of MPX, which historically has reported a case fatality rate of approximately 1-3%Reference 5Reference 6Reference 7 . For additional information on further detail regarding the MPX epidemiology in Canada, please refer to PHAC’s Monkeypox epidemiological update page.

Public health management of cases

Case definitions

National case definitions for MPX have been established and are being used for the context of this document.

Public health activities for case management

PHA's activities for case management may include:

Identifying all contacts during the case’s period of communicability, including, persons identified specifically as contacts by the case, and also groups of individuals potentially exposed during an event or while at a location, depending on the activities practiced while at those sites.

As individual situations vary and are unique, PHAs may need to modify isolation approaches used for cases. Modifications in isolation should be designed to maintain the objectives of this guidance (i.e., rapidly stopping chains of transmission, preventing the establishment of MPX in Canada, and protecting public health and health care in Canada).

Public health measures recommendations for suspected, probable and confirmed cases

When hospital-level care is not required, cases of MPX are recommended to isolate, from the start of symptoms until scabs have fallen off and there is evidence of epithelialization. This typically takes 2 to 4 weeks, but may take longer. The full spectrum of recommended PHM’s are outlined below.

General recommendations for isolation

Recommendations for interactions with others

Recommendations for interactions with animals (pets, livestock and wildlife)

Recommendations for environmental hygiene

The risk of fomite transmission of MPX remains difficult to characterize. In general, orthopoxviruses are known to be very stable in the environment and remain infectious for prolonged periods in scabs, especially in dark and cold environmentsReference 9Reference 10Reference 11. Materials contaminated with orthopoxviruses (e.g., clothes, paper, dust) can remain contagious for months to years if not disinfectedReference 9Reference 10Reference 11Reference 12Reference 13Reference 14.

Some limited evidence has found persistent MPX DNAReference 15Reference 16Reference 17Reference 18Reference 19, and in some cases, potentially infectious virusReference 17, on surfaces and fabrics directly touched by cases. However, many unknown factors remain, including the viral load needed for transmission to occur and the stability of infectious virus on surfaces and fabrics in various environmental conditions. Some small experimental studies have shown that despite environmental stability, poxviruses can be inactivated when exposed to standard chemical disinfectants and temperature greater than 50 degrees CelsiusReference 20Reference 21Reference 22Reference 23.

 In light of this, PHAs should advise cases and/or caregivers on proper environmental hygiene in the home, including recommendations for:

Detailed advice on environmental hygiene is available for cases and their caregiver’s on PHAC’s website.

Post-recovery safer sex practices

Public health measures for caregivers at the home

Ideally, only one individual in the home should provide direct care to the case, if and when needed (referred to as the "caregiver”). Health care providers entering the home to provide medical care should follow appropriate IPAC protocols.

The caregiver should not be someone who is at risk of more severe disease from MPX (e.g., individuals who are immunocompromised, individuals who are pregnant, children under 12 years of age)Reference 1 . Caregivers should self-monitor for signs or symptoms for 21 days since their last exposure to the case (see contact management section below for further details). If signs or symptoms develop, they should immediately notify the PHA and follow their instructions.

Caregivers should be provided instructions by the PHA on how to reduce their risk of MPX infection, which may include:

Public health management of contacts

Contact tracing

The purpose of contact tracing is to:

In Canada, local PHAs are responsible for initiating contact tracing. Once a case is identified, PHAs assess the need to begin contact tracing using the epidemiological and clinical information provided.

In determining the need to initiate contact tracing, the following factors should be taken into consideration:

Proactive communications to potential contacts

In addition to traditional contact tracing activities, PHAs should consider proactive, non-stigmatizing communication and outreach strategies to target groups that may be at higher risk of exposure based on current epidemiological data, in collaboration with local community-based stakeholders and organizations. This could also be instituted even before cases appear in the community, as an upstream approach.

PHAs may also find it beneficial to provide targeted messaging and advice on risk mitigation strategies for settings where there are social gatherings that have the potential for close physical contact, including for some individuals to engage in sexual contact (e.g., parties, clubs, raves, festivals). PHAs could also highlight that gatherings where substances (e.g., drugs and/or alcohol) are being used may also impact individuals’ assessment of risk and reduce adherence to safer sex practicesReference 24.

Risk assessment of contacts

All individuals who are contacts of a confirmed, probable or suspected case are recommended to be rapidly identified and assessed by PHAs, to determine their risk of exposure and the appropriate public health recommendations to follow.

To facilitate determining the public health recommendations, contacts are classified according to their risk of exposure in Table 1 below. Note that Table 1 provides guidance for classifying contacts as either high, intermediate or low risk, depending on their exposure, for the purposes of determining recommended actions. The information provided in Table 1 is not intended to replace more personalized public health advice provided to contacts, based on clinical judgement and comprehensive risk assessments conducted by PHAs.

Table 1: Classification of contacts by exposure risk level.
Exposure risk Description Possible Examples
High Prolonged or intimate contact, including any of the following:
  • Skin/mucosa to skin contact with a case (regardless of the case's lesion location)
  • Skin/mucosa contact with a case's biological fluids, secretions, skin lesions or scabs
  • Skin/mucosa contact with surfaces or objects contaminated by a case's secretions, biological fluids, skin lesions or scabs
  • Face-to-face interaction with a case, without the use of a medical mask by the case or contact
  • Sexual partner of a case
  • Household members living with a case
  • Roommate in a group home or student residence living with a case
  • Skin/mucosa contact with a case's unwashed bedding, towels, clothing, lesion dressings, utensils, razors, needles, sex toys, etc.
Intermediate
  • Any of the following:
    • Limited or intermittent, close proximity exposure to a case without wearing adequate PPE for the type of exposure risk (i.e., medical mask and gloves)
    • Shared living space where there are limited interactions with a case or their belongings
  • Sitting next to case on plane
  • Person sharing close proximity workspace with a case for long periods of time
Low or Uncertain
  • Any of the following:
    • Very limited exposures to a case
    • Consistently and appropriately using recommended PPE for the type of exposure risk (i.e., medical mask and gloves)
  • Brief social interactions with a case
  • Colleagues not sharing a confined or close-proximity office space with a case
Acronyms
  • PPE: Personal protective equipment
Note: This guidance is focused on community settings. For health care providers who have had an exposure to MPX, follow occupational health and safety advice or refer to PHAC guidance on infection prevention and control of monkeypox cases in healthcare settings.

Public health activities for contact management

For both high- and intermediate-risk MPX contacts, PHAs may conduct the following activities during the 21-day period since the contact's last exposure to the case:

Public health measures recommendations for contacts

Recommendations in Table 2 below apply for the 21-day period following the last exposure to a known suspected (unless MPX is ruled out), probable or known case.
Note: A risk assessment conducted by the PHA may further inform personalized PHMs recommendations, for example, PHAs may consider the following:

Table 2: Incremental public health measures recommendations for contacts based on exposure risk.
Exposure risk Recommendations
For all exposures
  • Can be permitted to continue routine daily activities, with some specific PHMs in place
  • Self-monitor for signs and symptoms of MPX infection
  • Practice proper hand hygiene and respiratory etiquette
  • Practice safer sex including: using condoms, dental dams, gloves and clothing to help reduce the risk of exposure to MPX for the person engaging in sexual activity with the contact
  • Notify the PHA and isolate immediately if signs or symptoms develop
  • Alert any health care providers that provide medical care of the potential exposure
  • Be aware that travelling during the 21-day post-exposure period could lead to unforeseen consequences if symptoms were to develop (e.g., the need to isolate abroad, seek medical attention and/or reschedule transportation, as well as the potential for additional financial costs)
For both intermediate- and high-risk exposure contacts
  • In addition to the above recommendations: 
    • Avoid high-risk settings (e.g., congregate living settings, such as correctional facilities or shelters) and populations at risk of more severe disease (e.g., individuals who are immunocompromised, individuals who are pregnant, children under 12 years of age, )Reference 1 , where possible
      • If this is unavoidable, consider wearing a well-fitting medical mask in these settings or around populations at high risk of more severe disease populations
      • For contacts who work in high-risk settings, refer to occupational health and safety advice or defer to the advice of their local PHA, based on a risk assessment
    • As a precaution to prevent possible spread to animals, it is recommended to avoid any close contact with animals (e.g. petting, kissing, cuddling, sharing sleeping areas, sharing food)
For high-risk exposure contacts
  • In addition to the above recommendations:
    • Wear a well-fitting medical mask whenever in the presence of others (including household members)
    • Refrain from sexual contact with others
    • Be especially vigilant when self-monitoring for symptoms if working with populations at risk of more severe disease

Additional Resources

Footnotes

Footnote a

In the absence of specific evidence about the effectiveness of barrier protection (e.g., condoms) to reduce the risk of MPX virus transmission, and with emerging evidence on the detection of MPX virus in seminal fluid, oropharyngeal and anorectal swabs among people with MPX infectionReference 25Reference 26Reference 27Reference 28, PHAC has taken a precautionary approach to recommendations for barrier protectionReference 26.

Return to footnote a referrer

References

Reference 1

E. M. Beer and V. B. Rao, "A Systematic Review of the Epidemiology of Human Monkeypox Outbreaks and Implications for Outbreak Strategy," PLOS Neglected Tropical Diseases, vol. 13, no. 10, p. e0007791, 2019.

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Reference 2

M. G. Reynolds, et al., "Clinical Manifestations of Human Monkeypox Influenced by Route of Infection," The Journal of Infectious Diseases, vol. 194, no. 6, pp. 773-780, 2006.

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Reference 3

R. H. Doshi, et al., "Epidemiologic and Ecologic Investigations of Monkeypox, Likouala Department, Republic of the Congo, 2017," Emerging Infectious Diseases, vol. 25, no. 2, pp. 273-281, 2019.

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Reference 4

A. Vaughan, et al., "Human-to-Human Transmission of Monkeyox Virus, United Kingdom, October 2018," Emerging Infectious Diseases, vol. 26, no. 4, pp. 782-785, 2018.

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Reference 5

E. M. Bunge, et al., "The Changing Epidemiology of Human Monkeypox - A Potential Threat? A Systematic Review," PLOS Neglected Tropical Diseases, vol. 16, no. 2, p. e0010141, 2022.

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Reference 6

H. Adler, et al., "Clinical Features and Management of Human Monkeypox: A Retrospective Observational Study in the UK," The Lancet Infectious Diseases, 2022.

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Reference 7

U.S. Centre for Disease Control and Prevention, "Update: Multistate Outbreak of Monkeypox - Illinois, Indiana, Kansas, Missouri, Ohio, and Wisconsin, 2003," 4 July 2003. [Online]. Available at Multistate Outbreak of Monkeypox - Illinois, Indiana, Kansas, Missouri, Ohio, and Wisconsin, 2003. [Accessed 2 June 2022].

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Reference 8

S. Seang, et al., "Evidence of Human-to-Dog Transmission of Monkeypox Virus," Lancet, vol. 400, no. 10353, pp. 658-659, 2022.

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Reference 9

S. Essbauer, H. Meyer, M. Porsch-Ozcurumez and M. Pfeffer, "Long-Lasting Stability of Vaccinia Virus (Orthopoxvirus) in Food and Environmental Samples," Zoonoses Public Health, vol. 54, no. 3-4, pp. 118-24, 2007.

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Reference 10

F. V. Rheinbaben, J. Gebel, M. Exner and A. Schmidt, "Environmental Resistance, Disinfection and Sterilization of Poxviruses," In: Mercer, A.A., Schmidt, A., Weber, O. (eds) Poxviruses. Birkhäuser Advances in Infectious Diseases. Birkhäuser Basel, pp. 397-405, 2007.

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Reference 11

H. Rouhandeh, R. Engler, M. Taher, A. Fouad and L. L. Sells, "Properties of Monkeypox Virus.," Arch Gesamte Virusforsch , vol. 20, no. 3, pp. 363-373, 1967.

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Reference 12

R. W. Sidwell, G. J. Dixon and E. McNeil, "Quantitative Studies on Fabrics as Disseminators of Viruses. I. Persistance of Vaccinia Virus on Cotton and Wool Fabrics," Appl Microbiol, vol. 14, no. 1, pp. 55-59, 1966.

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Reference 13

R. W. Sidwell, G. J. Dixon and E. McNeil, "Quantitative Studies on Fabrics as Disseminators of Viruses. 3. Persistence of Vaccinia Virus on Fabrics Impregnated with a Virucidal Agent," Appl Microbiol, vol. 15, no. 4, pp. 921-927, 1967.

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Reference 14

A. W. Downie, M. Meiklejohn, L. St Vincent, A. R. Rao, B. V. Sundara Babu and C. H. Kempe, "The Recoivery of Smallpox Virus from Patients and Their Environment in a Smallpox Hospital," Bull World Health Organ, vol. 33, no. 5, pp. 615-622, 1965.

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Reference 15

D. Nörz, et al., "Evidence of Sufrace Contaimination in Hospital Rooms Occupied by Patients Infected with Monkeypox, Germany, June 2022," Euro Surveill, vol. 27, no. 26, 2022.

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Reference 16

B. Atkinson, et al., "Infection-Competent Monkeypox Virus Contamination Identified in Domestic Settings Following an Imported Case of Monkeypox into the UK," Environ Microbiol, 2022.

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Reference 17

S. Gould, et al., "Air and Surface Sampling for Monkeypox Virus in UK Hospitals," NHS England Airborne HCID Network. medRxiv, 2022.

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Reference 18

J. Pfeiffer, et al., "High-Contact Object and Surface Contaiminiation in a Household of Persons with Monkeypox Virus Infection - Utah, June 2022," MMWR Morb Mortal Wkly, vol. 71, no. 34, pp. 1092-1094, 2022.

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Reference 19

C. N. Morgan, et al., "Environmental Persistence of Monkeypox Virus on Surfaces in Household of Person with Travel-Associated Infection, Dallas, Texas, USA, 2021," Emerg Infect Dis, vol. 28, no. 10, 2022.

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Reference 20

I. Tanabe and S. Hotta, "Effect of Disinfectants on Variola Virus in Cell Culture," Appl Environ Microbiol, vol. 32, no. 2, pp. 209-212, 1976.

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Reference 21

W. K. Joklik, "The Purification of Four Strains of Poxvirus," Virology, vol. 18, no. 1, pp. 9-18, 1962.

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Reference 22

G. Kampf, "Efficacy of Biocidal Agents and Disinfectants Against the Monkeypox Virus and Other Orthopoxviruses," Journal of Hospital Infection, vol. 127, pp. 101-110, 2022.

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Reference 23

G. Kampf, "Efficacy of Heat Against the Vaccinia Virus, Variola Virus and Monkeypox Virus," Journal of Hospital Infection, vol. 127, pp. 131-132, 2022.

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Reference 24

Public Health Agency of Canada, "Reducing the Health Impact of Sexually Transmitted and Blood-Borne Infections in Canada by 2030: A Pan-Canadian STBBI Framework for Action," 9 July 2018. [Online]. Available at Reducing the health impact of sexually transmitted and blood-borne infections in Canada. [Accessed August 2022].

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Reference 25

R. Sah, et al., "Monkeypox Viral Detection in Semen Specimens of Confirmed Cases: A Systematic Review and Meta-Analysis," Preprint in Research Square, 2022.

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Reference 26

D. Lapa, et al., "Monkeypox Virus Isolation from a Semen Sample Collected in the Early Phase of Infection in a Patient with Prolonged Seminal Viral Shedding," The Lancet Infectious Diseases, vol. 22, no. 9, pp. 1267-1269, 2022.

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Reference 27

N. Paran, et al., "Monkeypox DNA Correlates with Virus Infectivity in Clinical Samples," Preprint in bioRxiv, 2022.

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Reference 28

I. De Baetseilier, et al., "Retrospective Detection of Asymptomatic Monkeypox Virus Infectious Among Male Sexual Health Clinic Attendees in Belgium," Nat Med, 2022.

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