Updated: Public health management of cases and contacts associated with COVID-19  

Updated July 5, 2021

Note

This page is continually under review and updated as this situation evolves. Select updates have been made to the last version (April 22, 2021) in the following sections:

  • Introductory content
  • Contact management
  • Persons possibly exposed through travel
  • Contact tracing for airline passengers and flight crew

The updates in this version:

  • Reflect emerging evidence regarding vaccine effectiveness and increasing vaccine coverage in the Canadian population
  • Classify fully vaccinated contacts as low risk for the purposes of determining recommended public health authority (PHA) actions. This includes relaxation of quarantine recommendations for fully vaccinated contacts of cases (see Table 1), unless the risk assessment conducted by the PHA indicates otherwise
  • Adjust quarantine period language to allow for flexibility in situations where a combination of testing and quarantine may be used
  • Incorporate changes to reflect border measures policies

Please visit the provincial and territorial resources for COVID-19 page for updated guidance specific to your province or territory

On this page

The Public Health Agency of Canada (PHAC), in collaboration with Canadian public health experts, has developed this guidance for federal/provincial/territorial (FPT) public health authorities (PHAs) to support the management of individuals infected with or who may have been infected with the SARS-CoV-2 virus (i.e., "cases") and contacts of COVID-19 cases within their jurisdictions. It is recognized that PHAs may adjust case and contact management recommendations based on a risk assessment that would include the local epidemiology, vaccination coverage in the community, vaccination status of the contacts, etc.

The strategy outlined in this guidance focuses on case and contact management to mitigate the health impacts of COVID-19 on individuals in CanadaReferences 1. This guidance is set in the Canadian context and is based on the available scientific evidence and expert opinion. In interpreting and applying this guidance, it is important to recognize that the health, disability, economic, social, or other circumstances faced by some individuals and households may limit their ability to follow the recommended measures. This may necessitate adapted case management and contact responses by PHAs.

The response to the COVID-19 pandemic has been further strengthened by the availability of vaccines, but is further challenged by the emergence of variants of concern (VOC) within Canada and worldwide. Mutations in the SARS-CoV-2 virus that result in it being designated as a VOC are those which may cause increased transmissibility and/or potential changes in virulence and/or the possibility for immune escape. Monitoring for VOCs in general, particularly those with evidence of escape from natural/vaccine immunity, and those with increased transmissibility/severity is an important public health action to help inform case and contact management.

Evidence on the effectiveness of COVID-19 vaccines against asymptomatic infection in adults has begun to emerge from international post-marketing studies. Evidence suggests mRNA vaccines are moderately to highly effective against asymptomatic SARS-CoV-2 infection after a first dose (depending on time since vaccination as at least 2 weeks is needed for the immune response to develop) and highly effective against asymptomatic SARS-CoV-2 infection after a second dose. There are currently limited data specific to other COVID-19 vaccines, but studies are ongoing. Evidence on the effectiveness of COVID-19 vaccines authorized for use in Canada is summarized in the National Advisory Committee on Immunization’s (NACI) Recommendations on the use of COVID-19 vaccines statement and is updated as evidence evolves.

Provincial and territorial (PT) PHAs continue to adjust restrictive community-based measures (CBMs) based on the epidemiology of COVID-19 and vaccination coverage in their jurisdictions, taking into consideration other important indicators, such as sufficient public health capacity to test, to trace, to isolate and to quarantine a high proportion of cases and contacts, respectively, sufficient health care capacity to respond to surges and risk reduction measures are in place for high-risk populations (i.e., those at higher risk of developing more severe disease or outcomes) and settings.

This guidance is subject to change as new information on transmissibility and epidemiology becomes available. It should be read in conjunction with relevant PT and local legislation, regulations and policies. Coronavirus disease (COVID-19) outbreak updates are available.

Case management

Reporting and notification

The national case definition for COVID-19 provides surveillance case definitions as well as associated surveillance reporting requirements.

It is important for frontline health care providers to notify PHAs of cases of COVID-19 in accordance with jurisdictional reporting requirements. PHAs need to provide overall co-ordination with health care providers and provincial laboratories for the management and reporting of cases, and to establish communication links with all involved health care providers for the full duration of illness. PHAs should report confirmed cases of COVID-19, as well as probable cases where feasible, to PHAC within 24 hours of receipt of their own notification. National surveillance for Coronavirus disease (COVID-19) guidance is available. At the time of publication, a process for national reporting of VOCs has been approved, and provinces and territories are working closely with PHAC to implement and optimize this process to ensure national surveillance of VOCs.

In some instances, cases or contacts of cases are identified with epidemiological linkages that span two or more jurisdictions within and/or between provinces/territories. During case investigation, it may also be identified that the case acquired their infection, or was potentially exposed, in another jurisdiction. PHAs should use established inter-jurisdictional processes to enable timely case and contact management. Examples where this may be required include when a case travelled between jurisdictions during their communicable period; or when contacts reside in a different jurisdiction than a case.

Laboratory testing and screening

Laboratory testing strategies have evolved over time. Each PT has modified their approach (e.g., who is being tested and how) based on factors such as emerging evidence, new technology, laboratory capacity and local epidemiological circumstances. Information is available on the important roles that FPT governments play in COVID-19 testing.

At present, a validated reverse transcription polymerase chain reaction (RT-PCR) test on a clinically appropriate sample collected by a trained health care provider is the gold standard for the diagnosis of SARS-CoV-2 infection.

Appropriate laboratory testing for COVID-19 infection should be accessible by health care providers through community-based, hospital or reference laboratory services (e.g., a provincial public health laboratory (PHL) running a validated assay), or the National Microbiology Laboratory. In addition, PTs should have a process for screening and sequencing positive specimens for mutations common to VOCs. The establishment of screening assays looking for mutations specific to VOCs can provide results sooner than sequencing of virus samples and may be useful for informing timely public health action. However, not all VOCs will have common mutations so surveillance using partial or whole genome sequencing must be established by the PT. Although ideally, all positive specimens should be sequenced, when volumes preclude this, it is recommended that specimens from travelers, outbreaks and patients admitted to hospital should be prioritized and a subset of community-based specimens should also be selected for sequencing.

Guidance for health professionals related to laboratory testing is available. In addition, the Respiratory Virus Infections Working Group of the Canadian Public Health Laboratory Network has developed laboratory testing best practices for COVID-19 and has updated its protocol on microbiological investigation of emerging respiratory pathogens, including severe acute respiratory infectionsReferences 2References 3.

Rapid testing for COVID-19 using non-molecular assays has the potential to increase testing capacity; however, current data suggest that these methods are less sensitive than the current RT-PCR assaysReferences 4. The quick turn-around times and ease of use by a wide range of users allows rapid testing to be an important tool in a broader testing strategy (e.g., rapid testing of asymptomatic individuals in a cohort in which an outbreak is occurring or as part of a broader community-based testing strategy to help bring community transmission under control)References 5. Interim guidance is available for use of the nucleic acid- and antigen-based rapid detection tests.

Re-infection

There is evidence that, although uncommon, individuals can become re-infected with SARS-CoV-2References 6. The dynamics, duration, and nature of immunity produced during infection with SARS-CoV-2 are still unclear, but there is good evidence of immunity for at least several months in the majority of individuals previously infectedReferences 7. The evidence will be monitored to determine if there is a higher risk of re-infection associated with VOCs, which may impact future guidance on testing. Refer to guidance for laboratory testing for individuals suspected of being re-infected for more information.

Clinical management/treatment

Clinical management of the case, whether in the home or in an acute care setting, is based on the case's condition and at the discretion of the case's health care provider.

Health care providers involved in home care for a case should follow interim guidance developed for infection prevention and control in home care settings. Guidance for household members providing care for a case in the home, or occupants/staff in a co-living setting, are detailed in Appendix 1.

Case management in the community

Epidemiologic evidence suggests that the majority of people with COVID-19 do not require care in a hospitalReferences 8.

When care in a hospital is not required, cases should isolate themselves as soon as possible. If they are isolating in the home or co-living setting (e.g., student residence, group home, shelter, etc.), they should isolate away from other household members or occupants, as directed by their PHA.

Those who live alone, or in a home where the members of the household are in isolation or quarantine, should identify community and social supports (e.g., family, friends, social services) where possible to assist with essential needs, including care of pets when required, or consult with their local PHA for information about additional community resources.

Appendices 1 and 2 provide information regarding recommendations for isolation and assessment of a suitable isolation location respectively.

Seeking medical care

In the event of a medical emergency, the case or their caregiver should contact emergency medical services (911) or the local emergency helpline for medical assistance, including transportation to the hospital or clinic if necessary. If using an ambulance to travel to a hospital or clinic, inform the dispatcher that the person requiring medical care has COVID-19. Public transportation should not be used to seek medical care (if possible).

If using a private vehicle to seek medical care:

Isolating in the community

When advising individuals to isolate in the community-at home or in a co-living setting-it is important that the risk of transmission from the case to other members of the household or occupants in the co-living setting be minimized as much as possible.

Guidance for isolating at home or in other co-living settings, as well as recommendations when strict adherence to isolation requirements may not be possible, are available in Appendix 1.

Assessing suitability for isolation in the community

The PHA, in collaboration with the case and their health care provider, will determine the location where a case of COVID-19 isolates, as appropriate. It is important that cases who do not require hospital-level care convalesce in a suitable environment where effective isolation can be maintained and appropriate monitoring (e.g., for worsening of illness) can be provided.

Considerations for a suitable environment will depend on the individual and their living situation; and may vary depending on the sex, gender, or other socioeconomic or identity factors of the case. The vaccination status of other household members may also be taken into consideration. When feasible and as directed by the PHA, an alternate dwelling (e.g., hotel, self-containing unit) may be used for isolation of a case.

The PHA plays an important role in assessing the suitability of the case's isolation setting, and the considerations listed above are detailed in Appendix 2.

Psychosocial considerations

PHAs should encourage individuals, families and communities to create a supportive environment for people who are isolating to take care of their mental health, and minimize stress and hardship associated with isolation as the financial, social, and psychological impact can be substantial.

Obtaining and maintaining public trust are key to successful implementation of these measures. Clear messages about isolation, including the criteria, rationale, justifications, and duration, as well as ways in which persons will be supported during the isolation period, will help to generate public trust. Messaging should also be sensitive and tailored to the needs of populations confronting social, economic, cultural or other vulnerabilities. Additional information on the psychological impacts of COVID-19 is available.

For Indigenous Peoples, mandatory isolation away from home due to COVID-19 may trigger re-traumatization issues associated with experiences of forced removals in the past. There is also the potential for new trauma if their ability to be with their community, practice cultural and/or spiritual activities is limited. To avoid relocation of persons with COVID-19 to locations outside of their community, many Indigenous communities have re-purposed facilities or set up temporary structures to use as isolation sites so that community members may safely isolate in situations where their home setting is not suitable.

Public health monitoring of cases

Ideally, PHAs should provide or facilitate active daily monitoring of cases of COVID-19, including those infected with a VOC, as long as feasible based on available resources. If there are insufficient resources available to provide daily monitoring for all cases, PHAs should give consideration to prioritizing daily monitoring for cases infected with a VOC.

It is recognized that the frequency of monitoring of COVID-19 cases may vary by PHA and the local context, but generally, should include the following actions or advice:

PHAs should provide additional information about VOCs as required, such as when VOCs are circulating in the community or when a case has been diagnosed with a variant strain, including heightened vigilance for increased transmissibility if isolating at home or in a co-living setting with other household members or occupants.

Cases of COVID-19 should be monitored until they have met the criteria set by the PHA for discontinuing isolation.

Discontinuation of isolation for cases in the community

The PHA should direct the discontinuation of isolation of cases in the community (i.e., those not hospitalized or residents of long-term care facilities)Footnote b. Criteria may include:

In general, repeat laboratory testing (e.g., a negative test result) as the basis for discontinuing home isolation is not recommended. In most individuals with competent immune systems and those recovered from mild or moderate illness, prolonged or renewed RNA detection is not believed to reflect infectious virus, but rather non-infectious viral fragments, as viable virus has rarely been reported to persist for longer than 10 days in these populations. Additional information can be found in Guidance for repeated PCR testing in individuals previously positive for COVID-19.

There may be exceptions to these criteria for which PHA and/or clinical care providers may determine a longer isolation period is warranted (e.g., immunocompromised individuals, those hospitalized due to COVID-19). Discontinuation of isolation is not related to clinical management of cases. In some cases, clinical management may continue to be required after discontinuation of isolation.

Contact management

Contact management for community-based cases of COVID is the responsibility of local and provincial public health authorities, and is evolving as vaccine coverage in Canada increases and cases of COVID-19 are lowering in many jurisdictions.

It is important to identify and manage the contacts of cases of COVID-19 to reduce ongoing transmission of the virus in the communityReference 10. Several objectives may be achieved through contact management activities by PHAs, including:

Early identification of contacts, and direction regarding diagnostic testing for COVID-19 based on existing PT testing strategies, is a key component of rapid case identification and management to reduce transmission of the coronavirus. With the many unknowns associated with VOCs, testing of vaccinated individuals will be an important consideration of contact management.

In an outbreak context, contact tracing and management also serves the purpose of active case finding during an investigation. Where an outbreak is suspected, the PHA may adopt a situation-specific definition for those at high risk of exposure (i.e., "close contact") to help efficiently target their contact investigation and case finding efforts. For example, all individuals at an event associated with a high risk of transmission could be evaluated as being at high risk of exposure (e.g., all guests at a wedding, or participants of an indoor fitness class). This approach may be considered when the outbreak setting results in a high risk of exposure for most participants, or where risk assessments for individuals are not feasible.

Outbreaks may have a greater impact on certain groups due to their social, economic, health, or other risk factors, such as older age, having chronic medical conditions, living in a remote and isolated community, or living in poverty or crowded settings.

PHAs should give consideration to engaging in more rigorous outbreak investigation activities when an outbreak involves a VOC. This may include backward contact tracing or mass asymptomatic testing of individuals with known or suspected close contact exposure to a case with a VOC.

Contact tracing

The public health approach to COVID-19 case and contact management to date has largely focused on interrupting chains of transmission through contact tracing by identifying individuals at risk of exposure to SARS-CoV-2 from an identified case. The primary goal of contact tracing is to identify and to quarantine, or to facilitate self-monitoring of, individuals who are potentially exposed to a case to stop future chains of transmission.

Contacts should be identified and managed as per the recommendations in this document, where feasible based on public health resources. The level and intensity of public health actions may vary among jurisdictions according to the local epidemiology of COVID-19 at a given time and the identification of VOCs. Alternative contact management strategies that PHAs may consider when resources are constrained are detailed below.

The risk assessment conducted by the PHA can help identify each contact's exposure risk level, determine the appropriate intervention for the individual (e.g., quarantine, self-monitoring) and PHA actions for the recommended monitoring period. If the contact has been vaccinated, the PHA risk assessment may consider additional factors that could influence risk categorization and subsequent PHA actions. For example, these factors could include whether the contact has been partially or fully vaccinated, if the contact had been previously infected, if the contact is immune compromised, the time since last dose of vaccine or the potential risk of transmission to others, especially unvaccinated individuals who are at risk of more severe disease or outcomes from COVID-19. In addition, if there is significant spread of VOCs within the community or there is uncertainty about the risk assessment for a contact of a case infected with a VOC, PHAs may choose to adopt a more cautious approach when managing contacts as either high- or low-risk of exposure (see Table 1 below).

Given that transmission of SARS-CoV-2 can occur from cases who are symptomatic, pre-symptomatic, or asymptomatic, contact tracing should include:

For operational purposes, a minimum period of 48 hours prior to symptom onset (or positive test result) should be considered by jurisdictions for contact tracing. Under certain circumstances (e.g., outbreak management, VOCs, backward contact tracing), and given that in some instances the infectious period of a COVID-19 case may be longer than 48 hours, jurisdictions may extend contact tracing greater than 48 hours when public health capacity and/or the risk assessment warrants it.

Table 1 provides guidance for classifying contacts as either high or low risk, depending on their exposure, for the purposes of determining recommended actions. Fully vaccinated in this context means at least 14 days have passed since the completion of the recommended number of doses of a Health Canada approved COVID-19 vaccine. The information provided in Table 1 is not intended to replace more personalized public health advice provided to contacts, based on comprehensive risk assessments conducted by PHAs.

Table 1: Contact management recommendations by exposure risk level

Note: All potential exposures described below are considered to have occurred when the case was communicable in determining exposure risk level.

Risk Level Description Recommendations for the contact
High risk exposure (close contact)
  • HCW who is not fully vaccinated and who provided direct physical care to a case, or a laboratory worker handling COVID-19 specimens, without consistent and appropriate use of recommended PPE and infection prevention and control practicesFootnote c.
  • Anyone who is not fully vaccinated and lives with a case, has direct physical contact with a case, or is exposed to their infectious body fluids, including the case's caregiver, intimate partner, child receiving care from the case, etc.
  • Anyone who is not fully vaccinated and has shared an indoor space (e.g., same room) with a case for a prolonged period of timeFootnote d, including closed spaces and crowded places, (e.g., social gatherings, workplaces, etc.), without adhering to appropriate individual-level and setting-specific risk mitigation measuresFootnote e.
  • Anyone who is not fully vaccinated and has had a close-range conversation with a case or has been in settings where a case engaged in singing, shouting, or heavy breathing (e.g., exercise), without adhering to appropriate individual-level and setting-specific risk mitigation measuresFootnote e.
  1. Quarantine at home for 14 days from last exposure or for the recommended period determined by the local PHAFootnote f.
  2. Follow recommended personal preventive practices. If living with the case, avoid further exposure to the case and wear medical mask or a well-constructed and well-fitting, non-medical maskFootnote f when in a shared space (e.g., same room) with the case.
  3. Follow PHA directions related to testing requirementsFootnote g.
  4. Self-monitor for the appearance of symptoms consistent with COVID-19 for 14 days following their last exposure to the case.
  5. Take and record temperature daily and avoid the use of fever-reducing medications (e.g., acetaminophen, ibuprofen) as much as possible. These medications could mask an early symptom of COVID-19; if these medications must be taken, advise the PHAReference 12.
  6. If symptoms occur, isolate away from others within the home or co-living setting as quickly as possible; put on a medical maskFootnote a and contact the PHA for further direction, which will include:
    • where to go for care,
    • appropriate mode of transportation to use, and
    • IPC precautions to be followed.
  7. Avoid in-person interactions with others, especially those who are at risk for developing more severe disease or outcomes from COVID-19.
  8. Contacts who are at risk for developing more severe disease or outcomes should not provide care for the case and should stay elsewhere if feasible.
Low risk exposure
  • HCW (regardless of vaccination status) who provided direct physical care to a case, or a laboratory worker handling COVID-19 specimens, with consistent and appropriate use of recommended PPE and infection prevention and control practicesFootnote c.
  • Anyone (regardless of vaccination status) who has shared an indoor space (e.g., same room) with a case, including closed spaces and crowded places (e.g., social gatherings, workplaces, etc.), with adherence to appropriate individual-level and setting-specific risk mitigation measuresFootnote e.
  • Anyone (regardless of vaccination status) who has had a close-range conversation with a case or has been in settings where a case engaged in singing, shouting, or heavy breathing (e.g., exercise), with adherence to appropriate individual-level and setting-specific risk mitigation measuresFootnote e.
  • Fully vaccinated individuals in the above-mentioned high-risk exposure (close contact) situations would be considered to have a low risk exposure and be managed accordingly.
  1. Self-monitor for symptoms for 14 days following their last exposure.
  2. If symptoms occur, isolate away from others as quickly as possible, put on a medical maskFootnote a and contact the PHA for further direction, which will include:
    • where to go for care,
    • appropriate mode of transportation to use, and
    • IPC precautions to be followed.
  3. Where possible avoid interactions with individuals at higher risk for severe illness (this may not apply to HCWs who are using PPE and following IPC practices appropriately in their workplace)Footnote c.
  4. Follow PHA directions related to testing requirements.
  5. Follow recommended personal preventive practices.

Acronyms:

  • HCW: health care worker
  • PPE: personal protective equipment
  • IPC: infection prevention and control

Although transmission of SARS-CoV-2, including VOCs, may occur during brief exposures, transient interactions (e.g., walking by a case) have not been identified as high- or low-risk exposures in Table 1 because identifying such contacts is typically not feasible outside of digital contact tracing applications (see Alternative contact management strategies below).

Based on a risk assessment, PHAs may consider more robust approaches to contact management and quarantine specifications, particularly in the context of outbreak investigations involving VOCs. PHAs may also need to consider modifications to quarantine recommendations in some circumstances, such as the need for essential workers to maintain critical services. In these circumstances, jurisdictions may consider reducing quarantine with negative test results. At present, there is limited evidence to support this as a widespread approach, as there remains a residual risk of transmissionReference 13.

The duration of contact management for a contact who develops symptoms compatible with COVID-19 within 14 days of last exposure to a case should be based on the following considerations:

Alternative contact management strategies

To complement or accommodate limited local resources, PHAs may consider alternative approaches to traditional contact tracing, particularly when they are experiencing a local surge in casesReference 14. These may include the following:

During local peaks in COVID-19 activity and declared outbreaks, PHAs may also consider prioritizing contact tracing activities for specific settings where people gather (e.g., schools, events, workplaces, remote communities, etc.), and in particular, when epidemiologic features suggest a change in transmission dynamics (e.g., when a VOC is suspected or confirmed). PHAs may also consider prioritizing follow-up of contacts (e.g., those with vulnerabilities, those who work in high-risk settings, or those who provide care to someone with vulnerabilities, etc.)Reference 15.

PHAs may also consider alternative approaches where cases, employers, or event coordinators notify contacts (i.e., simple referral); or notify contacts and provide additional information related to infection prevention and control, quarantine, and symptom monitoring (i.e., enhanced referral)Reference 16.

Backward contact tracing

PHAs may also consider 'backward' contact tracing, which focuses on trying to determine where and when the case likely acquired their infection. Backward contact tracing is routinely done as part of case or outbreak investigations for communicable diseases of public health significance, when PHAs collect information on a case's potential acquisition history. In this guidance, backward contact tracing is proposed as a less intensive activity, and therefore potentially less resource intensive, compared to outbreak investigation.

While COVID-19 has been observed to spread steadily in the community, with one case infecting one or two other individuals on average, clusters have been identified where some individuals disproportionately infect a larger number of individuals. This represents a statistical concept called over-dispersion, where there is high individual-level variation in the distribution of the number of secondary transmissions. Clusters associated with these cases have been referred to as super-spreading events (SSEs).

Mutations in the genetic code of SARS-CoV-2 can also cause the virus to act in ways that have significant impacts on case and contact management (e.g., increases in disease spread or severity; its ability to become undetectable by tests; or the effectiveness of vaccines or treatments).

In these circumstances, 'backward' contact tracing may help to:

If the source case is identified through backward contact tracing, contact tracing to identify individuals who may have been exposed to a case should be employed as detailed above, and contacts managed based on their risk of exposure as described in Table 1. Depending on a given situation, testing requirements and public health interventions may need to be scaled based on local epidemiology.

Backward contact tracing is considered to be most useful when localized outbreaks may be occurring in areas experiencing relatively low levels of transmission. It may also be considered for investigating outbreaks with an epidemiologic feature suggestive of change in transmission dynamics (e.g., where a VOC is implicated).

It is considerably more challenging when there is widespread community transmission, due to the volume of cases and uncertainty created by having multiple potential sources of transmission for any given case. Backward contact tracing may also be less useful during periods of restrictive public health measures, due to fewer events or localized settings where outbreaks or SSEs might occurReference 17. Employing backward contact tracing approaches may have significant resource implications, depending on the specific contact tracing strategies used, approaches to testing, and local epidemiology.

There is currently limited evidence regarding the effectiveness of backward tracing for COVID-19, so it is not possible to be definitive about when it would be most useful or how it would be best implemented. A limited number of countries have utilized this strategy, and beneficial impact was correlated with low incidence and limited community transmissionReference 18Reference 19.

Provinces/territories (PTs) should consider the utility of backward contact tracing based on their individual circumstances and available resources and, if implemented, consider evaluating the effectiveness in order to contribute to the evidence base for this practice.

Persons possibly exposed during travel

In response to the COVID-19 pandemic, all travellers entering Canada are subject to the rules set out by the emergency orders under the Quarantine Act.

Current information regarding travel, testing, quarantine and borders requirements can be found at COVID-19: Travel, testing and borders.

History of travel should be considered by PHAs during a risk assessment during contact tracing. Potential travel-related exposures on specific conveyances (e.g., flights, trains, cruise ships) may be available.

Contact tracing for airplane passengers and flight crew

Potential exposure to SARS-CoV-2 among passengers and crew during air travel is a topic of concern; however, risk mitigation measures such as vaccination status, mandatory use of masks, physical distancing, reduced occupancy, ventilation, environmental cleaning, and hand hygiene, applied in a layered approach, can significantly reduce the likelihood of transmissionReference 20.

Decisions related to contact tracing individual airplane passengers and flight crew who may have been exposed to a confirmed case of COVID-19 on any flight should be made based on available resources and a risk assessment. Risk assessments should be conducted by the PHA to which the case is notified, considering the following:

If the province/territory determines that notification to potential contacts is required, the PHA can follow local protocols for publicly communicating when a case has had a history of travel during their period of communicability. The information required is the flight number, flight date, departure/arrival locations, and affected rows of the flight. Additionally, flight exposure notifications received by PHAC's Inter-jurisdictional Notices (IJN) team can be posted on the COVID-19: Passenger transport where you may have been exposed webpage.

Appendix 1: Recommendations for isolation of COVID-19 cases in the community

When care in a hospital is not required, cases of COVID-19 should isolate themselves as soon as possible. If they are isolating in the home or co-living setting (e.g., shelter, group home, or student residence), they should isolate away from other household members or occupants, as directed by their PHA. It is recommended the case isolate in a separate room for sleeping with access to a separate washroom from other household members or occupants, if possible. When feasible and as directed by the PHA, cases could isolate in an alternate dwelling such a hotel or self-containing unit. They should isolate for a minimum of 10 days from the onset of symptoms for a symptomatic case, or the collection date of a positive specimen for an asymptomatic case.

During isolation, the case should not leave the isolation setting, whether it is their home, co-living setting, or an alternate setting identified by their PHA or health care provider. They should:

Isolating in the community

When advising individuals to isolate at home or in a co-living setting, it is important that the risk of transmission from the case to other members of the household or occupants in the co-living setting be minimized as much as possible. Advice is available for individuals who are required to isolate at home due to COVID-19.

As much as possible, the following strategies should be used during isolation in the community:

Recommendations when strict isolation is not possible

Cases of COVID-19 who have been directed to isolate may not be able to strictly follow instructions for isolation in the home or co-living setting. This may be due to the isolation setting itself, for instance, there are not enough rooms in the home for the case to have a separate room or a dedicated washroom, or occupants in a shelter who must share space. It may also be difficult to isolate due to other factors; for example, if the case is a child, has child-/elder- care responsibilities, or lives in a multigenerational household.

When it is not possible to relocate the case, or members of the household or co-living setting, the following approaches may be considered:

Appendix 2: Assessment of a suitable isolation location for a case of COVID-19

The location where a COVID-19 case will be isolated should be determined by the public health authority (PHA), in collaboration with the case and their health care provider, as applicable. It is important that cases who do not require hospital-level care convalesce in a suitable environment where effective isolation and appropriate monitoring (e.g., for worsening of illness) can be provided.

Considerations for a suitable environment will depend on the individual and their living situations, and may vary depending on the sex, gender, or other socioeconomic or identity factors of cases.

Factors to consider when determining the suitability of an isolation location:

Can the case's clinical condition be managed as an outpatient?

For isolation in the community, including the home or a co-living setting (e.g., shelter, group home, student residence, etc.), it must be possible to manage the case as an outpatient, taking into consideration their baseline health status and the presence of risk factors for more severe disease or outcomes. If hospitalization is required (e.g., worsening condition, health emergency, direction of health care provider), home isolation will no longer be feasible.

Is the case able to manage their own care?

Symptomatic and asymptomatic cases should be able to monitor themselves for new or worsening symptoms; take appropriate action as advised by the PHA or their health care provider, including self-care; properly wear a medical maskFootnote a; maintain appropriate personal preventive practices (e.g., maintain proper hygiene practices, clean and disinfect high-touch surfaces, etc.), and isolate away from others.

A case's ability to manage their own care may be impacted by various factors, including:

Does the case require care? Is someone available to provide the care?

Some circumstances may require a household member to provide care to the case; for example, when the case is a child, an elderly relative who requires support, or a case who is very ill. When this occurs, the following should be considered:

What are the characteristics of the home or co-living configuration?

Cases may be in various household configurations that may hinder their ability to isolate themselves. For instance, the case may be a single-parent who must provide care to a child, or they may live in a multi-generational home with shared child- and elder-care responsibilities. If the case provides care to a child where childcare is shared between parents in two separate homes, consideration should be given to the most appropriate location for the child while the case is isolating.

If the case is isolating in their home or co-living setting, they should isolate away from others as soon as they are notified they have or may have COVID-19. Special consideration is also needed to support cases living in homes where it is difficult to separate from others (e.g., a one-bedroom apartment), or are living in co-living settings, such as student residence, shelters, and overcrowded housing,. The preferred option is to provide the case in these settings with a single room and a private washroom, which may require relocating the case, their roommates, or other household members to another location, (e.g., hotel, self-containing unit), if possible and as directed by the PHA. Relocation will be dependent on a variety of factors, including guidance from the jurisdiction’s PHA, financial support, and availability of alternate spaces.

If it is not possible to provide the case with a single room and a private washroom in the co-living setting, or to relocate the case, efforts should be made to cohort confirmed cases together. For example, if two cases reside in a co-living setting and single rooms are not available, they could share a double room. Specific guidance has been developed on the considerations for people experiencing homelessness and for post-secondary institutions.

Are there others with greater risk of more severe disease or outcomes in the home or co-living setting?

Household members, or other occupants in co-living settings, who are at risk for more severe disease or outcomes from COVID-19 should not provide care to the case and alternative arrangements may be necessary. This could include temporarily relocating these individuals or the case outside of the home to a location determined by public health, such as a designated hotel.

Is the home or co-living setting suitable for isolation?

The PHA should determine if the home or co-living setting is suitable for isolation of the case. Cases may live in conditions where they lack available space to provide a dedicated room and private washroom for the case, such as an overcrowded house, student residence where the case has a roommate, or a homeless shelter. Housing conditions should also be assessed, including access to potable, running water, and the state of repair of the home. Safety of the setting should also be assessed in terms of the potential occurrence of gender-based or family violence or other abuse.

Can the case access adequate supplies and necessities?

Consider whether or not the case has access to supplies and necessities for the duration of isolation, such as food, running water, drinking water, supplies for infection control (e.g., masks), and cleaning supplies. A list of supplies to have on-hand while isolating is available. Those residing in remote and isolated communities may wish to consider stockpiling the needed supplies, as well as food and medications usually taken, if it is likely that the supply chain may be interrupted or unreliable.

A case who does not have access to adequate food or necessary supplies could contact local leadership, public health or organizations that provide direct support. Guidance is available for hand washing in the absence of running or clean water.

If the home or co-living setting is inadequate for home isolation based on the assessment, PHAs should collaborate with the case and their health care provider, to determine a more suitable location. This may involve relocating the case to a more suitable community setting, hospitalizing the case, or accessing additional community supports and resources where available.

Appendix 3: Recommended infection prevention and control precautions when caring for a case in the home or co-living setting

Anyone who provides care to a case of COVID-19 should wear a medical maskFootnote a, as well as eye protection whenever providing care. Caregivers should also frequently wash their hands, especially when in direct contact with the ill person or their environment, including soiled materials and surfaces.

Advice is available to support those caring for someone with COVID-19 at home:

Additional information may be provided to caregivers in the home related to how to appropriately put on (don) and take off (doff) eye protection and gloves.

Eye protection

Eye protection is recommended to protect the mucous membranes of the caregiver's eyes while providing care to a case of COVID-19, or during any activities likely to generate splashes or sprays of bodily fluids, including respiratory secretions.

Gloves

Caregivers do not have to wear disposable single-use gloves when caring for someone in the home setting. Frequent hand washing is preferred.

However, caregivers may still choose to wear disposable single use gloves, when in direct contact with the ill person, cleaning contaminated surfaces, and handling items soiled with bodily fluids, including dishes, cutlery, clothing, laundry, and waste for disposal.

Gloves are not a substitute for hand hygiene; caregivers must perform hand hygiene before and after putting on and taking off gloves.

Acknowledgments

The Public Health Measures (PHM) technical guidance is developed and approved in collaboration with federal, provincial and territorial partners, via the Technical Advisory Committee (TAC) and/or the Special Advisory Committee (SAC). In its guidance development process, PHM also works closely with: multilateral partners; other government departments; First Nations, Inuit and Métis stakeholders (through the Public Health Working Group on Remote and Isolated Communities); Sex and Gender-based Analysis (SGBA) experts at Public Health Agency of Canada; and other external stakeholders with a vested interest or a stake in the guidance.

This current iteration was prepared by: Lynn Cochrane, Lisa Paddle, Corey Green, Abraham Abood and Harunya Sivanesan

Previous iterations prepared by: Nicole Winters, Jill Sciberras, Jill Williams, Lynn Cochrane, Corey Green, Sharon E. Smith, Angela Sinilaite, Alexandra Nunn, Fanie Lalonde and Lisa Paddle

and supported by: Canadian Pandemic Influenza Preparedness (CPIP) Task Group Members, an external expert group: Bonnie Henry, Susy Hota, Brian Schwartz, Carolina Alfieri, Ian Gemmill, Kim Daly (ISC), Pamela Wolfe-Roberge, Todd Hatchette, Erin Henry, Nadine Sicard, Michelle Murti and Eleni Galanis

Footnotes

Footnote a

In situations where a medical mask is recommended but not available, the individual should properly wear a well-constructed and well-fitting non-medical mask.

Return to footnote a referrer

Footnote b

COVID-19 guidance for acute care settings: https://www.canada.ca/en/public-health/services/diseases/2019-novel-coronavirus-infection/health-professionals/infection-prevention-control-covid-19-second-interim-guidance.html COVID-19 guidance for long-term care settings: https://www.canada.ca/en/public-health/services/diseases/2019-novel-coronavirus-infection/prevent-control-covid-19-long-term-care-homes.html#a22

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Footnote c

This guidance is focused on community settings, and does not replace point-of-care risk assessments by health care providers in health care settings, or a risk assessment conducted by PHAs to determine the exposure risk for a health care worker (HCW).

Guidance related to the appropriate use of personal protective equipment (PPE) and infection prevention and control for HCWs and laboratory workers is available. See the following guidance documents:

Return to footnote c referrer

Footnote d

There is insufficient evidence available to define risk in terms of the length of exposure time required for transmission. For public health contact identification and management purposes only, a period of 15 cumulative minutes over 24 hours has been selected to distinguish between brief and prolonged exposure. This same period has been used in other countriesReference 14Reference 25Reference 26. This parameter should not replace the conclusions derived from a risk assessment, conducted by the public health authority, that addresses a variety of factors (i.e. infectiousness of the case at time of exposure, exposure is to a VOC, likely route of transmission, risk factors, etc.) that will more precisely inform risk.

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Footnote e

The high and low risk exposure categories in Table 1 offer a simple guide for assessing a contact's risk of exposure to COVID-19 during contact tracing. In reality, there is a spectrum of risk, where adherence to public health risk mitigation measures helps to decrease the chance of infection. A risk assessment conducted by the PHA may further inform personalized recommendations.

Individual-level risk mitigation measures for consideration in the risk assessment include adherence to personal preventive practices (e.g., mask wearing, hand hygiene, physical distancing, etc.) by both the case and the contact. It should also include whether or not the contact avoids settings or activities where they may be exposed, including closed spaces and crowded places, as well as settings where these factors overlap and/or involve activities such as close-range conversations, singing, shouting, or heavy breathing. Setting-specific considerations include those places where a contact was potentially exposed, including whether the exposure was indoors (higher risk) or outdoors (lower risk), ventilation quality, the size and number of people in the setting, and risk mitigation measures in place in the setting (e.g., requirements for wearing masks, physical distancing, cleaning high-touch surfaces, etc.)Reference 27.

Although outdoor settings are not generally considered high risk, the potential for transmission still exists under certain circumstances, such as close conversations or rigorous exercise when participants are in close proximity and are not wearing masks; therefore, public health authorities should consider these risks when classifying contacts based on riskReference 27.

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Footnote f

The quarantine period typically aligns with the period of communicability. However, PTs may opt to implement a reduced quarantine period in combination with testing protocols, depending on the risk assessment and local circumstances.

In general, quarantine means that a contact stays in their home and does not go out, and avoids in-person interactions with others, including their household members.

A contact who does not live with a case should quarantine away from other household members or occupants, as directed by their PHA. It is recommended the contact quarantine in a separate room for sleeping with access to a separate washroom from other household members or occupants, if possible. When feasible and as directed by the PHA, a contact who does not live with the case could quarantine in an alternate dwelling such a hotel or self-containing unit.

A contact who does not live with a case should wear a non-medical mask when in shared spaces (e.g., kitchen, washroom, hallway) in the home or co-living setting, regardless if others are present.

For contacts in quarantine who are living with a case, it is recommended they wear a medical mask or a well-fitted, well-constructed and properly worn non-medical mask when in a shared space (e.g., the same room) as the case. Jurisdictions may adjust mask recommendations depending on local circumstances (e.g., if VOCs are circulating in the community; if the case and household contacts are living in a overcrowded or poorly ventilated setting).

For contacts in quarantine who are living with a case, the PHA will determine when their quarantine period begins by assessing the characteristics of the setting. If it is determined that there is adequate separation between the case and their household members, the PHA may advise that household members' quarantine period begins the day the case goes into isolation. If there is inadequate separation (e.g., shared sleeping quarters, shared washroom, etc.), the PHA may require household members to quarantine for the duration of the case's isolation period, plus up to an additional 14 days afterwards.

If additional members of a household with a case become ill, the PHA should assess whether other asymptomatic household members need to extend their period of quarantine based on their last exposure to the new case.

Return to footnote f referrer

Footnote g

Jurisdictional specific testing policies/capacity could have implications on individual quarantine recommendations within that jurisdiction

Return to footnote g referrer

Footnote h

The 2-metre parameter should not replace the conclusions derived from a risk assessment conducted by the PHA that addresses a variety of factors (e.g., infectiousness to the case at time of exposure, exposure is to a VOC, the likely route of transmission, increased risk of more severe disease or outcomes) that will more precisely inform risk.

Return to footnote h referrer

Footnote i

For operational purposes, an appropriate physical distance is at least 2 metres. In general, if in-person interactions must take place, individuals should be encouraged to interact from the greatest distance possible, and with other personal preventive practices in place for a layered approach.

Return to footnote i referrer

References

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Respiratory Virus Infections Working Group, "The Canadian Public Health Laboratory Network protocol for microbiological investigations of emerging respiratory pathogens, including severe acute respiratory infections," Can Commun Dis Rep, vol. 46, no. 6, pp. 205-209, 2020.

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Deeks, J.,Dinnes, J., Takwoingi Y., et.al,, "Diagnosis of SARS‐CoV‐2 infection and COVID‐19: accuracy of signs and symptoms; molecular, antigen, and antibody tests; and routine laboratory markers," Cochrane Database of Systematic Reviews, no. 4, April 2020.

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Government of Canada, "Coronavirus disease 2019 (COVID-19): Epidemiology update," 22 June 2020. [Online]. Available: https://health-infobase.canada.ca/covid-19/epidemiological-summary-covid-19-cases.html. [Accessed 11 March 2021].

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Mathai, V., Das, A., Bailey, J. A., & Breuer, K., "Airflows inside passenger cars and implications for airborne disease transmission," Science Advances, vol. 7, no. 1, 2021.

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Juneau, C., Briand, A., Pueyo, T., Collazzo, P., Potvin, L., "Effective Contact Tracing for COVID-19: A Systematic Review," PrePrint: medRXiv, 2020.

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Reference 12

Wahba, H., "The antipyretic effect of ibuprofen and acetaminophen in children," Pharmacotherapy: The Journal of Human Pharmacology and Drug Therapy, vol. 24, no. 2, pp. 280-284, February 2004.

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Reference 13

A. Otten and L. Waddel, "Evidence breif of COVID-19 quarantine length and reduction strategies and effectivness, Update 1".

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Reference 14

European Centre for Disease Prevention and Control, "Contact tracing for COVID-19: current evidence, options for scale-up and an assessment of resources needed," 5 May 2020. [Online]. Available: https://www.ecdc.europa.eu/en/publications-data/contact-tracing-covid-19-evidence-scale-up-assessment-resources. [Accessed 11 March 2021].

Return to footnote 14 referrer

Reference 15

European Centre for Disease Prevention and Control, "Contact tracing for COVID-19: current evidence, options for scale-up and an assessment of resources needed," 5 May 2020. [Online]. Available: https://www.ecdc.europa.eu/en/publications-data/contact-tracing-covid-19-evidence-scale-up-assessment-resources. [Accessed 11 March 2021].

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Reference 16

Ferreira, A., Young, T., Methews, C., Zunza, M. and Low, N., "Strategies for partner notification for sexually transmitted infections, including HIV," Cochrane Database of Systemic Reviews, no. 10, 3 October 2013.

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Reference 17

Rapid Investigation Team, Public Health England, "Preliminary investigation into COVID-19 exceedances in Leicester (June 2020)," 29 June 2020. [Online]. Available: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/897128/COVID-19_activity_Leicester_Final-report_010720_v3.pdf.

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Reference 18

Choi, H., Cho, W., Kim, M. H., and Hur, J.Y., "Public Health Emergency and Crisis Management: Case Study of SARS-CoV-2 Outbreak," International Journal of Environmental Research and Public Health, vol. 17, no. 11, p. 3984, June 2020.

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Reference 19

Lee, V., Chiew, C., and Khong, W., "Interrupting transmission of COVID-19: lessons from containment efforts in Singapore," Journal of Travel Medicine, vol. 27, no. 3, p. taaa039, May 2020.

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Reference 20

Marcus, L. and S. o. P. H. Harvard TH Chan, "Assessment of Risks of SARS-CoV-2 Transmission During Air Travel and Non-Pharmaceutical Interventions to Reduce Risk: Phase One Report: Gate-to-Gate Travel Onboard Aircraft," Harvard TH Chan School of Public Health, 2020.

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Reference 21

Li, Y.Y., Wang, J.X., and Chen, X., "Can a toilet promote virus transmission? From a fluid dynamics perspective," Physics of Fluids, vol. 32, no. 6, June 2020.

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Reference 22

Leigh-Hunt, N., Bagguley, D., Bash, K., Turner V., Turnbull, S., Valtorta, N., and Caan, W., "An overview of systematic reviews on the public health consequences of social isolation and loneliness," Public Health, vol. 152, pp. 157-171, November 2017.

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Reference 23

Statistics Canada: Jackie Tang, Nora Galbraith and Johnny Truong, "Insights on Canadian Society: Living alone in Canada," 6 March 2019. [Online]. Available: https://www150.statcan.gc.ca/n1/pub/75-006-x/2019001/article/00003-eng.htm. [Accessed 11 March 2021].

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Reference 24

Thompson A., Anisimowicz Y., Miedema B., Hogg, W., Wodchis, W., and Aubrey-Bassler, K., "The influence of gender and other patient characteristics on health care-seeking behaviour: a QUALICOPC study," BMC Family Practice, vol. 17, no. 38, March 2016.

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Reference 25

US Centres for Disease Control, "Public Health Guidiance for Community-Related Exposure," 1 March 2021. [Online]. Available: https://www.cdc.gov/coronavirus/2019-ncov/php/public-health-recommendations.html. [Accessed 11 March 2021].

Return to footnote 25 referrer

Reference 26

World Health Organization, "Public Health Surveillance for COVID-19: Interim Guidiance," 16 December 2020. [Online]. Available: https://www.who.int/publications-detail/global-surveillance-for-human-infection-with-novel-coronavirus-(2019-ncov). [Accessed 11 March 2021].

Return to footnote 26 referrer

Reference 27

Jones, N., Qureshi, Z., Temple, R., et.al., "Two metres or one: what is the evidence for physical distancing in covid-19?," BMJ, vol. 370, p. m3223, 2020.

Return to footnote 27 referrer

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