Canadian respiratory virus surveillance report: COVID-19
Weekly overview of key trends in COVID-19 activity in Canada.
- Last updated: 2024-11-01
Update schedule: Data in this report are updated every Friday. This page was last updated on September 27th, 2024, 10am ET, with data up to and including ... (surveillance week ...).
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Highlights for the week ending (week )
COVID-19 activity levels
Figure 1: Map of COVID-19 activity by province/territory in Canada, week (week ending )
Figure 1: Text description and notes
| Province or territory | Overall COVID-19 activity level | Overall change |
|---|
- COVID-19 activity level assessments are based on data from provincial and territorial partners . For more information on public health recommendations or risk assessments, please refer to the provincial and territorial websites. More information on COVID-19 activity levels, how they are calculated, and relevant data caveats, can be found in the Technical Notes.
COVID-19 activity level technical notes and definitions
COVID-19 activity levels are based on data from provincial and territorial (PT) partners. National COVID-19 activity levels were developed with PT partners to monitor COVID-19 activity at the national and PT levels using a standard set of core indicators. Based on these indicators, COVID-19 activity can range from level 0 (no activity) to level 4 (high activity). They are presented with the overall change (increase, decrease, no change) from the previous week.
Indicators: The overall COVID-19 activity level is assessed based on the following three indicators, where available:
- Weekly percent positivity
- Weekly number of lab positive tests / Weekly total number of tests x 100.
- Note: This indicator is only incorporated into overall assessment if the testing rate is greater than or equal to 100 tests per 100,000 population per week. This indicator is used to provide information about overall activity level and trajectory.
- Weekly long term care facility (LTCF) outbreaks per 1,000,000 population
- Weekly number of LTCF outbreaks / Total population in jurisdiction x 1,000,000.
- Note: This indicator is used to provide information on overall activity level and trajectory.
- Weekly COVID-19 wastewater trajectory
- Trajectory of weekly COVID-19 wastewater viral levels compared to the previous week.
- Note: This indicator is used to provide information on overall trajectory only.
Assessment process: The overall COVID-19 activity level is assessed based on the following three indicators, where available:
- Each indicator is assigned a level ranging from ‘no activity detected’ (level 0) to ‘very high activity’ (level 4), based on established thresholds (increasing, decreasing, or no change) of a change of 10% or more compared to the previous week.
- Overall activity level is then determined using the average level of the available indicators (rounding to the nearest whole number).
- Overall trajectory, or the direction of change (based on 10% change compared to the previous week), is calculated based on the mode of the trajectories from available indicators.
Data assessment caveats: The overall COVID-19 activity level is assessed based on the following three indicators, where available:
- This information is based on data from PT partners. For more up to date information and for public health recommendations or risk assessments, please refer to PT websites.
- Weekly changes in tests performed, and LTCF outbreaks reflect changes in counts between the end of the latest epidemiological week and the end of the previous epidemiological week. Data are updated on an ongoing basis and are subject to change.
- PT testing practices, data sources and reporting to PHAC vary across jurisdictions.
- There may be variations in the COVID-19 activity across a jurisdiction. It’s possible that if there are outbreaks occurring in one area, it may result in a higher level of COVID-19 activity. Weekly activity level assessments are intended to provide a high-level overview of COVID-19 spread using standard indicators at the national and PT level. They may not reflect the true extent of geographic spread of COVID-19.
Laboratory-confirmed detections
Figure 2: Number of reported COVID-19 detections and percentage of tests positive in Canada by report week
Figure 2: Text description
COVID-19 variants in Canada
All viruses change over time, including SARS-CoV-2, the virus that causes COVID-19 disease. These changes are called mutations and viruses with mutations are called variants. A percentage of all positive COVID-19 PCR test results in Canada undergo whole genome sequencing. Sequencing tells us which variant is involved in a specific case of COVID-19.
About variants and lineages
Many variants are being tracked across Canada and around the world. Some variants are classified as:
- variant under monitoring (VUM)
- is being monitored to assess its mutations and characteristics
- variant of interest (VOI)
- has mutations or characteristics of interest and is being monitored to see if they pose significant risk to public health
- variant of concern (VOC)
- has mutations and characteristics that are significant to public health
Occasionally, a person may be infected with 2 different variants at the same time. The genetic material from each variant can mix to form a combined variant, referred to as a recombinant virus. Recombinant viruses inherit the properties of their parents, which can change how the virus behaves. The scientific names of the variants discussed below that start with “X” are known as recombinant variants (for example, XBB.1).
Some viruses evolve quickly, making many variants over time. To simplify tracking, variants are grouped into lineages, which are variants that share recent ancestry. For example, variant BA.1 (also known as the original Omicron variant) had several offspring lineages such as BA.1.1 and BA.1.1.1.
As of March 2023, the World Health Organization (WHO) assigns Greek letters only to VOCs, while VOIs and VUMs are referred to using established scientific nomenclature systems. There are no current VOCs in Canada because Omicron has moved to the “de-escalation” category.
A variant is “de-escalated” once it becomes clear that the variant does not pose an elevated risk to the population or that it is being replaced by newer variants." Add sub heading "Recent variants" and under add: "This graphic shows the percentage mix of variant lineages detected in Canada through whole genome sequencing over the last 10 weeks. Each week is represented by a bar. The most dominant lineage in each week has the largest block of that week’s bar.
The first 8 weeks of the figure reflect the actual data from the National Genomic Database. The last 2 weeks reflect the nowcasted estimates. Nowcasting uses statistical models to estimate the current situation based on earlier trends. It provides estimates for the most recent weeks when the data is still accumulating and is therefore incomplete.
For more detailed information about how nowcasting works, refer to Nowcasting methods.
The numerical values for each lineage are shown in the legend, along with predictive intervals. Predictive intervals are ranges (for example, 16-19%) that indicate the confidence of each estimate. The narrower the range, the more confident we are that the prediction is accurate."
Figure 3: COVID-19 variants in Canada, breakdown by week Updated: May 28, 2024, 9 am ET download COVID-19 weekly variant breakdown data in .csv format
You can see the numbers for each date by hovering over, tabbing to, or long-pressing any of the bars. To see a specific variant or variant grouping, click or press return. Repeat to restore the complete graph. Click on the name of the variant in the legend to reveal or hide any descendants or offshoots.
* Includes all descendant lineages, unless otherwise specified.
† More data is needed to estimate the growth and proportion of this lineage with more certainty.
Figure 3: Text description
Weekly variant breakdown
Percentage of COVID-19 cases identified through whole genome sequencing, presented by variant and by week of sample collection.
| Variant grouping | Variant |
|---|
* Includes all descendant lineages, unless otherwise designated.
† The growth rate of this lineage is likely to decrease once more data accumulates.
Contributing laboratories
- National Microbiology Laboratory (NML) - supplemental sequencing for all provinces and territories
Figure 3: Data notes
- Important note: When a new lineage first emerges, its detection levels will be too low to include it in the nowcasting model. Once it is included, data will still be limited at first and its growth and overall proportion will be estimated with lower confidence. As data rolls in, the accuracy and precision of the predictions improve and the predictive interval shrinks. During periods of slow data collection, the overall proportions may be skewed and the predictions may be less accurate. Under such conditions, interpret the model projections with caution.
- It takes time to collect, sequence and process viral genomes, so there is often a period of 2 to 3 weeks where data are still being processed. We use a nowcasting model to estimate the current variant proportions for this period.
- * Includes all descendant lineages, unless otherwise specified.
- † More data is needed to estimate the growth and proportion of this lineage with more certainty.
- The first 8 weeks of the figure reflect the actual data from the National Genomic Database. The last 2 weeks reflect the nowcasted estimates. Nowcasting uses statistical models to estimate the current situation based on earlier trends. It provides estimates for the most recent weeks when the data is still accumulating and is therefore incomplete. For more detailed information about how nowcasting works, refer to Nowcasting methods.
- The numerical values for each lineage are shown in the legend, along with predictive intervals. Predictive intervals are ranges (for example, 16-19%) that indicate the confidence of each estimate. The narrower the range, the more confident we are that the prediction is accurate.
COVID-19 laboratory-confirmed detections: Data notes
Laboratory-confirmed COVID-19 detections
- Data are collected through the Respiratory Virus Detection
Surveillance System (RVDSS). RVDSS is a long-standing laboratory
surveillance system consisting of provincial, territorial, and regional
public health laboratories and some hospital laboratories. There are
reporting laboratories in all provinces and territories, but not all
respiratory virus testing in Canada is captured through RVDSS.
Laboratories report data for up to 8 respiratory viruses:
- SARS-CoV-2 (the virus that causes COVID-19)
- Influenza (commonly referred to as the flu)
- Respiratory syncytial virus (RSV)
- Human parainfluenza virus
- Adenovirus
- Human metapneumovirus
- Enterovirus/rhinovirus
- Human coronavirus 229E/OC43/NL63/HKU1 (does not include SARS-CoV-2)
- Laboratories perform molecular testing for these viruses and report the number of tests and positive detections for each virus each week throughout the year.
- There are reporting laboratories in all provinces and territories, but not all respiratory virus testing in Canada is captured through RVDSS.
- Most tests are conducted on:
- acute respiratory infection cases at emergency departments
- hospitalized severe acute respiratory virus infection cases
- outbreak cases
- Outpatient cases with symptoms of respiratory virus infection may be targeted, but testing is typically limited to people at higher risk.
- RVDSS integrated SARS-CoV-2 surveillance at the beginning of the 2022-2023 season; no prior data are available for historical comparison.
- Respiratory virus trend assessments (increasing/decreasing/stable) are currently based on PHAC subject matter expert interpretation of week-to-week changes in respiratory virus laboratory detections and percent positivity. Set thresholds for trend assessment are under development.
Laboratory indicators
- Number of detections by week for COVID-19 (National)
- Number of tests performed by week for COVID-19 (National)
- Percentage of laboratory tests positive by week for COVID-19 (National)
Antigenic characterization
Changes in circulating SARS-CoV-2 viruses are monitored by antigenic characterization. In order to assess vaccine relatedness, NMLB antigenically characterized circulating strains using ferret-derived antisera raised against the current vaccine strain, KP.2.
Table 1: Lineages with low antigenic reactivity against KP.2 antisera
Antiviral susceptibility
The National Microbiology Laboratory Branch (NMLB) also assesses the antiviral susceptibility of SARS-CoV-2 viruses received from Canadian laboratories.
Syndromic
Figure 4: Percentage of FluWatchers reporting cough and fever in Canada, season 2024-2025, compared to previous seasons
Figure 4: Text description
Figure 5: Percentage of tests positive for COVID-19, influenza, and RSV compared to the percentage of FluWatchers reporting cough and fever in Canada, 2023-2024 season
Figure 5: Text description
Outbreaks
Figure 6: Number of new test-confirmed outbreaks associated with COVID-19 in Canada by setting and report week
Figure 6: Text description
Figure 7: Cumulative proportion of test-confirmed outbreaks of COVID-19 by setting in Canada in the 2024-2025 season
Figure 7: Text description
COVID-19 outbreaks section: Data notes
Test-confirmed COVID-19 outbreaks
Outbreaks of test-confirmed COVID-19 in high-risk settings (long-term care facilities, acute care facilities, retirement facilities, remote and/or isolated communities, and other settings) are reported from provincial and territorial public health departments. The distribution of outbreaks by setting provides a timely, sensitive measure of early COVID-19 activity that is scalable from a local to national level. It provides evidence of the burden of COVID-19 within various closed settings and at-risk populations.
- Not all provinces and territories provide outbreak data.
- 11/13 PTs, representing approximately 97% of the population in Canada, provide outbreaks data for COVID-19.
- Note: the number of participating PTs may fluctuate over the course of the season.
- Outbreak definitions and facility types may not be uniformly applied across all regions/PTs but serve as a rough operational definition across jurisdictions in Canada.
- Not all PTs conduct surveillance in all facility types.
- Not all jurisdictions within a PT report outbreaks.
- Due to data collection practices in some PTs, some outbreaks cannot be confirmed to be due to COVID-19; thus, the terms “associated with” or “detected” are used when reporting outbreaks nationally.
Indicators
- Number of test-confirmed COVID-19 outbreaks
Definitions
| Setting | Setting definition | Outbreak definition |
|---|---|---|
| Long-term care facilities | Facilities that provide living accommodation for people who require on-site delivery of 24 hour, 7 days a week supervised care, including professional health services, personal care and services such as meals, laundry and housekeeping or other residential care facilities. Provincial/territorial public health is responsible for outbreak management under provincial legislation for these facilities. | Two or more test-confirmed cases of COVID-19 which are epidemiologically linked to a specific setting or location. Test-confirmed cases include positive COVID-19 results from nucleic acid amplification tests (NAAT) or rapid antigen tests (RAT). |
| Acute care facilities | Publicly funded facilities providing medical and/or surgical treatment and acute nursing care for sick or injured people, through inpatient services. (i.e. hospitals including inpatient rehabilitation and mental facilities). | Two or more test-confirmed cases of COVID-19 which are epidemiologically linked to a specific setting or location. Test-confirmed cases include positive COVID-19 results from nucleic acid amplification tests (NAAT) or rapid antigen tests (RAT). |
| Retirement facilities | A residential complex, or part of a residential complex that is: occupied primarily by persons who are 65 years of age or older, occupied by at least six persons not related to the operator, AND where the operator makes at least two care services available to residents. The residential complex provides accommodation, meals, housekeeping, linen and recreational services for residents that are able to move independently or with the assistance of one other person. Residents are medically and physically stable, who may be living with physical disability, mental health diagnoses, or mild dementia. Example facilities:
|
Two or more test-confirmed cases of COVID-19 which are epidemiologically linked to a specific setting or location. Test-confirmed cases include positive COVID-19 results from nucleic acid amplification tests (NAAT) or rapid antigen tests (RAT). |
| Remote and/or isolated communities | A community that is physically and/or socially separated from the surrounding population. For example, communities that are geographically isolated due to limited transportation links. | Two or more test-confirmed cases of COVID-19 which are epidemiologically linked to a specific setting or location. Test-confirmed cases include positive COVID-19 results from nucleic acid amplification tests (NAAT) or rapid antigen tests (RAT). |
| Other | Any other locations/facilities not previously identified in which an outbreak of the influenza, RSV, COVID-19 or ILI occurs. Example facilities:
|
Two or more test-confirmed cases of COVID-19 which are epidemiologically linked to a specific setting or location. Test-confirmed cases include positive COVID-19 results from nucleic acid amplification tests (NAAT) or rapid antigen tests (RAT). |
Severe outcomes
Figure 8: of COVID-19-associated hospitalizations by age-group and surveillance week, Canada, participating provinces and territories
Figure 8: Text description
Covid-19 severe outcomes section: Data notes
Provincial/territorial severe outcomes surveillance
Hospitalizations, ICU admissions, and deaths associated with COVID-19, by age or age group, are reported from provincial and territorial public health departments.
- Not all provinces and territories provide severe outcomes data.
- 9/13 PTs, representing approximately 25% of the population in Canada, provide data for COVID-19-associated hospitalizations and ICU admissions.
- 10/13 PTs, representing approximately 63% of the population in Canada, provide data for COVID-19-associated deaths.
- Note: the number of participating PTs may fluctuate over the course of the season.
- Hospital admissions and/or deaths don't have to be directly caused by COVID-19; a positive test is sufficient for reporting.
- PT definitions for COVID-19 deaths vary by jurisdiction
Indicators
- Cumulative rate (per 100,000 population) of COVID-19-associated hospitalizations by age-group, by week.
- Weekly rate of COVID-19-associated hospitalizations by age-group, by week.
- Cumulative number of COVID-19-associated hospitalizations, ICU admissions, and deaths.
- Cumulative rate (per 100,000 population) of COVID-19-associated ICU admissions, by week.
Definitions
- Hospitalizations
- Any person admitted to hospital with laboratory-confirmed COVID-19.
- ICU admissions
- Any person with laboratory-confirmed COVID-19 admitted to an intensive care unit (ICU) or requiring mechanical ventilation.
- Deaths
- A death occurring in any person with laboratory-confirmed COVID-19 with no period of complete recovery between illness and death.
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COVID-19 wastewater surveillance dashboard
Trend data about the levels of COVID-19 in the wastewater.
COVID-19 vaccination
Number of COVID-19 vaccine doses that have been administed in Canada.
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