Canadian respiratory virus surveillance report: Laboratory data

Update schedule: Data in this report are updated every Thursday. This page was last updated on September 27th, 2024, 10am ET, with data up to and including ... (surveillance week ...).

On this page

• Highlights
• Weekly trends over time
• Geographic trends
• Historical and current weekly activity
• Test and detection tables
• Explore the data
• Understanding the data

Highlights  for the week ending (week )

National respiratory virus laboratory data summary

Weekly trends over time

Figure 1: in Canada Atlantic     Newfoundland and Labrador     Prince Edward Island     Nova Scotia     New Brunswick Quebec Ontario Prairies     Manitoba     Saskatchewan     Alberta British Columbia Territories     Yukon     Northwest Territories     Nunavut by surveillance week, season

Figure 1: Text description

Figure 1: Data guide

• Use the controls to select an area of Canada and a measure of respiratory virus activity to display. Select viruses to compare trends within the area across the current respiratory virus season. Hover over or tap the figure to display weekly values and dates.

Figure 1: Data notes

• Respiratory viruses other than SARS-CoV-2 are only shown at the regional and national levels. Note that some regions do not test for/report on all RVDSS viruses.
• Weekly percent positivity estimates are suppressed (not shown) for the Northwest Territories when the number of weekly COVID-19 tests reported is under 45. For small counts such as this, it is difficult to provide an accurate weekly percent positivity estimate.

Geographic trends

Figure 2: {Select a virus:} for {Select a virus:} by province, territory, or region for the week ending ...

Figure 2: Text description

Figure 2: Data guide

• Use the controls to select a virus and a measure of respiratory virus activity. The map displays selected data for the most recent surveillance week, presenting a geographic comparison of the current situation. Hover over or tap areas to display trends over time.

Figure 2: Data notes

• Different provinces and territories may use different testing practices which can affect indicators such as percentage of tests positive. Interpret with caution.
• Respiratory viruses other than SARS-CoV-2 are shown at the regional and national levels. Note that some regions do not test for/report on all RVDSS viruses.
• Weekly percent positivity estimates are suppressed (not shown) for the Northwest Territories when the number of weekly COVID-19 tests reported is under 45. For small counts such as this, it is difficult to provide an accurate weekly percent positivity estimate.

Historical and current weekly activity

Figure 3: Percentage of tests positive in Canada by surveillance week, comparison of recent respiratory virus seasons

Figure 3: Text description

Figure 3: Data guide

• These figures compare the national weekly percentage of tests positive across recent respiratory virus seasons. Use the controls to select viruses and seasons for comparison. Use the scale buttons to select if all figures are to have the same scale (fixed) or that each figure’s scale is adjusted to fit its data (dynamic).
• Hover over or tap a figure to display weekly values and dates. Note that dates are only presented for the current season. Data are aligned across seasons by surveillance week; these weeks do not include the exact same days of the year across seasons, but do not differ by more than 7 days. For additional information, please see technical notes.

Figure 3: Data notes

• Testing practices are prone to change over time, which can affect indicators such as percentage of tests positive. Direct comparisons across seasons should be made with caution.
• RVDSS integrated SARS-CoV-2 surveillance at the beginning of the 2022-2023 season. No prior data are available for comparison.

Test and detection tables

Table 1: Respiratory virus tests and positive detections for the by for

Table 1: Data guide

• Use the controls to view lab test and detection data in greater detail for selected respiratory viruses. Data can be viewed by reporting laboratory, the level at which data are reported to RVDSS, or can be aggregated and viewed by province and territory or region. Select to view data for the current surveillance week or for the season-to-date.
• Adjust the table by selecting viruses and by using the filter to select specific reporting laboratories to view.

Table 1: Data notes

• Data represent surveillance data available at the time of analysis. Delays in the availability and reporting of data may cause data to change retrospectively.
• "N/A" is used to identify data that is not available. Data may be unavailable if it was not reported for the current surveillance week. Alternatively data may be unavailable if a reporting laboratory does not collect/report data for specific viruses.
• Some public health laboratories in Canada perform subtyping on influenza specimens from other laboratories. When identified, these subtype detections are not included in total influenza A detection counts; in these instances, total influenza A detection counts may not equal the sum of influenza A subtype detections. Total influenza A and B positive counts are used to calculate percentage of tests positive.
• Results from British Columbia comprise of specimens from the following sites: Children's and Women's Hospital Laboratory, Fraser Health Medical Microbiology Laboratory, Island Health, Providence Health Care, Vancouver Coastal Health sites, Victoria General Hospital, BCCDC Public Health Laboratory, Interior Health Authority sites, and Northern Health Authority sites.
• Abbreviations:
  • A(H1)pdm09: Influenza A(H1)pdm09
  • A(H3): Influenza A(H3N2)
  • A(UnS): Influenza A(Unsubtyped)
  • EORLA: Eastern Ontario Regional Laboratory Association
  • N/A: Not available
  • PHOL: Public Health Ontario Laboratory
  • UHN: University Health Network

Explore the data

Figure 4: , stratified by , scale

Figure 4: Text description

Figure 4: Data guide

• Use the controls to explore data from the current season. Explore measures of respiratory virus activity with flexibility to compare measures by virus or by region.
• Select the regions and viruses to be displayed. Use the controls to display figures separated by region or separate by virus.
• Select the measure of respiratory virus activity to be displayed and select whether all figures are to have the same scale (fixed) or if each figure’s scale is to be adjusted to fit its data (dynamic).

Figure 4: Data notes

• Different provinces and territories may use different testing practices which can affect indicators such as percentage of tests positive. Interpret with caution.

Understanding the data

In this section

• Abbreviations
• Data source
• Data use
• Technical notes

Abbreviations

A(H1N1)pdm09

Influenza A(H1N1)pdm09

A(H3)

Influenza A(H3N2)

A(UnS)

Influenza A(Unsubtyped)

ADV

Adenovirus

COVID-19

Coronavirus disease 2019

EORLA

Eastern Ontario Regional Laboratory Association

EV/RV

Enterovirus/Rhinovirus

HCoV

Human coronavirus 229E/OC43/NL63/HKU1

HMPV

Human metapneumovirus

HPIV

Human parainfluenza virus

N/A

Not available

PHOL

Public Health Ontario Laboratory

RSV

Respiratory syncytial virus

RVDSS

Respiratory Virus Detection Surveillance System

SARS-CoV-2

Severe acute respiratory syndrome coronavirus 2

UHN

University Health Network

Data source

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.

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. Respiratory testing algorithms vary by province or territory.

Data use

RVDSS laboratory data are one of the main surveillance components for monitoring respiratory virus activity in Canada. Weekly percentage of tests positive (also referred to as percent positivity) is the primary indicator used to assess repiratory virus transmission trends over time and place. This indicator is calculated from submitted RVDSS data as:

$\mathrm{Weekly\; percentage\; of\; tests\; positive\; (\%)}=\frac{\mathrm{Number\; of\; positive\; detections\; in\; a\; week}}{\mathrm{Number\; of\; tests\; in\; a\; week}}x\; 100\%$

RVDSS percent positivity data are used to determine the start and end of seasonal influenza epidemics.

RVDSS laboratory data are also used to fulfil Canada’s international respiratory virus surveillance responsibilities. Each week, we submit aggregate data to the World Health Organization's (WHO) RespiMart and to the Pan American Health Organization (PAHO) for inclusion in their weekly situation reports on respiratory viruses.

Technical notes

Data in this report represent surveillance data available at the time of analysis. Delays in the availability and reporting of data may cause data to change retrospectively.

RVDSS does not capture all respiratory virus testing in Canada.

Data are aggregated by RVDSS surveillance weeks. This allows the comparison of current data to historical data. Surveillance weeks begin on Sunday and end on the following Saturday.

This report only presents detailed data for the current respiratory virus season. Surveillance for each respiratory virus season starts on week 35 of a calendar year and ends on week 34 of the following calendar year. This 1-year period begins and ends around the end of August. Detailed data from previous respiratory virus seasons can be accessed through the archives section of this report.

• Calendar of surveillance weeks (current season)
• Respiratory virus report archives

RVDSS integrated SARS-CoV-2 surveillance at the beginning of the 2022-2023 season; no prior data are available for historical comparison.

Differences in RVDSS indicators across jurisdictions can reflect differences in testing algorithms and reporting, as well as true differences in virus activity. Use caution when comparing indicators across jurisdictions. SARS-CoV-2 testing and reporting differences were greatest when SARS-CoV-2 was first included in the RVDSS, but are expected to diminish over time.

N/A is used to identify data that is not available. Data may be unavailable if it was not reported for the current surveillance week. Alternatively data may be unavailable if a reporting laboratory does not collect/report data for specific viruses.

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.

Unless otherwise specified, the term influenza includes influenza A and influenza B positive detections.

Some public health laboratories in Canada perform subtyping on influenza specimens from other laboratories. When identified, these subtype detections are not included in total influenza A detection counts; in these instances, total influenza A detection counts may not equal the sum of influenza A subtype detections. Total influenza A and B positive counts are used to calculate percentage of tests positive.

Changes to testing practices during the COVID-19 pandemic caused changes to RVDSS indicators (also referred to as ‘measures of respiratory virus activity’). Counts of tests and positive detections have increased due to higher testing levels. Percentage of tests positive is likely biased downwards due to the addition of SARS-CoV-2 to testing panels. Due to these changes, seasonal data from before the COVID-19 pandemic are not presented in this report.