Canadian respiratory virus surveillance report (CRVSR): About this report

Change in reporting location

A weekly overview of respiratory virus data submitted by laboratories across Canada is available below. Previous summaries of weekly respiratory virus laboratory data collected by the Respiratory Viruses Detection Surveillance System (RVDSS) are available on the archived reports page.

On this page

• Introduction
• General interpretation notes
• Data sources and coverage
• Activity level methods  New
• Surveillance definitions and indicators
• Data stream-specific technical notes
• Provincial, territorial, and international report links

Introduction

The Canadian respiratory virus surveillance report, produced by the FluWatch+ surveillance program, offers a weekly overview of key trends in respiratory viruses, such as influenza (flu), COVID-19, and respiratory syncytial virus (RSV) in Canada.

The FluWatch+ surveillance system receives surveillance data from multiple sources and is made possible through the collaboration of numerous partners across Canada. To learn more about the FluWatch+ surveillance system see the Overview of respiratory monitoring in Canada page.

Each tab in this report contains different information. The "Snapshot" tab contains high level combined trends for COVID-19, influenza, RSV, and other seasonal respiratory viruses. More detailed trends on COVID-19, influenza and RSV can be found on the individual virus tabs. The “Explore the data” tab allows users to download weekly surveillance datasets and choose different views of the data not found in the existing tabs.

General interpretation notes

• Surveillance data reported in the Canadian Respiratory Virus Surveillance Report is used to monitor trends in respiratory virus activity throughout the surveillance period. This includes where and when viruses are circulating, which viruses are present, who is most affected and whether activity is increasing or decreasing. These data are an underestimate and are not intended to reflect the true number of cases of respiratory virus diseases in Canada.
• Due to variations in how data are reported, indicators for COVID-19, influenza and RSV may not be directly comparable. Where data for each virus are presented separately, comparisons between the viruses should be made with caution.
• The data in the Canadian Respiratory Virus Surveillance Report represent surveillance data that are available at the time of writing. Surveillance partners are encouraged to update previously submitted data throughout the surveillance period. All data are preliminary and may change as more reports are received throughout the surveillance period.
• The FluWatch+ program refers to time in surveillance weeks. This allows for the comparison of historical data (e.g. comparing data from week 45 in the 2021-22 period to week 45 of the 2019-2020 period). Data are aggregated by surveillance weeks that run from Sunday to Saturday.
• The surveillance period begins in week 35 of a calendar year (end of August) and ends in week 34 of the following calendar year (end of August). A calendar of surveillance weeks for the current period is available online for reference.
• What do the arrows mean? The arrows (up, down, or stable) show the overall trend for each surveillance indicator. These trends are based on a weekly data, averaged over 4 weeks to smooth out short-term changes/variation (4 week rolling average). The value that defines a change in trend varies depending on the indicator.
  • Laboratory data:
    • Most respiratory viruses: If the percentage of positive tests changes by 0.5% or more from the previous week, the arrow will show an increase or decrease; otherwise a stable trend is assigned.
    • Adenovirus and entero/rhinovirus only: If the percentage of positive tests changes by 1% or more from the previous week, the arrow will show an increase or decrease; otherwise a stable trend is assigned.
  • Hospitalizations: If the rate of positive tests changes by 5% or more from the previous week, the arrow will show an increase or decrease; otherwise a stable trend is assigned.
  • Outbreaks: If the number of outbreaks changes by 5% or more from the previous week, the arrow will show an increase or decrease; otherwise a stable trend is assigned.
  • FluWatchers: If the percentage of participants reporting cough and fever changes by 0.1% or more, the arrow will show an increase or decrease; otherwise a stable trend is assigned.

Data sources and coverage

Data stream	Data source	Coverage (Number of participating provinces and territories)
Aggregate laboratory confirmed detections	Data are collected through the Respiratory Virus Detection Surveillance System (RVDSS). RVDSS is a sentinel laboratory surveillance system consisting of a network of 20 laboratories (includes provincial, territorial, regional and hospital laboratories). There are reporting laboratories in all provinces and territories (PTs) but not all respiratory virus testing in Canada is captured through RVDSS. Laboratories report aggregate 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)	COVID-19, Influenza and RSV: 13 out of 13 PTs
Case-level laboratory detections	Some of the RVDSS provincial, territorial and regional public health laboratories provide age information for COVID-19, influenza and RSV detections.	COVID-19: 12 out of 13 PTs, representing approximately 99% of the population in Canada Influenza: 13 out of 13 PTs, representing 100% of the population in Canada RSV: 12 out of 13 PTs, representing approximately 99% of the population in Canada
Genetic and antigenic characterization of SARS-CoV-2 and influenza, including antiviral resistance	The National Microbiology Laboratory Branch (NMLB) provides data on the genetic and antigenic characterization of SARS-CoV-2 and influenza isolates, as well as their susceptibility to antiviral agents. NML receives a proportion of positive isolates from participating provinces and territories.	Not applicable.
Activity levels	Activity levels are derived based on percent positivity indicator.	100% coverage across PTs for all three viruses.
FluWatchers	Volunteer participants in all provinces and territories	There are volunteers reporting from all PTs across Canada. Further information on number of participants reporting per week by PT can be found in the FluWatchers report.
Outbreaks	Outbreaks of test-confirmed COVID-19, influenza and RSV in high-risk settings are reported from varying provincial and territorial ministries of health.	COVID-19: 11 out of 13 PTs, representing 97% of the Canadian population Influenza: 11 out of 13 PTs, representing 97% of the Canadian population RSV: 9 out of 13 PTs, representing 79% of the Canadian population
PTSOS (Provincial and Territorial Severe Outcome Surveillance)	Hospitalizations, ICU admissions and deaths associated with COVID-19, influenza (influenza type/subtype), or RSV by age or age group are reported by varying provincial/territorial ministries of health, depending on the virus.	COVID-19: 10 out of 13 PTs, representing approximately 83% of the population in Canada, provide hospitalization data for COVID-19; of these PTs, 9 out of 10 provide hospitalization age data, representing approximately 44% of the population. 8 out of 13 PTs, representing approximately 22% of the population in Canada, provide ICU data for COVID-19. All 8 out of 8 PTs provide age data. 10 out of 13 PTs, representing approximately 83% of the population in Canada, provide death data for COVID-19. All 10 out of 10 PTs provide age data. Influenza: 10 out of 13 PTs, representing approximately 83% of the population in Canada, provide data for influenza-associated hospitalizations; 9 out of 10 PTs, representing approximately 44% of the population in Canada, provide hospitalization data for influenza with age information. 8 out of 13 PTs, representing approximately 22% of the population in Canada, provide data for influenza-associated ICU admissions. All 8 out of 8 PTs provide age data. 8 out of 13 PTs, representing approximately 22% of the population in Canada, provide data for influenza-associated deaths. All 8 out of 8 PTs provide age data. RSV: 7 out of 13 PTs, representing approximately 56% of the population in Canada, provide data for RSV-associated hospitalizations. All 7 out of 7 PTs provide age data. 6 out of 13 PTs, representing approximately 17% of the population in Canada, provide data for RSV-associated ICU admissions. All 6 out of 6 PTs provide age data. 6 out of 13 PTs, representing approximately 17% of the population in Canada, provide data for RSV-associated deaths. All 6 out of 6 PTs provide age data.
Pediatric severe outcomes	The SPRINT-KIDS sentinel pediatric (≤18 years) hospital network provides severe outcome monitoring in both the emergency department and inpatient facilities across Canada for COVID-19, influenza and RSV. This network reports detailed case-level information on pediatric hospitalizations, ICU admissions and deaths attributable to COVID-19, influenza or RSV.	15 pediatric hospitals across 8 provinces in Canada (all provinces except New Brunswick and Prince Edward Island).

Activity level methods  New

As of September 2026, FluWatch+ has implemented new methods for deriving activity levels for influenza, COVID-19, and RSV. These methods provide a consistent national approach for classifying respiratory virus circulation across Canada on a weekly basis, based on the data available at the time.

They support comparability across provinces and territories and across viruses throughout the surveillance period. The national activity levels are intended to support national reporting and do not replace or supersede provincial and territorial methods, which may be tailored to local surveillance data, epidemiology, and public health response needs.

Activity levels for influenza, COVID-19 and RSV are derived by applying a method adapted from the Moving Epidemic Method (MEM) to the percent positivity (laboratory) indicator for each virus. The MEM is a statistical method used to identify seasonal epidemic periods and classify disease intensity based on historical surveillance data. It uses data from previous seasons to establish cut points that distinguish different levels of activity, with intensity thresholds derived from peak weekly values during historical epidemic periods.

Modifications to MEM

The following modifications were applied to MEM method in order to adapt it to the Canadian context and use it to categorize how respiratory virus activity evolves throughout the surveillance period.

Modification	Standard MEM approach	Modified approach
Determination of the low cut point value	The lowest cut‑point is statistically derived by establishing historical periods of epidemic activity and calculating the cut-point based on the highest pre/post‑epidemic values.	The lowest cut‑point is empirically selected based on its ability to: capture a high proportion of detections/hospitalizations; delineate in‑ and out‑of‑season activity so pooled values reflect periods of active circulation; and minimize fluctuations in weekly activity levels.
Values used to calculate activity level cut points	Pools only the highest weekly values from each historical season.	Expands the pooled values to include all in‑season observations, defined as values exceeding the lowest cut‑point.
High and very high cut points	Typically uses the 90th percentile (High) and 97.5th percentile (Very high) of pooled peak values.	Uses the 80th percentile (High) and 95th percentile (Very high) of pooled values. Under the standard MEM, the use of higher percentile levels and inclusion of only the highest seasonal values results in very few seasons reaching High levels. The modified approach better reflects the range of in-season activity.

Activity level cut point values

Laboratory percent‑positivity data from the post‑pandemic seasons of 2022–2023 to 2025–2026 were used to derive the activity‑level cut‑point values. Percent positivity and trends vary by jurisdictions, so the cut-points are different for Canada overall and for each province and territory.

Although activity levels used in this report are designed to support comparability across jurisdictions, differences in testing practices, particularly populations tested, may influence percent positivity and the resulting activity levels. These differences should be considered when interpreting comparisons across jurisdictions.

Additionally, these national activity levels may differ from levels reported by provinces and territories, which may use methods tailored to their local surveillance data, epidemiology, and response needs. Differences between federal and provincial/territorial activity levels are expected and should be interpreted in the context of the distinct methodologies and objectives used to assess respiratory virus activity.

Activity‑level methods will be reviewed every year to adjust for additional historical data, performance assessments, and impacts to laboratory testing data.

Activity level values, 2026-2027 surveillance period

Influenza

Jurisdiction	Low	Moderate	High	Very high
Canada	5.0%	10.3%	18.3%	27.9%
BC	5.0%	9.8%	17.8%	27.5%
AB	5.0%	10.5%	18.8%	28.9%
SK	5.0%	11.7%	22.9%	37.6%
MB	5.0%	10.1%	18.6%	29.1%
ON	5.0%	11.1%	19.3%	29.1%
QC	5.0%	11.3%	21.3%	33.9%
NB	5.0%	11.6%	20.0%	29.8%
NS	5.0%	11.5%	19.4%	28.6%
PE	5.0%	14.8%	26.1%	39.6%
NL	5.0%	10.9%	20.2%	31.7%
YT	5.0%	12.2%	23.5%	37.9%
NT	5.0%	14.0%	27.4%	45.1%
NU	5.0%	14.3%	30.0%	51.7%

RSV

Jurisdiction	Low	Moderate	High	Very high
Canada	2.0%	4.5%	7.8%	11.7%
BC	2.0%	5.0%	8.9%	13.5%
AB	2.0%	5.0%	9.3%	14.9%
SK	2.0%	5.5%	11.2%	19.1%
MB	2.0%	4.0%	6.6%	9.5%
ON	2.0%	4.5%	7.8%	11.6%
QC	2.0%	4.6%	8.7%	14.0%
NB	2.0%	5.2%	9.3%	14.3%
NS	2.0%	4.8%	8.4%	12.6%
PE	2.0%	5.5%	12.1%	21.7%
NL	2.0%	4.4%	7.9%	12.1%
YT	2.0%	5.6%	10.5%	16.5%
NT	2.0%	7.7%	18.3%	34.3%
NU	2.0%	6.6%	15.4%	28.8%

COVID-19

Jurisdiction	Low	Moderate	High	Very high
Canada	5.0%	9.3%	14.3%	19.6%
BC	5.0%	10.2%	14.9%	19.7%
AB	5.0%	9.5%	14.1%	18.9%
SK	5.0%	8.0%	11.5%	15.2%
MB	5.0%	10.6%	16.9%	23.8%
ON	5.0%	9.2%	14.2%	19.6%
QC	5.0%	9.8%	15.6%	22.0%
NB	5.0%	9.6%	14.7%	20.1%
NS	5.0%	11.2%	19.0%	27.9%
PE	5.0%	11.2%	18.6%	27.0%
NL	5.0%	11.6%	18.0%	24.7%
YT	3.0%	6.8%	12.0%	18.3%
NT	3.0%	7.1%	12.8%	19.8%
NU	3.0%	6.1%	9.8%	13.9%

Surveillance definitions and indicators

Data stream	Definitions	Indicators	Indicator calculations
Laboratory detections (includes aggregate and case-level)	SARS-CoV-2 detection: Identification of SARS-CoV-2 through a positive test result from laboratory-based nucleic acid amplification tests (NAAT), point-of-care NAAT or antigen tests, or by evidence of infection demonstrated by viral-specific antibodies, seroconversion, or a significant rise in viral-specific antibody titers. Influenza detection: Identification of influenza virus through a positive result from viral culture, immunoassay, or nucleic acid amplification tests (NAAT). RSV detection: Identification of respiratory syncytial virus (RSV) through a positive result from polymerase chain reaction (PCR), direct fluorescent antibody (DFA) assay, or tissue culture.	Aggregate: Number of detections by week by virus Percentage of laboratory tests positive by week by virus	Numerator: weekly number of virus detections Denominator: total weekly number of specimen tested
		Case-level: Cumulative and weekly number of SARS-CoV-2, influenza and RSV detection by age group, type and subtype (where applicable)	Not applicable
Genetic and antigenic characterization of SARS-CoV-2 and influenza, including antiviral resistance	SARS-CoV-2 variant: 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.	Not applicable	Not applicable
FluWatchers	Not applicable	Weekly percentage of FluWatchers participants reporting cough and fever.	Numerator: weekly number of participants reporting cough and fever. Denominator: total weekly participants reporting.
Outbreaks	Outbreak settings: Long-term care settings: 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. 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). 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: retirement homes retirement residences senior living facilities designated supported living facilities (occupied primarily by persons who are 65 years of age or older). 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. Other settings: Any other locations/facilities not previously identified in which an outbreak of the influenza or ILI occurs. Example facilities: assisted living or hospice settings private hospitals/clinics correctional facilities colleges/universities schools/daycares adult education centres shelters workplaces supported living facilities/supportive housing/assisted living facilities for individuals with disabilities group homes residential treatment centres Outbreak definitions: For long-term care, acute care, and retirement facilities: Laboratory-confirmed influenza or RSV outbreak: Two or more cases of ILI within 7 days, and at least 1 laboratory-confirmed case of influenza or RSV in the same setting (on the same floor, or in the same unity or ward). Test-confirmed COVID-19 outbreak: 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). For remote and/or isolated communities and other settings: Laboratory-confirmed influenza or RSV outbreak: Unusual or unexpected number of ILI cases within 7 days and at least 1 laboratory-confirmed case of influenza or RSV. Test-confirmed COVID-19 outbreak: 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).	Cumulative and weekly number of test-confirmed outbreaks by setting.	Not applicable
PTSOS (Provincial and Territorial Severe Outcome Surveillance)	Hospitalizations: Any person admitted to hospital with laboratory-confirmed COVID-19, influenza, or RSV. ICU admissions: Any person with laboratory-confirmed COVID-19, influenza, or RSV admitted to an intensive care unit (ICU) or requiring mechanical ventilation. Deaths: A death occurring in any person with laboratory-confirmed COVID-19, influenza, or RSV with no period of complete recovery between illness and death.	Weekly and cumulative COVID-19, influenza or RSV associated hospitalization rates per 100,000 population.	Numerator: number of COVID-19, influenza, or RSV associated hospitalizations Denominator: sum of population of reporting provinces and territories
Pediatric severe outcomes	Hospitalizations COVID-19:Admissions attributable to acute COVID-19 or resulting complication with detection of SARS-CoV-2 by laboratory-based NAAT, viral specific antibodies, demonstrated seroconversion or diagnostic rise in viral specific antibody titre, or point of care NAAT or antigen test. Influenza:Admissions attributable to influenza infection or a complication of infection (i.e. admitted for influenza or complication of influenza such as febrile convulsion, pneumonia), with laboratory confirmation of influenza by positive culture, positive immunoassay or NAAT. RSV:Admissions attributable to an RSV infection or a complication of infection (i.e. admitted for RSV or complication of RSV such as pneumonia), with laboratory confirmation of RSV by a specific laboratory test, such as PCR, DFA or tissue culture. ICU admissions Any individual meeting the hospitalization definition that was admitted to an intensive care unit (ICU). Deaths Any individual meeting the hospitalization definition that has died in-hospital. Coinfections Hospitalizations and ICU admissions where two or more viruses (among COVID-19, influenza, or RSV) were laboratory confirmed.	Cumulative and weekly number of pediatric hospitalizations, ICU admissions and deaths by age group.	Not applicable

Data stream-specific technical notes

Data stream	Technical notes
Laboratory detections (includes aggregate and case-level data)	Most laboratory 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 for severe outcomes. Testing for RSV and other respiratory viruses has been influenced by the COVID-19 pandemic. Changes in laboratory testing practices may affect the comparability of data to previous seasons. Case-level data represents a portion of laboratory-confirmed detections for all viruses. Respiratory testing algorithms vary by province and territory.
Genetic and antigenic characterization of SARS-CoV-2	Changes in circulating SARS-CoV-2 viruses are monitored by genetic sequencing and modelling. 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. A nowcasting model is used to estimate the current variant proportions for this period. 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.
FluWatchers	Not applicable
Outbreaks	Due to data collection practices in some provinces and territories, some outbreaks cannot be confirmed to be due to a specific virus; thus, the terms “associated with” or “detected” are used when reporting outbreaks nationally. Not all provinces and territories provide outbreak data for all viruses. Read more in the data source and coverage section. Not all provinces and territories conduct surveillance in all facility types Not all jurisdictions within a province or territory report outbreaks. Outbreak definitions and facility types may not be uniformly applied across all regions/provinces and territories but serve as a rough operational definition across jurisdictions in Canada.
PTSOS (Provincial and Territorial Severe Outcome Surveillance)	Not all provinces and territories provide severe outcomes data for all viruses. Read more in the data source and coverage section.
Pediatric severe outcomes	Not applicable

Provincial, territorial, and international report links