COVID-19 epidemiology update: Testing and variants:
- Last updated: 2023-01-26
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Summary of COVID-19 cases, hospitalizations and deaths, cases following vaccination, testing and variants of concern across Canada and over time. Older versions of this report are available on the archived reports page.
Update schedule: We update ‘Key COVID-19 testing updates’ and ‘Testing in Canada’ every Monday. We update ‘COVID-19 variants in Canada’ every Friday. This page was last updated on .
Changes to COVID-19 testing data source
The data source for COVID-19 testing in Canada changed on December 5, 2022 (see Data notes).
Key COVID-19 testing updates (Last data update )
Notes
Key COVID-19 testing updates: Text description
| Weekly tests reported | {Weekly tests reported} |
|---|---|
| Weekly percent positivity | {Weekly percent positivity} |
Testing in Canada
Figure 1. of COVID-19 by select laboratories, by province or territory (Last data update )
Hover over or tap regions to see cases, and deaths and tests performed in Canada over time. Map data is available in map data.csv format and a data dictionary is available data dictionary.csv format.
Notes
Figure 1: Text description
| Location | Weekly tests reported | Weekly percent positive |
|---|
Data notes
On December 5, 2022, we changed surveillance systems for monitoring laboratory testing of SARS-CoV-2, the virus that causes COVID-19. We now use the Respiratory Virus Detection Surveillance System (RVDSS). Before December 5, we used the System for Analyzing Laboratory Test counts (SALT).
SALT was set up early in the COVID-19 pandemic to monitor daily SARS-CoV-2 testing volumes, and the percent of tests that were positive.
RVDSS is a longstanding surveillance system that collects data from laboratories across Canada on:
- the number of tests performed in participating laboratories and
- the number of positive tests for respiratory viruses
RVDSS mostly collects data from the tests of people who had COVID-19 symptoms or exposures, in order to assess trends in transmission via test positivity. RVDSS allows us to monitor COVID-19 in the context of other respiratory viruses.
The SALT and RVDSS data are not directly comparable.
- RVDSS data on COVID-19 is available starting the week of August 28, 2022 (Week 1 of the 2022/23 influenza season). SALT data are available starting February 1, 2020.
- Test positivity is higher in RVDSS than SALT. This is because tests reported to RVDSS are usually collected for clinical investigations, meaning people with symptoms or exposure to COVID-19, resulting in a higher proportion of positive tests.
- RVDSS presents all data by epidemiological week, while SALT presented daily data. Historical SALT testing data is available.
The number of laboratories participating in RVDSS can vary week to week and across provinces and territories. As a result, the numbers of tests performed cannot be directly compared between provinces and territories. The number of tests reported may be used to add context to interpret weekly percent positivity.
For information on other respiratory viruses circulating in Canada, and comparisons with COVID-19, please visit the weekly RVDSS report.
COVID-19 variants in Canada
All viruses, including COVID-19, change over time. These changes are called mutations, and result in variants of the virus. Not all mutations are of concern. Most do not cause more severe illness. However, some mutations result in variants of concern or variants of interest.
A variant of concern has mutations that are significant to public health. Before a variant of interest is considered one of concern, scientists and public health professionals must determine if the mutations result in an actual change in the behaviour of the virus. For example, it might:
- spread more easily
- cause more severe illness
- require different treatments, or
- reduce vaccine effectiveness
The Public Health Agency of Canada (PHAC) works with provincial and territorial partners and the Canadian COVID-19 Genomics Network (CanCOGeN) to sequence a percentage of all positive COVID-19 test results. Sequencing reveals the genetic code of the virus, which tells us which variant is involved in a specific case of COVID-19. We report the proportion of COVID-19 variants in Canada every week.
We collect evidence to determine if new variants meet the definition for a variant of concern or a variant of interest. Many variants are being tracked across Canada and around the world.
Currently, Omicron and its sub-lineages are the primary variants of COVID-19 circulating in Canada. Evidence demonstrates that Omicron is more transmissible than previous variants of concern.
Previous variants of concern in Canada are as follows:
- Alpha
- Beta
- Gamma
- Delta
Staying up to date with COVID-19 vaccination continues to be one of the most effective ways to protect against serious illness, hospitalization, and death from COVID-19. Canada now has access to two updated bivalent vaccines that are expected to provide better protection against the Omicron variant of concern.
Figure 2. Weekly variant breakdown Updated: December 31, 2021, 4 pm EDT download weekly variant breakdown data in .csv format
The graphic shows the percentage mix of COVID-19 variants detected in Canada through whole genome sequencing, by week of sample collection. 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. Sublineages or offshoots for some variants can be revealed or hidden by clicking on the name of the variant in the legend.
This information is based on whole genome sequencing from surveillance testing in all provinces and territories. In addition to sequencing done by the National Microbiology Laboratory in Winnipeg, data is included from provincial and territorial laboratories.
Sequencing takes from 1 to 3 weeks to complete, so the proportions for recent weeks may change as more data are added. Surveillance in each province or territory is organized and prioritized according to local needs and may change from time to time. Because of differences in local sampling and reporting, the percentages illustrate trends rather than precise measurements.
Weekly variant breakdown
Percentage of COVID-19 cases identified through whole genome sequencing, presented by variant and by week of sample collection.
Figure 2: Text description
| Variant Grouping |
|---|
Note: The shaded columns on the right represent a period of accumulating data.
Contributing laboratories:
- National Microbiology Laboratory (NML) - supplemental sequencing for all provinces and territories
National Microbiology Laboratory (NML) - supplimental sequencing for all provinces and territories
Additional COVID-19 data resources
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COVID-19 wastewater surveillance dashboard
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COVID-19 vaccination
Number of COVID-19 vaccine doses that have been administed in Canada.
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