COVID Alert performance metrics

The COVID Alert app was updated in February 2021, to collect metrics to help improve the Government of Canada's understanding of the app's use and impact while preserving the app's privacy-first approach.

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About COVID Alert

The Government of Canada launched COVID Alert, a national exposure notification app on July 31, 2020. Exposure notifications were one more tool that we could use to help limit the spread of COVID-19.

Unlike contact tracing apps, as used in some other countries, COVID Alert did not have the ability to track a user’s location and did not collect any personally identifiable information.

When a user downloaded the app and consented to its various functions, their mobile device exchanged random codes with other app user's smartphones. This differed from contact tracing apps, which access a device's location data and report it to public health authorities.

Data privacy and limitations

COVID Alert was designed to protect the privacy of Canadians. No personally identifiable data was collected and no data can be connected to a specific device or sets of devices. Given the privacy-first design of the app, some limitations were expected in the availability of app metrics.

The aggregate data collected from COVID Alert represented activity happening within the app. The in-app metrics began to be available as of late February 2021, when they were introduced into the app, and as technical fixes were completed for the different metrics.

Since in-app metrics were rolled out, a discrepancy was identified between the number of active users taken from Apple and Google app store data and the number of phones sending metrics data to the COVID Alert server. It was confirmed that a number of Android phones running the app were not doing background checks, which was required to trigger exposure notifications and to send metrics data. This incomplete background check may be because of intentional or unintentional user behaviour like a device not being connected to data, having Bluetooth off or having turned the app off.


One-time keys

When a public health unit confirmed positive test results, the provincial and territorial public health unit generated a one-time key (OTK) and provided it to the COVID Alert user. The COVID Alert app user then entered the one-time key in the app. When a user entered an OTK in the app, this triggered a notification to inform others of possible exposure.

Across Canada, 69% of users with an OTK have entered it into the app.

Table 1 – One-time keys generated by provinces and territories and entered by user (Data from October 3, 2020 to May 31, 2022)
Province or Territory OTKs generated OTKs entered by users OTKs entered as percentage of generated
Newfoundland and Labrador 670 559 83%
Nova Scotia 262 206 79%
New Brunswick 366 226 62%
Quebec 7,255 6,923 95%
Ontario 73,185 49,119 67%
Manitoba 4,253 2,771 65%
Saskatchewan 5,562 3,287 59%
Total 91,592 63,117 69%

Source consulted: June 2, 2022

Server data

Note: Data is suppressed for PEI and NWT to ensure privacy; however, their data is included in the total. It also includes OTKs entered by users who have not selected a province or territory in the app.

From October 3, 2020 to May 31, 2022, 91,592 one-time keys were generated by the on-boarded provinces and territories and 63,117 keys were entered. These metrics, and total downloads, were the only counts collected in a centralized server.


Other COVID Alert metrics, such as notifications and OTKs entered in the app after a notification were collected in aggregate since February 2021.

Since data became available in late February 2021, COVID Alert sent more than 456,359 notifications.

Table 2 – Summary of one-time keys and notifications (Data from October 3, 2020 to May 31, 2022)
Date OTKs generatedFootnote a OTKs entered by usersFootnote aFootnote b Notifications sentFootnote c OTKs entered by users after notificationFootnote c
October 3, 2020 to February 24, 2021 24,507 19,407 No data No data
February 25, 2021 to March 31, 2021 5,247 3,711 8,305 No data
April 1, 2021 to May 31, 2022 61,811 39,999 448,054 2,446
Total 91,592 63,117 456,359 2,446
Footnote a

Server data

The number of one-time keys generated and entered was provided by the server, which is why data on these metrics was available prior to the addition of in-app metrics in February 2021.

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Footnote b

There were an additional 698 OTKs that were entered between the launch of the app (July 31, 2020) and the beginning of the server-side metric data (October 3, 2020). These OTKs entered were not included in the server data repository.

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Footnote c

In-app data

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Data available starting in April 2021 shows that COVID Alert notifications have helped identify at least 2,446 confirmed cases of COVID-19. We know this minimum number based on how many people received an exposure notification and later entered a one-time key in the app after testing positive for COVID-19.

Table 3, below, shows the total one-time keys entered after an exposure notification was received as a percent of total one-time keys recorded from April 1, 2021 to May 31, 2022. One-time keys entered after notification account for approximately 7% of total one-time keys recorded.

Table 3 – One-time keys before and after an exposure notification (Data from October 3, 2020 to May 31, 2022)
Month Total OTKs enteredFootnote a Number of notifications sentFootnote b OTKs entered after app notificationFootnote b OTKs entered after app notification (as % of total OTKsFootnote c)
October 2020 2,415 No data No data No data
November 2020 3,857 No data No data No data
December 2020 5,456 No data No data No data
January 2021 5,610 No data No data No data
February 2021 2,387 695Footnote 1 No data No data
March 2021 3,393 7,610 No data No data
April 2021 6,495 35,207 416 8.8%
May 2021 3,149 26,410 198 7.1%
June 2021 504 3,910 24 5.3%
July 2021 150 1,199 1 0.7%
August 2021 559 4,768 18 3.5%
September 2021 797 8,622 24 3.3%
October 2021 677 7,035 40 6.3%
November 2021 869 11,179 38 4.6%
December 2021 12,252 163,855 1,113 9.6%
January 2022 8,347 101,767 385 4.9%
February 2022 1,405 15,539 30 2.3%
March 2022 1,671 25,236 62 3.9%
April 2022 2,326 31,547 74 3.3%
May 2022 798 11,780 19 2.6%
Total 63,117 456,359 2,443 6.8%
Footnote a

Server data

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Footnote b

In-app data

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Footnote c

Note: This percentage is calculated using a consistent data source. It is based on OTK data from in-app metrics because OTKs after a notification were only available from in-app metrics. The count for total OTKs entered from in-app data is slightly lower than the server data (15-20%). This is due to phones that have not upgraded to the version of the app that contains the in-app metrics.

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Footnote d

Number of notifications are available starting from February 25, 2021.

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For more information, please visit Canadian Digital Services’ GitHub data repository.

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