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.

On this page

• About COVID Alert
• Data privacy and limitations
• Performance

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.

Performance

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.

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.

Notifications

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.

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.

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