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.

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.

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.

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.

Table 2 – Summary of one-time keys and notifications (Data from October 3, 2020 to May 31, 2022)
Date	OTKs generated^{Footnote a}	OTKs entered by users^{Footnote a}^{Footnote b}	Notifications sent^{Footnote c}	OTKs entered by users after notification^{Footnote 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. Return to footnote a referrer 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. Return to footnote b referrer Footnote c In-app data Return to footnote c referrer

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 entered^{Footnote a}	Number of notifications sent^{Footnote b}	OTKs entered after app notification^{Footnote b}	OTKs entered after app notification (as % of total OTKs^{Footnote 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	695^{Footnote 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 Return to footnote a referrer Footnote b In-app data Return to footnote b referrer 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. Return to footnote c referrer Footnote d Number of notifications are available starting from February 25, 2021. Return to footnote d referrer

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

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Date modified:: 2022-06-16

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