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Health Canada's COVID Alert App

On July 31st, the federal government announced the launch of COVID Alert—a smart phone application that alerts users if they have been exposed to someone who tested positive for COVID-19, and provides the appropriate steps to take afterwards.

The app

COVID Alert is available for iOS and Android. The app can be downloaded here for iOS users and here for Android users.

In combination with mask-wearing and social distancing, informing people that they have been exposed to COVID-19 and should get tested immediately will help prevent the spread of the virus. The app is currently optional, but the more people that download the app, the more effective this system will be.

Privacy and how it works

The app was beta tested by almost 6,000 people and aims to be very user-friendly. The Government of Ontario website explains how the app works:

  • Users download the app to their phone, which will run in the background as they go about their day. The app uses Bluetooth, a wireless way to transfer data between two devices, to determine if two users—one of whom has tested positive for the virus—have been within 2 metres of each other for more than 15 minutes.

  • The app trades random codes with users nearby every 5 minutes. These codes are stored for 2 weeks. Both the app developers and the Canadian government have emphasized that privacy was a very big priority; the random codes can not be traced back to the user.

Privacy commissioner Daniel Therrien has stated

[The app has] exceptionally strong encryption and cryptographic hashing functions.

There will be no sharing of location, name, contact information, health history or anything of the sort with other users.

  • When the phone reconnects to wifi, the codes that were stored will be compared to codes of people that have tested positive for the virus. If there is a match, the app sends the user a notification that they may have been exposed to the virus and what their next steps should be (i.e. get tested, stay home until the results come back, and follow the test instructions).  

  • If a user tests positive, they will be able to anonymously report it to the app to notify other users, protecting their communities and their identity at the same time.

*While the app itself does not share any information, users may be able to be identified if they live in remote areas and/or small communities through process of elimination. Additionally, IP addresses are stored and may be used to facilitate legal investigations, if need be.

A look inside the app

Here is a preview of what COVID Alert looks like on your device.

COVID Alert mobile app from the Government of Canada (Government of Ontario)

More information

App developers are looking for ways to maximize the app’s accuracy. This includes finding a way to have the app work well even when phone signals are obstructed which, for example, may occur when the device is deep in a bag.

The app was developed in Ottawa and currently works only in Ontario. However, in other provinces, it still may be useful to keep the app downloaded; although there is no code matching feature, the app still allows users to be notified when others in the area report their tests.

Justin Trudeau plans to use the app in Atlantic Canada and other areas in Canada soon. 

As of August 5th, the app has been downloaded 1.3 million times, but considering the fact that Ontario has a population of about 15 million people, it needs much more users for it to truly be effective! Please download the app if you can to protect yourself and your community!

Download the COVID Alert mobile app here for iOS users and here for Android users.


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Article Contributors: Linda Duong, Victoria Huang