Google is beginning to roll out a system for COVID-19 exposure alerts to Android. The roll out is starting today and will lead to users receiving notifications about potential exposure soon after it happens.
Users won't just start getting exposure alerts for COVID-19 on their Android devices right away though. Before alerts can show up, you need to actually install an app from a local health agency that has created one using the API that Google is making available today.
Then and only then can the system do what it was created and intended to do. Which is to send you an alert when you've come into contact with someone that's been exposed in your area.
Android COVID-19 exposure alerts are anonymous
The main thing to note is that exposure alerts are anonymous. The way the system works is that after you install an app for this purpose, your device will exchange anonymous Bluetooth identifiers with other uses who also have the app installed when you are near each other.
You can have your device transmit a list of people you've come into contact with following exposure. This list is transmitted to the cloud. People's phones can then download a constantly updating list of exposed individuals from their area, where you get an alert if there's a match so you can then contact your local health agencies.
The point of the apps and the system, is to obviously help curb the spread of the virus. Google also makes a point to highlight that none of the identifiers contain any location data information or GPS data.
Exposure notifications are opt-in
You can choose to receive these alerts but you can also disable them at a time of your choosing. Because the notifications are opt-in.
After you install an app from a local health agency, the app will ask you to enable the alerts. If at any point you want to stop receiving them you can just toggle them off. Just like many other optional features in Android.
Your device also needs to be running at least Android 6.0 Marshmallow. Which is most Android devices at this point. If you want to disable the exposure alerts at any time, you should be able to do so from your phone's settings menu after Google sends out the update to Google Play Services that will push this feature into phones.
You should also be able to see how many exposure checks have been made since the beginning of when you opted in to the alerts. Though that could depend on the app you have as each local public health agency will have to create their own. And the provided images which show what the features will look like are just sample images for reference.
Meaning that particular information may not actually make it into a finished app.