Here's How Contact Tracing Will Work on iPhones and Android Phones

We all want to stop the spread of the coronavirus and end the pandemic crisis. Contact-tracing is one way to do this, and Google and Apple are working on a cross-platform contact-tracing system for iPhones and Android smartphones that will be available via official health apps.

This system has not yet rolled out. Google and Apple have only published an application programming interface (API) for it, which public health organizations can use to build apps. But Google and Apple this week provided details on what contact tracing might look like inside the health apps and at the OS level on iOS and Android. Here's what to expect.

Update Your OS and Opt In

Once the contact-tracing system is live, make sure Bluetooth is enabled, update your mobile operating system, and opt in. 

On Android, you'll start by going to Settings > Google > Services, where you'll toggle on the entry for COVID-19 Exposure Notifications.

On iOS, you'll navigate to Settings > Privacy > Health > COVID-19 Exposure Logging and toggle that on.

Install the App and Opt In

Install the CDC app (Android, iOS) or an authorized app from your local health authority. This is where you'll report any sickness. Apple and Google are not releasing apps; they're collaborating to allow these apps to work across iOS and Android to collect data and send out alerts.  

Opt in to exposure notifications. The screenshots below are reference designs Apple and Google are providing to developers as guidance; your app may look slightly different. 

Listening for Beacons

Once you opt in, your phone will "regularly send out a beacon via Bluetooth that includes a random Bluetooth identifier — basically, a string of random numbers that aren’t tied to a user's identity and change every 10-20 minutes for additional protection," according to an FAQ. "Other phones will be listening for these beacons and broadcasting theirs as well. When each phone receives another beacon, it will record and securely store that beacon on the device."

So, as the illustration above demonstrates, your phone will connect to nearby phones—anyone with whom you've been in contact with for at least five minutes—and securely download those devices' data, or keys, to your phone.

Sharing Positive Test Results

If you later come down with COVID-19, open the health app on your phone and log a diagnosis. The phone then uploads the last two weeks' worth of beacon data, and asks for your permission to anonymously share your results and notify others.

Positive Match Alerts

Your phone will periodically download beacons from those who have tested positive for COVID-19. If a beacon uploaded by the sick person matches a beacon saved to your phone, you'll receive an alert. It won't identify the person who contracted COVID-19, but will show an estimate of when you were in contact with them and for how long. What you do next will depend on your local health authorities.

How Will Apple and Google Use This Data?

The apps don't record location data; "random Bluetooth identifiers rotate every 10-20 minutes, to help prevent tracking," the FAQ says. 

Apple and Google will also not have access to identifying information, and "there will be restrictions on the data that apps can collect when using the API, including not being able to request access to location services, and restrictions on how data can be used," the companies say. "There will be no monetization from this project by Apple or Google."

Recommended by Our Editors

What Is Cell Phone Contact Tracing?

Apple, Google Ban GPS Data Collection in COVID-19 Contact-Tracing Apps

Android Users in China Can't Use Google's Coronavirus Contact Tracing App

Google and Apple have also pledged to "disable the exposure notification system on a regional basis when it is no longer needed."

Will it work? Contact-tracing apps have had great success in other countries, but US residents tend to be more concerned with personal choice and privacy than with public benefit and the health of the group, so we'll have to see if people opt in.

There's also the question of testing availability. On Thursday, Apple awarded $10 million from its Advanced Manufacturing Fund to COPAN Diagnostics, which makes sample collection kits for COVID-19 testing.

"This funding will allow COPAN Diagnostics to rapidly accelerate their supply of sample collection kits for hospitals across the United States, expanding production from several thousand today to more than one million kits per week by early July," Apple says. "As part of this effort, Apple will support COPAN Diagnostics’ expansion to a new, larger facility in Southern California, with advanced equipment that Apple is helping design. This expansion is expected to create more than 50 new jobs."

Google has also committed $100 million to COVID relief, including research, economic assistance, and distance learning. 

How to Keep Your Phone Clean and Safe From Carrying Coronavirus