You may have heard about the technology developed jointly by Apple and Google to automate contact tracing to help alert people who may have been in proximity to someone infected with COVID-19.

It uses Bluetooth to automatically exchange an anonymous identification key between two people who are near each other. If one person is later diagnosed with COVID-19, they can share that information through an app without revealing their name, location or other personal information,and the app will anonymously notify people who have been near them.

The companies aren’t developing apps, but an application program interface (API) that will make it possible for others to develop apps. They also plan to build this technology into their operating systems, but the companies won’t be doing the tracing. They’ll leave that to public health authorities.

The technology uses Bluetooth Low Energy to communicate an anonymous key that doesn’t contain location or any other identifying information.

How it would work

Two people come into close contact with each other and their phones exchange this key. Neither is given any information about that other person and no information is shared with authorities –not even their locations. If one of those people is later confirmed to have been infected with Covid-19, they would enter that information into the app provided by their health authority and the other person would be notified that they had come into contact with an infected person.  The codes would be stored on the phones which could access a server to see if any of the contacts had indicated they were Covid-19 positive.

This does not replace traditional contact tracing but it does provide an extra tool that can increase the number of people who are notified. Let’s face it, most people don’t remember everyone they came into contact with, especially people they don’t know, like someone they stood next to in a grocery store.

The technology does have its limitations. First, not every infected person knows or may ever know that they are infected. Until we get widespread testing in the United States, there will be many people who are infected but don’t know it because they have no symptoms or mild symptoms that don’t qualify them for getting what are still highly rationed tests. Also, the use of this technology would be voluntary so if you were near someone who was infected, you would have to hope that they had an app turned on and that they entered their Covid-status into the app once they were diagnosed.

And, of course, the connection has to work. Bluetooth is a great technology but it relies on short-range radio waves finding each other. Anyone who’s ever had a Bluetooth speaker or earbuds fair to operate knows that the technology is far from perfect.

But, it’s a good start and I think Google and Apple have been careful to keep the privacy risk to a minimum, especially in context with all the other privacy risks associated with having a smartphone that has always been able to track its users’ location with the apps that are already on most phones.

The Verge has an excellent article that answers the biggest questions about the technology.