Why we need the Corona App

Michael Hengartner is President of the ETH Board - and thus something like the chief researcher of Switzerland. In his column he explains interesting facts from the world of science. This week he explains why he is going to install the corona app.
Testing the DP3T app with the help of a 100 Swiss soldiers

Imagine the following story: tomorrow, you and I happen to be sitting across from each other on the train. Most likely we talk! About how we like life to get a little more normal again.

Then something stupid happens: After our train ride I get a fever and start coughing – coronavirus. Now it would be good if I could warn you – after all we had such a good time! Warn you that I might have infected you. That you should let yourself get tested. That you may be unwittingly infecting your family and friends. Too bad that I don’t know your name or how I can reach you.

This train story is a typical Corona story: It often takes a long time until you realize that you are infected. Unsuspectingly, you infect people who, also unsuspectingly, spread the virus. It would now be important to warn these unsuspecting people quickly. But how?

«Personally, I find their Swiss Contact Tracing App very promising – precisely because it does not do a lot of things!»      Michael Hengartner

A discreet tracing app

Professor Carmela Troncoso and her colleagues from EPFL and ETH Zurich have the answer. They have developed an app that can be used to follow up who met whom and perhaps infected whom, and this without any loss of privacy.

Honestly, it’s one of those things with these apps: many people know far too much. Google, Facebook, WhatsApp or Instagram know where we live, who our friends are or what we do on the Internet. Nobody in Switzerland would want a Corona app that monitors us at every turn.

That's why privacy protection is a top priority for Troncoso and her team. Personally, I find their Swiss Contact Tracing App very promising – precisely because it does not do a lot of things!

For example, there is no tracking. The app doesn't use GPS, it just uses Bluetooth to search for other mobile phones that are nearby (up to a few meters away) and have the app on their mobile. So, if we both sit opposite each other in the train, the apps on our two phones know that they have, let's say, come quite close for a long time.

But they do not know where that was. They also don't know the name of the person opposite. The proximity data always remains on our own mobile phones. The program is open source: So IT cracks can see without difficulty exactly how the app works. And 14 days after our train ride, the app forgets that we ever met. Because if neither you nor I have fallen ill by then, it means that our encounter hasn’t harmed our health.

A message from the FSO

But in case I should test positive for Corona – as in the story – I receive a code from the Federal Statistical Office and can then sound the alarm via the app. You will receive a message telling you that you may be infected. So, you can get tested. And stay away from high-risk patients until you know if you're contagious.

The app will soon be available for both iPhone and Android phones. I will definitely install it.

The article originally appeared in SonntagsBlick.