SwissCovid – a tracing app developed in part by EPFL – is being made available today to the general public, one month after the pilot tests began. The app will be a useful tool in stemming the spread of the disease as the number of cases in Switzerland is back on the rise.
The World Health Organization was clear in its warning: the COVID-19 pandemic is not over, and in some places it’s just as strong as ever. Many countries, including Switzerland, have managed to keep the virus’ spread under control, but the emergence of new hotspots shows that it’s too soon to let our guard down. Hygiene measures and other recommendations can still slow transmission chains. Now Swiss public health officials have a new weapon to combat SARS-CoV-2: the SwissCovid tracing app. Developed over the past few months by an international team, it will be released to the general public at midnight on 25 June 2020. Alain Berset, head of the Swiss Federal Department of Home Affairs, stressed at a press conference today that it’s essential for as many people as possible to download the app so that the cantonal doctors don’t rely on manual tracing alone to identify those who have come into contact with a carrier of the new coronavirus.
The cantonal doctors conduct a form of manual tracing whereby people who may be infected are notified and instructed to take the appropriate measures (self-isolation and mask-wearing, for example). Scientists estimate that someone infected with the new coronavirus is contagious up to 48 hours before the first symptoms appear. Manual tracing therefore aims to identify everyone who was in contact with a COVID-19 patient during the two days before he or she started showing symptoms.
Although this method is fairly effective, it has some drawbacks. It’s not easy to remember every person you came into contact with over a given period – and if you used public transportation or went to a restaurant, for instance, you probably came into contact with people you don’t know.
That’s where the SwissCovid app comes in. It automatically sends alerts to everyone who was within 1.5 meters of a COVID-19 patient for over 15 minutes (the exposure that scientists believe is necessary to become infected) – provided that the patient and the people around him or her have the app. Once a patient tests positive for the disease, he or she must enter his “Covid code” in the app; the notification sent to other users is anonymous.
Data security a top priority
The app uses the DP3T protocol, which was developed by a consortium of researchers led by EPFL and ETH Zurich. It is designed for use with both the Android and iOS (Apple) operating systems, making it compatible with almost all smartphones currently on the market. Because the data are stored on users’ phones rather than a central server, they are extremely difficult to hack. And they are stored in a way that makes it impossible to automatically identify users who send out a Covid notification. A data risk assessment