On 13 May 2020, Switzerland’s government published more information on the Swiss Proximity Tracing App (Swiss PT), an app designed to slow the spread of SARS-CoV-2.
Developed by teams at EPFL and ETHZ, the app uses Bluetooth to detect when your phone comes within two metres of another phone or device with the app. It then records the contact as an anonymous key and the duration of contact, flagging any close contact longer than 15 minutes. All data is encrypted and deleted after 21 days and is automatically removed from the device when the app is removed, according to the government.
The app is free and downloading it is voluntary. It will work on any device with iOS (13 or later) or Android (6 or later), a Bluetooth connection and at least 10Mo of space.
If someone with the app tests positive for SARS-CoV-2, they will be given a code, which they can voluntarily enter. Once entered, those with the app who have spent at least 15 minutes in close contact (2 metres or less) with the infected person will be notified via the app. The notification keys required for this process will reside on a federal government server located in Switzerland.
The technology has limitations. Unlike the virus, Bluetooth can pass through physical objects, so some close contact could be spread free if there is a window or wall separating people. It also records phone proximity, not human proximity, and, like social distancing, it will only work if enough people use it. Various studies suggest a majority of human contact would need to be traced to make it effective.
The aim of the technology is to alert those who might have been infected. This will help people with potentially mild symptoms to notice them and help them to decide to self isolate to reduce viral spread and protect anyone with underlying health conditions.
According the the Swiss government, conditions that increase the risk of death from Covid-19 include cancer, cardiovascular disease, chronic respiratory diseases, conditions and therapies that weaken the immune system, diabetes, high blood pressure and obesity – a more detailed list of conditions is listed here.
Switzerland’s federal council plans to discuss the formulation of a new law to permit the use of the app on 20 May 2020. This would then be presented to parliament in June 2020 for parliamentary discussion and approval.