On 25 June 2020, Switzerland’s contact tracing app, known as SwissCovid, became available for download.
Created by a group of specialists at EPFL led by Marcel Salathé, a professor of digital epidemiology, the app allows chains of infection to be traced by informing people if they have been in contact with anyone infected. Countries, like South Korea, that have done a good job of this have been able to quickly isolate infected people and halt the spread of the virus. The per capita rate of infection in South Korea stood at 245 per million on 25 June 2020. The same figure for Switzerland was 3,626 per million.
The SwissCovid app, which can be downloaded from the relevant phone app store, is issued by Switzerland’s federal government. The app is able to notify and receive notification from people that you don’t know personally and aims to do a better job of breaking chains of infection.
The app uses bluetooth to sense other phones in close proximity. If someone you have been in close contact with later tests positive for SARS-CoV-2 you will be notified, enabling you to test and isolate before you have a chance to infect someone else.
If someone using the app tests positive, they can request a code, known as a Covidcode. Upon entry, data from the infected person’s phone is shared with a central server, which then sends messages to all those using the app that were in close contact with the person. These people can then test and isolate. The video below shows how it works.
For the app to work bluetooth must remain on, elevating energy use slightly.
Using the free app is voluntary. To make the system effective, some argue that 60% of the population would need to use it. However, others disagree. Modelling done at Oxford University suggests that the effectiveness of tracing apps isn’t binary. Their model shows that even 10% app penetration would have an impact. However, the relationship between download rates and impact is not linear. If the app is running on 56% of phones the impact could be seven times greater than if it is on 28% of phones.
According to a recent survey, willingness to use the app across Switzerland fell from 65% to 54% between April and June 2020.