Georg installs the app on his mobile phone. If Georg becomes ill and his doctor tells him that he has COVID-19 disease, the app can identify other users of the app that he has been in close contact with before he became ill.
The phone's location service feature and Bluetooth detect nearby phones that also have the Smittestopp app. Anyone who is defined as being in close contact with Georg over the past few days will receive an SMS notification with advice on what they should do. They are not told that Georg is infected.
When Georg tested positive, the manual contact tracing began. The healthcare service in Georg's municipality will try to identify who he has had contact with during the last fortnight before he became ill, and will interview him about this. Georg tries hard to remember, but unfortunately cannot be sure that he remembers everyone. Therefore, not all of the people he has been in close contact with are noted in the interviews. However, if both Georg and the close contacts use the Smittestopp app, the close contacts will receive a text message.