Proposal for a location-based COVID-19 contact tracing app: Contacts of individual A (and all users of the app) are traced using GPS co-localisations with other app users, supplemented by scanning QR codes in high-traffic areas where GPS is too coarse. Individual A requests a SARS-COV-2 test (using the app) and their positive test result triggers instant notification to users who have been in close contact. The app advises isolation for the case (individual A) and quarantine of their contacts.[1]
Digital contact tracing is a method of contact tracing relying on tracking systems, most often based on mobile devices, to determine contact between an infected patient and a user.[2] It came to public prominence in the form of COVID-19 apps during the COVID-19 pandemic.[3][4][5] Since the initial outbreak, many groups have developed nonstandard protocols designed to allow for wide-scale digital contact tracing, most notably BlueTrace and Exposure Notification.[6][7]
When considering the limitations of mobile devices, there are two competing ways to trace proximity: GPS and Bluetooth; each with their own drawbacks. Additionally, the protocols can either be centralized or decentralized, meaning contact history can either be processed by a central health authority, or by individual clients in the network. On 10 April 2020, Google and Apple jointly announced that they would integrate functionality to support such Bluetooth-based apps directly into their Android and iOSoperating systems.[8]