The NHS COVID-19 app is no longer in use and the Isle of Wight trial has now ended. This is archived information from 18 June 2020. If you still have the app, please uninstall it.
The NHS COVID-19 app uses Bluetooth to record the distance over time between people who have downloaded the app. If a person reports coronavirus symptoms, their recent history of interactions is used by the algorithm to update the risk-score for every app user they have come into contact with.We have published the Risk-scoring Algorithm (Interim): Technical Information (PDF:133KB) that summarises how the NHS COVID-19 app will initially calculate a risk-score for an individual based on their recent contact with people who report that they have coronavirus symptoms.