What is it and how does it work?
A contact-tracing app is designed to let people know if they have been in close contact with someone who later reports positive for Covid-19.
It could pinpoint exactly who needs to be in quarantine and who doesn’t, making it key to easing up social distancing measures. The purpose of the contact-tracing app is to try and track down people and alert them of the need to self-isolate faster than traditional methods. Users who download the app to their phone can voluntarily opt-in to record details of their symptoms when they start to feel unwell.
The app keeps a trace of others who have been in close contact through Bluetooth signals that transmit an anonymous ID. These low energy Bluetooth signals perform a digital "handshake" when two users come into close contact, but keep that data anonymous. If an individual later reports that they are positive for coronavirus, it will then ping a message to people who have been in close-contact with them in the last 28 days based on their anonymous IDs.
The app will recommend those people self-isolate in case they have contracted the disease. Those contacted won't know the identity of the person who may have passed on coronavirus. If the person then takes a test and tests negative, they may be released from their self-isolation by a notification through the app.
The NHS's technology and research arm NHSX has developed the app with researchers from Oxford University and using developers from tech companies like VMWare. It has also been in contact with Apple and Google, although it is using different technology to those technology companies and has rejected their approach.
The technology the NHS has built will allow smartphones to track every other device they have come into contact within the 28 days using Bluetooth signals. Records of contacts will be stored on phones. If a user comes down with coronavirus symptoms they report this in the app. That data is then shared with a health service database and their anonymous ID matched with other phones they have come into contact with.