The U.K. wanted to make an app to trace coronavirus infections and had been testing on out on the Isle of Wight this spring. But going on its own, the government admitted that it would take way too long to publish and opted instead to adopt tracking APIs created jointly by Apple and Google. Now, the rewound NHS COVID-19 app is out for trials.

The app was released to the Play Store on August 10. Isle of Wight residents are being mailed join codes to enter the app while NHS volunteer responders across the nation are also being given access. The London borough of Newham will be brought in later on for a 3-week run.

With the app, users will be able to check their area's risk assessment, verify and report their symptoms, book a test, and, if need be, track their self-isolation countdown.

The actual, passive tracking relies on Apple and Google's APIs which anonymously ping other devices that use the NHS COVID-19 app through Bluetooth Low Energy how close and for how long people are near each other — you can read our write-up about how the technology works here. In addition to passive tracking, users can also check into venues like restaurants, religious centers, and other such places that will provide a special QR code to scan in the app.

When someone reports a positive test, users that have been in close contact with them will receive an alert and advice on what to do next. Risk is algorithmically calculated where "close contact" and, therefore, an increased risk of contracting coronavirus occurs when a person is within 2 meters of a carrier for 15 minutes or more.

It's hoped that the app will bolster the U.K.'s Test and Trace campaign that will keep those who come under COVID-19 away from others faster and lessen the crush on hospitals.