Almost one-third of people who should be alerted by someone else’s positive coronavirus test through the new NHS Test and Trace app will not receive a notification.
The new app is being trialled in the Isle of Wight and Newham, East London, after the original one was scrapped during the testing phase.
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The app will log the time and distance a user of the app has spent near to other users through bluetooth mobile technology.
Anyone who tests positive to the virus must then log this in the app.
App users who have been in close contact with the positive case will then be told to get tested or self-isolate.
However, the app’s so-called true positive rate is just 69 per cent.
This means that 31 per cent of people who have been in close contact with a coronavirus case registered on the app will not be alerted.
This could mean that many people slip through the cracks and could potentially spread the virus.
However, NHS Test and Trace chief executive Dido Harding said the app was meant to be used alongside the already operational manual Test and Trace system, and not as a standalone measure.
“By launching an app that supports our integrated, localised approach to NHS Test and Trace, anyone with a smartphone will be able to find out if they are at risk of having caught the virus, quickly and easily order a test, and access the right guidance and advice,” she said.
“The app is a great step forward and will complement all of the work we are doing with local areas across the country to reach more people in their communities and work towards our vision of helping more people get back to the most normal life possible at the lowest risk.”
The new app will also have several other features, such as alerting people to Covid rates in their postcode and an option to check-in to venues through scanning a QR code.
It will also help people to book a test if necessary.
People on the Isle of Wight, along with NHS staff, can start to use the new app today, with the Newham trial launching in the coming weeks.
A Department of Health spokesperson said: “We have worked with Google, Apple and the Alan Turing Institute to optimise the app, it operates in the same way as all other similar apps around the world and the level of accuracy is deemed to be as precise as human contact tracing.
“The app tells you about positive cases that you may not have not known about otherwise and complements the national NHS Test and Trace system.”