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Laurie Clarke


How will the NHS Covid-19 contact tracing app work and when will it go live?

This article is regularly updated to reflect emerging developments. 

After a short hiatus,  the UK has announced that its coronavirus contact-tracing app is back on track. A trial of the new app kicked off on August 13 that includes residents in the Isle of Wight, the London Borough of Newham and NHS volunteer responders first.

The app integrates the Apple-Google bluetooth tracking framework and will notify you of the need to self-isolate if you have been in prolonged proximity to someone that later reports being infected with Covid-19.

In addition to this, the app will alert users about the level of local risk in their area (based on the first three letters of their postcode), a QR barcode scanner where users can check into a venue and later be notified if others there tested positive, a symptom checking tool that lets users book a free test and receive the results via the app, and a countdown tool that tracks how much longer you need to self-isolate.

The technology is still some way off perfect. The false positive rate (where users are incorrectly flagged despite being more than two metres apart) currently stands at 45 per cent. On the other hand, 31 per cent of cases are missed when the handsets were within range. However, if the range is extended up to five metres, phones are correctly determined to having been in range in more than 99 per cent of cases.

Speaking about the new app, executive chair of the NHS Test and Trace programme Dido Harding said: “It’s really important that we make it as easy as possible for everyone to engage with NHS Test and Trace. 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.”

There is currently no official date for the new app to be rolled out nation-wide.

The new release of the current app has followed a long and arduous process. Back in May, the NHS announced the imminent launch of a coronavirus tracking app that would let users know if they’ve been in close proximity to someone infected with coronavirus and need to self-isolate. 

However, a series of missteps led to the app in its first iteration being dropped and the government saying it would pivot to the model being developed by Google and Apple instead on June 18.

Read next: Where did it all go wrong for the UK’s Covid-19 contact tracing app?

The original app was piloted on the Isle of Wight, where it became clear that technical issues with the centralised app design meant that it wasn’t functioning properly on iPhones.

The app was initially considered to be one of the central planks of the government’s strategy for how the UK could gradually lift lockdown conditions, but is now considered to be an add-on to the wider Test and Trace programme. 

How will the contact tracing app work?

The app will log, using Bluetooth LE (a standard feature that runs continuously and automatically on your smartphone), the proximity of other people who have the app installed. A record of this “anonymous proximity information” will be stored on the device. Users will be encouraged to enter into the app whether they have experienced symptoms of coronavirus. If a user reports symptoms of Covid-19, all of their contact data for the previous 28 days will be uploaded to the central server. All of the people they came into close contact with will then receive an alerts of the need to self-isolate.

When will it launch?

The app is currently undergoing a trial but there is no firm launch date for the app as of yet.

Will it be voluntary?

The app will be voluntary to download. However, according to researchers, it will only be effective at tracking and curbing the spread of coronavirus if at least 56 to 60 per cent of the population download it. The adoption rates of other nations’ coronavirus tracking apps are not particularly hopeful. Only one in six people signed up for Singapore’s voluntary TraceTogether app. 

Will it infringe on my privacy?

When the government planned to launch a centralised app, there was concern over whether users’ data would be safe. A number of privacy experts highlighted a range of problems associated with the planned design, including that the data can be used to build a social graph of an individual’s contacts, that this type of app is vulnerable to mission creep, and that individual’s could theoretically be subject to persistent tracking using the app. 

Wariness around that app was fuelled by a report from the Guardian revealing that a draft government memo explaining how the NHS contact tracing app could work noted that ministers might be given the ability to order “de-anonymisation” at some point to identify people from their smartphones. It said the app could use device IDs, which are unique to all smartphones, to reveal users’ identities, if deemed “proportionate at some stage”. It didn’t detail under what circumstances such a measure would be ‘proportionate’. A spokesperson from NHSX denied that this had ever been on the table. 

However, the Apple and Google framework is decentralised, meaning data is stored on the phone instead of being sent to a central database. This, privacy advocates argue, means that this model is far less intrusive and prone to being exploited.