The NHS Contact Tracing App: What? Why? When? And; How will my data be used?

Following on from our previous article detailing the technologies being used in the fight against COVID-19, and the privacy implications of a contact tracing applications, this article aims to provide you with more details on the controversial UK COVID-19 tracking app.

03 June 2020

Closeup shot of modern smartphone with GPS application showing map of city

By Eloise Bevan, Innovation Funding Consultant at ABGI-UK


The ‘NHSX’ has been established as a technology and research arm of the NHS, and it is this division which is working with researchers at Oxford university and Tech company VMWare to develop a centralised COVID-19 tracking app for smartphone users. As of the 5th of May 2020, the tracking app was released for trial by local government and health-care workers on the Isle of Wight. On the 7th of May, all 142,000 inhabitants of the Isle of Wight will be able to download the app and, if successful, given access to the wider UK population within weeks. However, fast forward two weeks to the 21st of May, and headlines are expressing doubts on whether the NHSX’s app will be ready for launch on June 1st. In addition, when the app is launched in the UK, it remains uncertain whether this will be the centralised tracking app developed and operated by the NHSX, or if we will be using the alternative decentralised tracking app currently being developed in collaboration by tech giants Apple and Google.


The first thing you see on the NHSX webpage for the COVID-19 tracking app, is the following statement: ‘Technology has the potential to save lives and help the country deal with the COVID-19 pandemic.’ The truth of this statement has been demonstrated by other countries who have successfully used tracking app technology to fight the pandemic. South Korea, for example, whose previous experience with a virus lead to the swift deployment of their tracking app in the early stages of the COVID-19 outbreak. The fast deployment lead to a timely demise of Wave 1, with a low mortality rate. With the UK becoming the worst hit country in Europe, in excess of 37,000 deaths at the time of writing, and as the economy takes a huge hit as a consequence of the lockdown, it comes as no surprise that Britain is keen to implement a similar technology-based strategy. Not only to keep the population safe by minimising transmission, but to allow people, businesses and international relations to return to some form of normality.


It is now June 1st and we still have no nationwide tracking app! So, when will we get one? And, will it be centralised (NHSX) or decentralised (AppleXGoogle)? Well, we can’t say for certain yet, but as with any technological developments, it is unrealistic to think that this will just happen overnight. Not to mention the intended scale of the app: when it does launch, the hopes are for to the app to be downloaded and used by over 60% of the population (in order to be successful). It is therefore no surprise that some delays in development are currently being experienced, in order to ensure its ultimate success.


So, how will my data be used on the centralised NHSX COVID-19 tracking app, and what about the decentralised app?

For the NHSX centralised app, the collection and use of a user’s data is by consent only and, following concerns raised about the use of GPS contact tracing, the app will instead use Bluetooth signals. When two people meet, their phones will exchange a unique ‘key/ID’ to identify each phone. If you test positive for COVID-19, the previous 14 days of Bluetooth ‘keys’ are uploaded, and the central database will use an NHS clinical algorithm will identify the risk posed by each interaction (based on duration and proximity). If an interaction is determined to be a ‘risky contact’ the other person will be notified to isolate. The app keeps users’ identities anonymous and additional measures are also in place to ensure that no data is stored for longer than 28 days.

A decentralised tracking app also shares unique key/ID between phones. However, the ‘risky contact’ made between users is determined by the user’s phone, which regularly downloads the up-to-date version of the database to scan for interactions, as opposed to storing and analysing the interactions through the central database. The user’s app will then notify them if they have been in contact with an infected user.

With the government reassuring the public that the tracing apps had been designed with privacy at "front of mind", we can conclude that both apps present a very viable and modern technological method to track the spread of a virus, reduce its transmission and allow the population and economy to progress safely out of lockdown.

Figure 1 – Centralised Vs. Decentralised