NHS COVID-19 app: preventing 600,000 cases of COVID-19

NHS Test and Trace (NHSTT) is a central part of the government’s COVID-19 recovery strategy. Testing to identify cases and tracing those who may have contracted COVID-19 through social contact is essential to control the spread of the virus. The NHS COVID-19 app complements NHS Test and Trace processes by extending the speed, reach and precision of contact tracing. It allows close contacts unknown to the individual who has tested positive, for example strangers on public transport, to be notified to self isolate, if they are also an app user.

The NHS COVID-19 app is the first app in the world to use the latest Google Apple technology to better gauge distance to identify those most at risk. If a user tests positive for COVID-19, they can choose to anonymously share their result with their close contacts via the app. The app is designed so that the data tracks the virus, not the people, utilising the latest in data security technology which protects privacy while notifying users when they are at risk. The data acquired by the app is helping to build our understanding of how many people have potentially been exposed, how many times symptoms have been reported, and how often test results are positive or negative. It also demonstrates the app’s efficacy. From September to December 2020, it had shown that approximately 600,000 cases of COVID-19 had been prevented as a result.

Professor Mark Brier, Lead Scientist for NHS COVID-19 app

"It's widely acknowledged that the NHS COVID-19 app is an important tool in our pandemic response. We know that the more people who download it, the better it works.

"I was delighted to learn that the app has now been downloaded 21.8 million times. This represents 56% of the eligible population aged 16+ with a smartphone and it was the UK’s second most downloaded free iPhone app in 2020. Not bad for an app that was developed in just 12 weeks. More importantly for me and my colleagues, it’s good to know the NHS COVID-19 app has been breaking chains of transmission to protect users and the communities in which they live since its launch in September. So far our analysis has found that over 1.7 million app users across England and Wales have been advised to isolate via the app following close contact with someone who’s tested positive. Our statistical analysis showed that approximately 600,000 cases were prevented as a result, which is staggering.

"The app is the fastest way to notify people who’ve been put at risk of contracting the virus. As you may already know it sends alerts to people who’ve had close contact with someone with the virus as quickly as 15 minutes after an app user enters a positive result into the app. Isolating when receiving a notification has and continues to prevent the spread of the virus.

"I’d also like to reassure users and those who are thinking of downloading it that the data we gather is securely held. In fact, it was designed with privacy in mind. The app tracks the virus not people, utilising the latest in data security technology to protect privacy while notifying users when they are at risk. We don’t ask users to input any personal information which could identify them, we just ask for the first four digits of their postcode.

"Naturally, the impact of the app can be increased by more people using it: If there was an increase of 1% of the population using the app, my team and I are confident cases can be driven down by approximately 2.3%. The epidemiological outlook remains concerning, however, I believe the app is a vital tool in curtailing the spread of the virus, especially as we emerge from lockdown. Using the app can contribute to reducing infections until we are all vaccinated. At a time of great need, our ability to gather, analyse and share data has been critical for the COVID-19 response and long may it continue. During the pandemic we’ve progressed at such a pace that it’s unimaginable not to make this the new way of working."