COVID-19: Will a Contact Tracing App Help Ease Us Out of Lockdown?

Peter Russell

April 29, 2020

A contact tracing app designed to help the UK emerge from the COVID-19 lockdown will be ready by the middle of May, it has been confirmed.

That is also the target time set to recruit 18,000 coronavirus contact tracers, although Matt Hancock, England's Secretary of State for Health and Social Care was unable to update further on how much progress had been made.

At Tuesday's daily Downing Street briefing Mr Hancock would only say "we hope to have the contact tracers in place before, or at the same time as, the app goes live".

A Future Policy of Track and Trace

With no obvious end in sight to the current policy of social distancing to contain the pandemic, and the prospect of a vaccine somewhere over the horizon, the Government's strategy for easing restrictions centres around a track and trace approach to fight COVID-19, save lives, rescue the economy, and restore some semblance of normality.

The policy was set out last week in a letter from Richard Gleave, deputy chief executive of Public Health England, to directors of public health who he said would be "essential in taking forward contact tracing for this next phase".

The broad approach revolves around an automated system to detect who has been infected with SARS-CoV-2, identify who they have been in close proximity to, and trace those individuals.

At the heart of the 'track' element of the equation is the CV19 app, developed by NHSX, the digital arm of the health service.

On Monday, the BBC reported that the NHS had rejected a model proposed by Apple and Google in favour of its own design, which has undergone trials at RAF Leeming in North Yorkshire.

In common with the technology giants, CV19 uses Bluetooth low energy transmissions to log the distance between an individual's smartphone and other phones that have the app installed.

If a person becomes unwell, they can allow the app to inform the NHS which will assess symptoms for COVID-19 risk. If the disease is suspected, an alert will be relayed to other app users who had been in close contact with the individual over the previous few days.

Two Ways to Track: Centralised and Decentralised

The two models differ though in the approach they take. 

Apple and Google take a decentralised approach in which tracking and alerting take place between phones. The system will reply on coded 'handshakes' between devices, and alerts triggered from a database.

From May, both companies will launch application programming interfaces (APIs) to underpin apps from public health authorities that will be interoperable between IOS and Android systems. 

Privacy, transparency, and consent would be at the heart of their efforts, Google said in a blog earlier this month.

By contrast, the UK system would run via centralised servers, putting the NHS in control of who receives alerts.

Privacy Worries

That has triggered concerns about privacy and security.

Mathew Gould, chief executive of NHSX, and Dr Geraint Lewis, who is leading the programme, addressed these concerns in a blog post last week.

They stressed that the proximity log would be anonymous. "The data will only ever be used for NHS care, management, evaluation and research," they wrote. "You will always be able to delete the app and all associated data whenever you want."

Prof Eivor Oborn, a specialist in health technology at Warwick Business School, explained to the Science Media Centre: "I assume the Government want the data to study the COVID-19 pattern. For that they need all the data in their own server.

"However, no exit plan has been discussed for the app, which leaves concern about what they will do with data after the pandemic.

"The Apple approach involves less surveillance and is also more efficient on the battery. The UK app is trading efficiency and privacy for information and the potential to control the overall app tracking process, so they can easily update the code over time as the pandemic evolves."

The CV19 developers make it plain that future releases of the app could ask users for more information about themselves and places they have been to help the NHS identify hotspots and trends. Sharing the information would be voluntary but would "contribute towards protecting the health of others and getting the country back to normal in a controlled way, as restrictions ease".

International Examples

Different countries have adopted different approaches to the technology.

Under pressure over privacy concerns, the German Government has abandoned its own centralised technology approach in favour of the Apple-Google solution.

The Welt am Sonntag newspaper reported last weekend that Berlin now favoured a "decentralised software architecture" that would see data stored on users' phones instead of on a central database.

That was seen as jeopardising an initiative called Pan-European Privacy-Preserving Proximity Tracing (PEPP-PT), involving Germany's Fraunhofer HHI research institute and the Robert Koch Institute.

Other European countries are adopting the decentralised approach, such as the Swiss COVID-19 tracing app which uses Decentralised Privacy-Preserving Proximity Tracing Protocol (DP3T).

However, France – one of the hardest hit countries in the pandemic – has backed a centralised approach, with its privacy watchdog, CNIL, giving the go-ahead for a Government-backed scheme to monitor people infected.

It was reported last week that some functionality of the French system was being thwarted by Apple's security features, prompting Paris to ask the tech firm to turn off the feature in France that prevents data being moved from Apple devices via Bluetooth.

The Australian Government launched a tracking app on Sunday, COVIDSafe, which allows State and Territory health officials to contact users if they have been in close contact with someone who has tested positive for the virus.

The app was launched at 6pm local time and by 10.30pm had chalked up a million downloads and registrations, according to Greg Hunt, Australia's health minister. By Wednesday evening, Mr Hunt announced on Twitter that the app had "ticked past 3 million registrations", out of a population of around 25 million.

As with the French system, Australia's app is based on Singapore's TraceTogether software which was launched on the 20th March. Its designers at the country's Ministry of Health and GovTech say in the first month it achieved a 20% adoption rate with 1.1 million users, half of those coming in the first 24 hours.

What Will Happen in the UK?

The success of the UK's CV19 app will depend on how many downloads and registrations, and the proportion of the public who use it.

Asked how many that might involve, Mr Hancock could only say: "The more people who download the app and keep their Bluetooth on, the more effective the app is going to be. So, there is no answer, other than 'as many as possible'."

A study earlier this month by the  University of Oxford's Nuffield Department of Medicine said that the epidemic could be suppressed if 80% of all smartphone users used the app, or 56% of the population overall.

The researchers assumed overall smartphone use of 70% of the population, with low usage among the over 70s, the most vulnerable cohort in the population, and no app use in children under 10 years.

NHSX predicts that "millions of us are going to need to trust the app and follow the advice it provides".

According to Prof Oborn: "Given our near wartime conditions, many people might find the idea of voluntarily downloading an app preferable to remaining in lockdown, even if it constantly tracks you."


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