NHS contact tracing app: how does it work and when can you download it? 

With Britain in lockdown, the Government has been racing to find ways to ease restrictions without putting public safety at risk.  

One solution is a contact-tracing app that can enable digital contact-tracing on a large scale.

On May 4, the government revealed further details of the app, which will be tested on the Isle of Wight and then launched to the rest of the UK by the end of the month, if it proves successful. The app went live on the island on May 5.

The UK is planning to use trained teams to find people who have coronavirus symptoms, working with the Army to make thousands of calls a day to track the spread of Covid-19, all of which will be complemented by the contact-tracing app.

But Matt Hancock, the Health Secretary, has faced criticism for so far recruiting only 1,500 contact tracers of the Government’s 18,000 target by mid-May.

And contact tracers are only being hired by the Government for an initial three months – – seemingly running contrary to the advice of health experts, who predict the staff will be needed for up to 18 months to assist in controlling the spread of the virus.

But what exactly is contract tracing, can it really help lift the lockdown measures, and when will it be available? 

What is it and how does it work?

A contact-tracing app is designed to let people know if they have been in close contact with someone who later reports positive for Covid-19.

It could pinpoint exactly who needs to be in quarantine and who doesn’t, making it key to easing up social distancing measures. The purpose of the contact-tracing app is to try and track down people and alert them of the need to self-isolate faster than traditional methods.

Users who download the app to their phone can voluntarily opt-in to record details of their symptoms when they start to feel unwell. 

The app keeps a trace of others who have been in close contact through Bluetooth signals that transmit an anonymous ID. These low energy Bluetooth signals perform a digital “handshake” when two users come into close contact, but keep that data anonymous. 

If an individual later reports that they are positive for coronavirus, it will then ping a message to people who have been in close-contact with them in the last 28 days based on their anonymous IDs. 

The app will recommend those people self-isolate in case they have contracted the disease. Those contacted won’t know the identity of the person who may have passed on coronavirus.

If the person then takes a test and tests negative, they may be released from their self-isolation by a notification through the app.

For trials on the Isle of Wight, people who voluntarily report their symptoms will be brought a testing kit within 24 hours, the government has said.

The data will not be stored longer than 28 days and the NHSX has said it will be deleted after the app’s use is finished and the pandemic is over.

What is the technology behind it?

The NHS’s technology and research arm NHSX has developed the app with researchers from Oxford University and using developers from tech companies like VMWare. 

It has also been in contact with Apple and Google, although it is using different technology to those technology companies and has rejected their approach.

The technology the NHS has built will allow smartphones to track every other device they have come into contact with in the 28 days using Bluetooth signals.

Records of contacts will be stored on phones. If a user comes down with coronavirus symptoms they report this in the app. That data is then shared with a health service database and their anonymous ID matched with other phones they have come into contact with. 

People who they have been in close contact with will then be sent a notification urging them to isolate.

This data will not be linked to people’s names but use anonymous IDs linked to a device, so phone owners will not know who might have passed on the virus. They will, however, be asked to share the first digits of their post code.

When will it launch? 

The app is currently not available widely, but launched on the Isle of Wight on May 5. NHSX chief executive Matthew Gould said the app will be two to three weeks away for the rest of the country.

Matthew Hancock, the health secretary, said that people on the Isle of Wight would be written to with details on how to down load the app from the government. He said the slogan for the NHS would be: “Stay at home, install the app,  protect the NHS, and save lives.”

Will the app track GPS or need mobile data?

The NHS app uses Bluetooth signals to check for contacts. This means it does not need to connect to mobile data when you are out and about. For now the app does not track GPS signals.

The NHS said it might introduce a system of monitoring location data in future to collect useful data on the pandemic, but that would be voluntary.

Are there privacy concerns?

Some privacy experts have raised concerns that patient confidentiality risks being compromised.

Dr Yves-Alexandre de Montjoye, head of the Computational Privacy Group at Imperial College London, has warned that such apps could “collect sensitive information like location data”. 

“We need to do everything we can to help slow the outbreak. Contact tracing requires handling very sensitive data at scale, and solid and proven techniques exist to help us do it while protecting our fundamental right to privacy. We cannot afford to not use them,” he said. 

Mr Hancock has pushed back against the privacy concerns, claiming that data would only be held as long as it was needed and that “all data will be handled according to the highest ethical and security standards”.

“If you become unwell you can securely tell this new NHS app, and the app will then send an alert anonymously to other app users who you’ve been in significant contact with,” the health secretary said. 

Have other countries made something similar?

In Singapore, a contact-tracing app called TraceTogether has been rolled out by the government to track those who might be infected by coronavirus.

Since March 20 it has been downloaded over 800,000 times in the hopes of creating a “community-driven” response to the virus. 

What are Apple and Google doing?

The two tech giants have teamed up to offer each country a piece of technology that will help turn all iPhones and all Android phones (apart from newer Huawei devices) into contact tracing devices.

Apps that use the API (which must be made by a public official) send users “exposure notifications” if they have been in contact with someone who contracted coronavirus. 

The system records contact as when a smartphone is within a couple of feet of another device for up to 10 minutes. Bluetooth wireless technology can sense devices from up to 15 ft away.

Even if people from different countries or states have different contact tracing apps, the system is interoperable and will be able to alert them to exposure. Authorities that want to collect location data of people will not be allowed to use the technology, but are open to building their own. 

In coming months, they will integrate the technology directly into their operating systems to reach more people. Their tools will be “decentralised” and not send data to central health authorities, but will instead pass it from phone to phone.

Google said that the tools would be added to Android via a download in the Google Play store. Apple will offer it via an iOS software update. Apple said the goal is to make it compatible with as many iPhones as possible, including older models.

The functionality will only be available to public health apps so outsider developers won’t be able to use that data. It also means that users will have to download an official app to input test results.