NHS Covid-19 app: How England and Wales’ contact-tracing service works

NHS Covid-19 app: How England and Wales’ contact-tracing service works

By Leo Kelion and Rory Cellan-Jones
Technology reporter

NHS Covid-19 App

It’s been a long time, but England and Wales’s Covid-19 app will launch on Thursday.

It follows in the footsteps of Scotland and Northern Ireland’s efforts, but has more features.

Apple and Google’s automatic contact-tracking technology will be used to tell people to isolate themselves if their phone detects that they were close to someone who was later determined to have the virus.

But there’s more, including:

  • a barcode scanner for check-in
  • a control of the level of risk based on the postal code
  • a symptom reporter tool
  • the means to order a coronavirus test and receive the results
  • a countdown to keep track of how long to stay in self-isolation
  • a guide to the latest advice on local restrictions, financial support and other related information

copyright of the imageDepartment of Health

image captionThe app keeps track of where the user has been to alert them if one is subsequently linked to an outbreak

So while contact tracing may seem like the main feature, health leaders say the main goal is to change people’s behavior to make them less likely to catch or pass on the coronavirus.

How can people access the app?

The app is only available for smartphones, not for tablets, smartwatches or other devices.

To get started, go to Android’s Google Play or Apple’s App Store and search for “NHS Covid-19”.

Phones must have Android 6.0 (released in 2015) or iOS 13.5 (released in May 2020) and Bluetooth 4.0 or later.

image captionThe app first asks the user for permission to use Bluetooth and their postcode, before revealing their splash screen

And some of the latest Huawei phones are excluded.

How will it send contact tracking alerts?

When two devices running the app are close together, they exchange Bluetooth “handshakes” to determine distance and duration, measured in five-minute sessions.

The measurements aren’t always accurate and work continues to improve them, but the logs are used to create a cumulative score for the set of interactions between two people over the course of a day.

If the points threshold is reached and one owner subsequently shares a positive coronavirus test via the app, the other will receive an alert.

What will this notice say?

The notification will tell the recipient to self-isolate for two weeks and trigger the app’s countdown to start.

But the recipient is not told who triggered the alarm.

And authorities can’t identify any of the parties, although they can keep track of how many people have been told to self-isolate.

Even if the recipient has no symptoms or a subsequent negative test result, they must stay home for the duration.

Can users be fined if they ignore a self-isolation warning?

From 28 September,

people in England can be fined £ 1,000 or more for violating self-isolation rules.

But because the app allows users to remain anonymous and the health chiefs want it to be popular, fines for users shouldn’t be an issue.

Unlike when a human contact tracker orders someone to isolate themselves, the app keeps the subject’s identity secret.

Only if they contact them later, for example to arrange a financial support payment, will their name be registered.

How will the venue check-in process work?

Restaurants, bars and other leisure facilities should display an authorized QR barcode on a poster or digital sign, which the app can scan.

image captionThe app only recognizes QR codes related to the check-in scheme, to which activities must be registered

The venue will then be added to the app’s “digital diary” with the places visited by the user.

And the user will not have to provide their name and address to the venue.

If officials later believe the place is the center of an outbreak, they can trigger an alert for users who were present.

And this notification could tell them to use the app’s symptom checker and / or self-isolate.

How will the postcode function work?

When a smartphone owner uses the app for the first time, they are offered the option to type the first part of the postcode, for example “M23”.

Typically, thousands of other families will have the same code, so while this involves sharing information with authorities, it shouldn’t identify people.

image captionThe app can trigger notification alerts to alert the user if the local risk level has changed or if they have been linked to someone who has the coronavirus

The user is then assigned a risk level for their neighborhood, at the top of the app home screen, and can receive an alert if it changes.

And in turn, the NHS and local government can collect data on the number of app downloads and coronavirus cases in their area, helping them manage the crisis.

How will the app order a test?

Users can report symptoms – and when they started – at any time.

If they suggest an infection, the user is told to book a test and that all family members must isolate themselves for eight days.

Booking a test involves using an external website, which requires the user’s name and address.

But these personal details are not shared with the app.

And a unique code allows users to receive the test result via the app as soon as it’s ready.

Will the app drain the battery and allowed data?

The developers suggest the app should account for less than 5% of a device’s battery usage.

But if the phone is set to use a low-power mode, owners would need to go into settings to exclude the app so it can continue to track contacts at all times.

And while the app continually checks for updated data, it shouldn’t have a significant impact on people’s benefits.

What if users travel to Scotland or Northern Ireland, which have their own apps?

The framework from Apple and Google will not allow two apps to contact the track at the same time.

Therefore, when users cross the border, they need to open the local app and enable contact tracking within it.

A message will appear asking, “Change exposure notification app?”

image captionGoogle Play shows users which UK related contact tracking apps are available to them

This will disable the one they were using previously.

What happens if users work with DPI or behind a perspex screen?

While users are normally encouraged to keep the app active and their phone close at hand whenever they are away from home, there are exceptions.

To prevent people from being told to isolate themselves when they have been protected, or for phones to register each other while in lockers, there is an option to temporarily disable contact tracking at the bottom of the main screen .

How will the app connect with other endeavors?

Although human and automated contact tracing systems are deliberately kept separate, they should complement each other.

So, for example, if you were in a queue at the grocery store, human tracers might have a hard time identifying the next person in line, but the app would be able to.

Likewise, if you were in a pub where an infectious user was sitting but not using the app, you may still receive an alert via the check-in service.

Will it make any difference?

According to models made by the University of Oxford, the app can significantly reduce deaths and hospital admissions if at least 15% of the population uses it.

But real-world data on the effectiveness of such apps in other countries using them is scarce.

And so far, they’ve been offered when infection levels were relatively low, meaning the chance of a user getting an alert has been slim.

Most people have yet to be convinced to install them: around a third of the population in Ireland, 22% in Germany and only around 4% in France have done so.

With the resumption of Covid-19, things could change.

And as health managers note, there are other measures of success, including whether those who download the app open it regularly and then change their behavior accordingly.

Related topics

  • Contact tracking

  • Test for coronavirus
  • App

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