The new NHS contact tracing app: Everything you need to know

The new NHS contact tracing app: Everything you need to know

The app that was behind the NHS Test and Trace project did not work. On September 24, a second NHS Covid-19 app went live. Here’s how it works



Track, trace and test. Since the first peak, England has been using this mantra to fight coronavirus. However, things have not always gone according to plan.

Coronavirus cases have risen in autumn and the testing system has been disrupted..

After months of delays, England finally has a Bluetooth-based app for contact tracing. It will alert people when someone has been close to someone with coronavirus. People can also check their symptoms and book tests.

After being tested in Newham, London, and on the Isle of Wight, the contact tracing app will launch in England and Wales in September 24. Scotland and Northern Ireland have previously launched their own contact-tracing apps.

How to download the NHS Contact Tracing App

Download the NHS Covid-19 contact trace app for England and Wales for Android and iPhone now It is available for free from Google Play or the App Shop. How does the app work? What data does it collect? This comprehensive guide will tell you everything.

What is contact tracing? How does it work?

Contact tracing, a proven method to control the spread of diseases, is well-known. It’s commonly used for sexually transmitted infections, , including HIV. To build a picture of other people who might have been exposed, the infected person must recount their movements and activities.


Covid-19 is very sensitive to this. This is crucial with Covid-19. The virus can be very contagious. Symptoms may take up to a few days before they appear. People might also become symptomatic and pass the virus on to others without realizing it.

Humans can conduct contact tracing by asking people who have Covid-19 to tell them where they’ve been and with whom they’ve been in touch. It is possible to contact people with the virus by asking them to self-isolate.

If you are positive for coronavirus in England, you will be contacted via the NHS Test and Trace Service. This will happen by text message, email, or phone. People are sent a link to visit the NHS Test and Trace website when they contact them by email or text. This allows them to update their most recent contacts. These details can be sent over the telephone. Contact tracers will ask for names and email addresses as well as the home address and telephone numbers of anyone who might have been exposed to Covid-19.

Contact tracing will contact people at risk for contracting the virus and tell them to isolate for 14-days. It doesn’t matter if someone is ill, they should isolate. It will be illegal to isolate yourself after being contacted by Test and Trace. The government can also issue PS10,000 fines for those who violate the rules.

What is the working principle of the NHS contact tracing application?

Contact tracing apps are designed to help you automate the human process using your smartphone. An app that alerts people about their exposure can be more effective than human contact tracers in alerting them of people with Covid-19. Apps could theoretically be useful tools to help people isolate themselves and reduce the spread of the virus. Problem is? The main problem is that contact tracing apps have not been proven to be effective.

Like other similar apps, the NHS contact tracing app uses low-energy Bluetooth to locate nearby phones (these are called encounters). To estimate distance between two people, the app uses Bluetooth signal strength to determine their proximity. The system can send alerts to anyone who has tested positive for Covid-19. These alerts inform people to self-isolate.

Not all people will be notified to self-isolate. Notifications will only be sent to those who have been identified as high-risk contacts. The app will notify only high-risk contacts based on a small amount of data. However, if someone has tested positive for the virus for more than 15 minutes, they are likely to be at greater risk.

The app uses Bluetooth strength, distance and time to calculate people’s risk scores. It also collects details about their symptoms and when they started. These scores are based on data that can be entered into the NHS app. Distances used to calculate risk scores can be divided into three groups: close (within 0-2 meters), medium (2-4m) and far (further beyond 4m). These distances may not be exact as actual measurements can vary depending on where you live and where your phone is.


The NHS provides details about its algorithm . It states that distance between people is measured every five minutes. The length of time you spend with a person over an entire day determines the risk level. The app’s team can also change the threshold for the risk score. This threshold is based upon the R number. It is designed to reduce false positives and testing.

The NHS contact tracing application collects very little personal data. It is free to download from Apple and Google’s respective app stores, and users don’t have to create an account. The app doesn’t require users to enter their names, email addresses, or phone numbers. The app doesn’t collect location data via GPS.

The app will ask for some data when it is first opened. It also requests permission to use certain features of the phone. The app asks for your first part of your postal code (SW16), so that NHS officials can analyze where the app is downloaded and provide updates on risk. The NHS states that this data will be used to determine where the virus is spreading and how fast it spreads in different areas.

The app will ask permission to use Bluetooth so that contact tracing technology can work. It will also ask permission to access a smartphone’s camera so that people can scan QR codes.

How does an app work if it doesn’t collect any personal data? Two different codes are used to operate the system. It creates a new code each day for your device, which is then stored on your phone. Every 15 minutes, it generates a random code which is shared with other Bluetooth-enabled devices. After 14 days, all codes are deleted.

If someone is positive, they can share their daily codes with other users of the app. This is done by the app sharing your phone’s codes with a central Department of Health and Social Care (DHSC), server, which then pushes the codes out to all other phones with the app. After 14 days, any codes sent to DHSC servers are deleted. If matches are found and there is a high risk score, the alert will be sent to inform people that they have been in touch with someone who has tested positive.

The app will automatically generate a code for people who book tests via the app. This code allows them to link their test results to the app. These test codes can be deleted within 24 to 48 hours of being created.

This app doesn’t only track Bluetooth contacts, it also has other features that make it different from other apps. The app allows users to compare their symptoms with a list of Covid-19 indicators that has been provided by England’s chief physician. This includes high temperatures, new continuous coughs, changes in taste and smell, and many other symptoms. Symptoms will indicate whether someone will need self-isolation.


You can also order a test via the NHS Test and Trace website. The app will show you how long it takes for people to self-isolate if they do so. It can also provide information about risk levels in your local area based on the first portion of your postcode.

QR codes are the way that the app stands out from other apps around the globe. It can scan QR codes at venues using an in-app camera, which will require permission. You can also log where you’ve been by using the in-app camera. Pubs, restaurants, and other venues can now create their own QR codes using a generator hosted on the government’s website.

The QR codes, like the rest of the app don’t transmit any information to a central server. They also don’t store personal information. These codes are used to help people remember where they were, and to inform contact tracers about their activities. You can turn the QR code function on or off within the app. It’s also possible to delete any records created.


QR code check ins are saved on a phone for 21 day – this gives 14 days for the virus and seven days for people most likely to become infected.

Why does the app send multiple notifications at once?

Notifications should be sent to people only if they are in contact with someone for longer than 15 minutes or at a distance less than two metres. This is the threshold that the app uses to alert people about possible Covid-19 exposure. In such cases, people will be asked for self-isolation.

The NHS app can send notifications to people even though they don’t need to be isolated. Exposure logging and exposure notifications can be sent by Google-led systems to Apple and Google. These notifications may indicate that people have been exposed. These are the default messages from Apple and Google technology, according to the NHS. Clicking these messages does not result in anything.

These phantom notifications caused confusion over people’s exposures to Covid-19. The NHS app now sends a second notification at the same moment. It says, “Don’t worry. We have assessed your risk and you don’t need to take any action at this point.” According to the Department of Health, people need to self-isolate only if instructed to by the app.

What happened to the original NHS contact trace app?

This is the second version. It was released as the NHS contact tracing application in September. The first version of the app failed to work after months of testing in Isle of Wight. England chose to develop its contact tracing app on its own and rejected technology from Google and Apple.


Officials from the NHS decided to create a centralised system that would allow data from phone calls where symptoms were reported to be sent to a central database. The NHS tried to implement Bluetooth contact tracing on its own but it could not achieve the same accuracy as using software from Apple and Google.


It was discovered that the original app failed to recognize iPhones during testing. Apple’s iOS forced the app to the background, and it was unable to detect 4 percent of iPhones it made contact with. This compares with 75% of Android phones. The UK tests showed that the Apple and Google systems detected 99 percent of handsets.

The second version of the app for England uses Apple and Google technology. It favors a decentralised approach where data isn’t stored on a central server. Instead, all data about individuals’ interactions is stored on their individual phones.

What are the roles of Apple and Google?

The NHS app is based on the ecosystems of Apple, Google and Google. To conduct Bluetooth contact trace, the app uses both the Apple and Google exposure notifications system. This API is required to use the Android and iOS operating system’s latest versions.

The API was created by Google and Apple in the early days of the pandemic. They wanted to make sure that as little data as possible was collected. Companies have favored a system that protects people’s privacy. This is partly to prevent Bluetooth contact tracing technology being misused maliciously.


The exposure notification system, which is part of Android and iOS, can only be activated if it has an app from the government or health services installed. This system generates codes that link phones to other devices and allows them to interact with each other.

The NHS states that “the functionality of the Google/Apple API has been evaluated alongside rigorous testing the original app.” “The government determined that the Google/Apple approach was most likely to achieve the stated goals while collecting as little data as possible.”

Is the app mandatory?

The download of the NHS contact trace app is optional. The app offers an option to disable the contact tracing setting. This is recommended for healthcare professionals.


If you don’t want to use the app anymore, you can delete it. The app can be removed from a phone without receiving any notifications. All data on the phone will also be deleted.

What happened to my data and who built it?

Dominic Cummings is not the one who made this app. Under the direction of DHSC, the app was developed by NHSX and NHSX. The app was developed by a variety of other organizations.

The NHS published a list listing all organisations involved in the app. Working on the app, the UK’s National Cybersecurity Centre provided technical assistance. Gaby Appleton (ex-director at Elsevier academic publisher) is leading the app’s development. Appleton assumed management of the app’s development in October, replacing Simon Thompson, an Apple executive.

Full Fact pointed out that Serco is not involved with the creation of the app. While the outsourcing company was involved in other aspects of the test-and-trace programme, it did not create the app.

The entire source code for the app has been made open-source and is accessible on GitHub . On the government’s site, you can also find a privacy notice as well as a data protection impact assessment . These documents provide details about how the app handles data and the methods used to create them. These documents were not made public until the app was tested.

The app may collect four types of personal data, which can lead to an individual’s identification. These information can be classified as personal data under data protection laws. These include the postcode entered when installing the app, symptom data, QR code data, and two codes that are generated to allow the contact tracing system software to function. The privacy documentation of the NHS states that “The App was designed to use as few personal data as possible.” All data that could be used to identify you directly is stored on your phone, and it is not shared with anyone else.

The NHS claims that its central system has been hosted by Amazon Web Services and The Health Informatics Service, (THIS). This service is located at Calderdale and Huddersfield NHS Foundation Trust and provides test results to the app. The app has been secured against any third-party tracking that could gather personal information.

App users are not allowed to share their information with any human-led contact tracing efforts in England. According to the app’s privacy policy: “An alternative is to give app users the option to send data stored on their phones to contact tracers.”

How does the NHS contact tracing application work?

The big question is whether the contact tracing app works. Bluetooth contact tracing has been used only during the pandemic, and it is not yet proven to work.


The app is not without risks. It is important to note the rate of false positives. These are situations where the app thinks people should self-isolate, but the prediction is wrong. The original version of the app was designed to allow people with coronavirus to self-diagnose, but the second uses test results. Although this reduces the possibility of malicious activity, there is still the risk of false positives. The app still uses self-reporting to check symptoms.

There is a possibility that measurements could be wrong because Bluetooth was not designed for contact tracing. There is no evidence to show how the system works when objects get in the way of Bluetooth signals. This could mean that people might be asked to self-isolate because they are close to someone with Covid-19. It is not clear if risk scores should differ when people are outdoors, as there is less risk of transmission.

The app must be downloaded and used as much as possible in order to be effective. This will be a major factor in establishing trust in the government. The University of Oxford discovered that 60 percent of smartphone users would download and use a contact tracing application to stop the epidemic at the beginning of the pandemic.

According to the latest modelling by Oxford University researchers and those from Google and Stanford University (Google and Stanford University), apps may not have to be downloaded as often to be effective. The researchers wrote that they found that digital exposure notification systems could reduce deaths and infections by around eight percent and six percent in a model with 15 per cent of the population. This study was done using contact tracing technology from Washington State in the US. Researchers believe that the system can be made even more efficient if it is combined with human-led contact trace.

The research paper concludes that “our results suggest both interventions are useful in counterbalancing effect of reopening but are not completely sufficient to offset new case except at very high levels adoption and manual trace staffing.” “We believe that social isolation and the limitation of person-to-person interaction is crucial.”

One small step in reducing Covid-19 spread may be contact tracing apps. Solid testing and human-led contact trace systems are equally important. To stop the spread of the virus, all of these elements must be in good working order.

AFP has crunched some data about the success of other contact tracing applications. The German app was downloaded 17.8 million times by a population of approximately 83 million people. It also sent hundreds of alerts in July.

France’s app was downloaded more than two million times in August and sent 72 possible contact alerts. Switzerland’s app has been downloaded by 1.6 million people out of an estimated 8.5 million population. It also has 155 positive declarations and has had some success in Italy with 5.4million downloads. 20% of Finland’s users downloaded the app within one day.


Singapore is the country with the highest number of downloads. It was the first country to offer a contact tracing application. As September 9, the TraceTogether app has been downloaded more than 2.4 million times. This represents 40% of Singapore’s total population. A Bluetooth token, a wearable device that can be used for contact tracing, has been trialled in Singapore.

Updated October 22, 2020 at 11:45 BST. This article is constantly being updated with the most recent information on contact tracing in Britain. This article was published at 10:30 GMT May 5, 2020.


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