We must all admit that many technological developments have made this pandemic bearable. Online meeting apps helped many employees to resume their work from home, to let students attend their classes etc. Many apps are there to interact with your friends, you have OTT platforms for entertainment etc. But how long can this go on? Not all jobs can be done from home. Some companies have called their employees back to work. Some countries have already reduced the restrictions on various public places. If not today, a day will come when we have to go back to the way things were. How can we be ready to face COVID-19 every day then? Are COVID-19 apps the answer? 

COVID-19 apps are becoming guides for all the employees who have to step out of their (safe) houses into an unpredictable world. Today, let us look at how these apps work.



Contact tracing is the process of finding all the people that the infected person has been in contact with before he/she has been tested positive for a virus. It is an important tool to control the spread of any virus. Manual Contact tracing does not work for communicable diseases like COVID-19. When a person gets tested positive for COVID-19 virus, the government ensures that his/her family and friends are home quarantined, but how can you get in contact with a person he/she sat next to in a bus, and inform them they have been exposed to the virus? 


So, COVID-19 apps offer us Digital contact tracing. Digital Contact tracing is a process to trace all the people, an infected person was in contact with, by using tracking systems like GPS location and Bluetooth. Most of the COVID-19 apps are using both GPS (Location contact tracing) and Bluetooth (Bluetooth contact tracing). 

How does the app work?

Whenever a user installs a COVID-19 app, he/she must agree to keep the smartphone’s Bluetooth and/or GPS turned on. 

Let’s discuss how Digital contact tracing works. Consider two people A and B. They both have the same COVID-19 app on their smartphones. This COVID-19 app employs Bluetooth contact tracing which means that the app uses Bluetooth to emit anonymous time-shifting identifiers to nearby devices. Now back to the story! Both A and B turned on Bluetooth in their respective phones. Imagine they both go to the same coffee shop. Now when B’s phone comes into the proximity of A’s phone, due to COVID-19 app, they both exchange each other’s Bluetooth key. A’s Bluetooth key is stored in B’s phone and vice-versa. 

Unfortunately, B has been tested positive for COVID-19. B updates this information in his COVID-19 app. After this update, the app’s server checks all the Bluetooth keys in B’s app and traces all the people B has been in contact through these keys and alarms them. Thus, A gets a message that she may be infected and she should get tested immediately for COVID-19.

Recall that A and B met in a coffee shop. If the COVID-19 app uses Location contact tracing, then instead of Bluetooth key, the app stores all the locations that B visited. When B updates that he is tested positive for the virus, the database sends an alarm to all the people who have visited any of the same places as B. Thus, A gets a message that she may be infected and she should get tested. The government can also send orders to clean the coffee shop or shut it down for a few days.

Centralised or Decentralised COVID-19 apps?

So, if we go back to the story of A and B, I mentioned about the app’s server. Should this be a centralised or decentralised server? If it is a decentralised server, the COVID-19 app-only forwards the user’s ID or Bluetooth key to the COVID-19 app’s server. If it’s a centralised database, then it forwards the user’s key and all the IDs or Bluetooth keys collected by the app to the main server. 

Some tech experts say that centralised COVID-19 apps pose a threat to the privacy of users. They claim that then the country’s government has mass-surveillance on the citizens, has access to their location data and data with all the people they came in contact with. So, to help various countries to build a decentralised COVID-19 app that works on both Android and iOS platforms, Google and Apple collectively launched Exposure Notification API. 


Digital Contact Tracing in various countries:

  • Singapore’s government came up with a contact tracing protocol called as BlueTrace which powers their tracing app TraceTogether. BlueTrace protocol is also adopted by Australia’s CovidSafe app
  • In South Korea, they used non-app digital contact tracing. In this process, they used the location data and card transaction data of infected patients and then predict all the people who have been exposed to the virus.
  • In China, the government has made it mandatory for all citizens to install the government’s health tracking app. There are QR codes present at every store or market. When a person scans the QR-code and the health status is green, he/she is allowed to enter the store and not allowed if the health status is red in colour.
OR Code based health app in china
  • In England, the government launched NHSx app for COVID-19 contact tracing. 
  • In Germany, the government has recently built “Corona-Warn-App” which uses decentralised contact tracing and uses Exposure Notification API provided by Apple and Google
  • Similar to Corona-Warn-App, Italy’s Immuni, Switzerland’s SwissCovid, Japan’s COCOA and many other countries are optimising their COVID-19 apps to work along with Exposure Notification API.

Aarogya Setu:India’s Covid-19 contact tracing app

Now let’s come back to India. I am sure that every Indian knows about India’s COVID-19 app, Aarogya Setu. To back this up: Aarogya Setu app was downloaded by 100 million people in less than 40 days. The app is available on Google Play Store and iOS app store.

Aarogya Setu APP

Features of Aarogya Setu App: 

  • Aarogya Setu app uses both Bluetooth and GPS location for contact tracing. When two smartphones with this app come within Bluetooth proximity, they securely exchange a digital signature of this interaction including time, proximity and location.
  • If any of the people you come in contact with tests positive for COVID-19, Aarogya Setu app calculates your risk of infection based on the recency and proximity of contact you had with the infected person. It also communicates this risk to you via the app or through a notification.
  • Aarogya Setu app assures the users that it anonymizes their data by assigning an anonymous, randomized unique number (DiD) and associates it with the user’s mobile number. It does not reveal the details of the infected people or their medical condition to any other user or to the public.
  • All the contact tracing and location information that is collected is stored locally on your phone and it is only uploaded to the Aarogya Setu server if you have been tested positive for COVID-19.
  • It also gives COVID-19 updates to users and helps them in self-assessment i.e. identifying COVID-19 symptoms and their risk profile. The app tells you how many COVID-19 positive cases are likely in your radius.


Contact tracing is a potentially privacy-invasive technology unless appropriate measures are employed. And appropriate measures are being taken by the governments united with tech giants like Google and Apple. Now, it is made possible to keep people informed about their exposure to COVID-19 when they are out in the world in the form of COVID-19 apps. 

COVID-19 apps are becoming informants to people about their exposure to the virus when they are resuming their earlier lives.

For More Please Visit Our Site and Subscribe to Our News Letter!


Please enter your comment!
Please enter your name here