How COVID-19 Contact Tracing Apps Helps Agencies Combat Against Pandemic

Keeping track of people who came in touch with COVID-19 positive people is an important part of preventing the disease spread. However, extensive tracking by the government or health agencies comes with its own set of privacy and data safety concerns. Like most things, a compromise is needed for contact tracing apps to work.

Dozens of countries around the world, including India, Switzerland, Israel, Australia, Singapore, and China have either released contact tracing Android apps or are on their way to do so. While some of these apps, such as the ones used by China, directly share information with the government and the police, others such as the TraceTogether app by the Singapore government use a decentralized method of storing data to protect user privacy.

What is Contact Tracing?

The problem statement for contact tracing is pretty straightforward – identifying people who were in close proximity with infected people and warning them. When someone tests positive for COVID-19, find everyone they’ve come in contact within the last few days and test them too. In the pre-smartphone era this was more or less detective work – interview the patients and make a list of people they talked to and places they visited.

And then go and talk to them and see if they’ve talked to anyone else and warn them too. Doing this, however, requires a lot of manpower, especially when there are tens of thousands of new cases being reported every day. An effective contact tracing system can allow businesses to run, cities to remain open and lockdowns to be lifted, all while minimizing the risk of another wave of infections.

How do These Apps Work?

Most of the contact tracing apps today use either QR codes, Bluetooth or GPS or a mix of these. GPS based contact tracing systems, such as the ones used in Bahrain and Iceland, work by continuously tracking a person’s whereabouts and reporting that to a central server.

Since GPS can accurately identify locations with less than five feet error, identifying people nearby becomes a relatively simple task.

New Zealand’s COVID tracing system was implemented by putting up QR codes at the entrances of public transit stations, buildings and buses – users scan those QR codes before entering, providing a rough set of data on who was in the same place at the same time.

The most commonly used system, however, is Bluetooth based tracing. Whenever users venture into public spaces, the app keeps the Bluetooth on and keeps scanning continuously for other Bluetooth signals.

Whenever it encounters another Bluetooth signal, it saves the other device’s ID for a specific period of time, usually 21-30 days. When someone tests positive, they can mark that in the app, and it’ll send out notifications to all the other devices it encountered in the last few days, and warn them to self isolate.

One advantage of this system is that no data goes to a central server unless someone tests positive – furthermore, user’s exact locations aren’t saved anywhere, unlike GPS based systems.

How contact tracing works
How an app-based COVID-19 contact tracing app would work.

None of these systems is perfect though. China recently came under fire for its Green-Yellow-Red color coding system for each person, based on their risk level to getting Coronavirus. People being marked yellow or red would face restrictions in entering buildings, using transit, and in extreme cases be asked to stay at home entirely.

While this sounds nice in principle, the fact that all of this classification was being done by automated systems, which gave no explanation to its decisions, makes it problemsome. Multiple privacy advocates have warned that contact tracing could be the beginning of the slippery slope where government tracking becomes more and more common.

Yet another problem is that of smartphone penetration. While most of us would assume smartphone usage is more or less universal, there are countries like Egypt, India, and Bangladesh where not even 30% of the population has smartphones.

Even in places with high enough smartphone penetration, unless most of the people venturing out install and use these apps, all of these methods are close to useless. Some countries have tackled this problem by integrating contact tracing with existing apps – China’s tracing system, for example, comes in-built with Alipay and WeChat, which are popularly used apps.

This problem of users, however, is on its way to being permanently solved. Google and Apple recently announced a joint initiative to build a Bluetooth-based tracing system, that would soon become a part of the mobile OS itself, working in the background without having to install any application.

Unlike other Bluetooth based systems that also collect GPS information, this inbuilt system would only use anonymous Bluetooth numbers and would save all data on the user’s device itself.

The Privacy Debate

While the method proposed by Google and Apple contact tracing tool would ensure user privacy is preserved, the greater privacy comes at a cost – lesser information available to health authorities fighting the pandemic.

For governments trying to identify COVID-19 hotspots or places where most transmission is happening, the lack of a centralized data source complicates things a lot.

In which direction the spread of Corona is happening and why? Is there a weakest “Corona-link” that can be broken for maximum impact? Are these occurrences happening randomly or is there a pattern to them?

Answering all these questions becomes much, much harder without a central database. Ultimately, a middle path needs to be taken, balancing the health concerns of a pandemic and privacy of user data.

Rohit Dwivedula
Computer Science student, interested in tech.