By Marietje Botes
The most effective way to stop the spread of a virus is to prevent contact with everyone who is infected. Those who are infected can be isolated and treated if necessary. To determine who they are, it’s necessary to actively look for and manage cases.
During the Covid-19 pandemic, emerging technologies are being repurposed to help trace whoever has been in contact with an infected person.
Some of these technologies, such as the Global Positioning System (GPS), wi-fi and Bluetooth, are not new. GPS has been used to find accident victims at precise geographic locations.
Now, these tools can also help do one of the most important jobs in the pandemic: track and trace. They allow people some movement and economic activity, with the ability to manage their own risk of being exposed to possible infection or spreading it.
The government recently introduced a mobile application, Covid Alert SA, to help people notify their close contacts if they are infected.
The app is based on smartphone technology enabled by readily available functions developed by Apple or the Google Exposure Notification System. It uses a phone’s signal to generate a random code. The code is then exchanged with other users of the same app within a two-metre radius. These codes are stored on the respective devices for two weeks.
People testing positive for Covid-19 in these two weeks can anonymously alert others by just clicking a button.
The exchanged and saved codes will, when activated this way, locate and match each other and alert whoever the infected person has been in contact with. This information will allow people to test for Covid-19 and isolate, if necessary, to prevent further infections.
But there are concerns about accuracy, privacy and integration across regions. Questions have also been raised about whether the uptake will be sufficient for the app to function.
In a recent analysis, my colleagues and I looked at the legal and ethical aspects of tracing people who might have been in contact with an infected person. Our analysis may provide useful insights when deciding whether to use the app and help people understand tracking and tracing principles.
The first concern is the accuracy of the technology. This matters because people’s freedom of movement and the ability to go to work or attend school will be affected by an alert.
Cell tower metadata are supplied by electronic communication service providers. The data rely on the signal strength and delay times to triangulate the position of a cellular phone. This method often provides inaccurate information because signals are scattered by buildings. There aren’t many towers in rural areas, so triangulation may not even be possible there. There’s also concern the app might not detect other nearby smartphones accurately.
But there’s no evidence to suggest that the app is not working.
Second, there’s the issue of privacy. But for purposes of managing a pandemic,there are apps that have been tried and tested and evolved to the point where they can do more good than harm if used on a large scale.
Marietje Botes is a post-doctoral researcher at the University of Pretoria.
The Star