Health Department launches Covid-19 contact tracing app

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The app is built on the exposure notification application programming interface (API), developed by Apple and Google to enable contact tracing through mobile phones.

The app is fully privacy-preserving, in line with the requirements of the API, and does not collect any personally identifiable information or trace a user’s location.

Using Bluetooth, the Covid Alert SA app emits a randomly generated code that is picked by other users when two phones come into proximity of one another. This unique identifier changes frequently and cannot be linked to the identity of any user. Over time, each user builds an “encounter history” of those they have been in contact with.

When a user tests positive, they are requested to report their diagnosis anonymously in the Covid Alert SA app. When the user does so, all other users with whom they have been in contact for the past 14 days will immediately be notified of their exposure and prompted through the care pathway. At no point in this process is the identity of any user revealed.

Bluetooth-enabled contact tracing apps allow a greater number of contacts to be traced more rapidly, including strangers whom an index case may not be able to recall or identify. The app is zero rated to facilitate optimal citizen uptake.

Breaking the chain of transmission

“Global experience has demonstrated the risk of a resurgence once restrictions on social and economic activity are lifted. While the trajectory of the epidemic in South Africa has stabilised, such a resurgence remains a real and present danger in our own country,” said Dr Sandile Buthelezi the department's director general.

“This technology allows us to effectively break the chain of transmission by dramatically reducing the time between exposure and knowing one has been exposed, so that one can take action by self-quarantining and testing when necessary," he said.

Gaurang Tanna, who led the app development team within the department, said it is a crucial public health intervention to help suppress Covid-19 and prevent resurgence.

“It works best when many people download the app. We request everyone to download the app, and those confirmed positive to report their diagnosis so that their contacts can be notified.

“The app is designed to reduce the impact on the health system and save lives, while preserving privacy at scale. For every 100 infections we are able to prevent using this technology, we could prevent as many as 15-20 hospital admissions,” said Tanna.

The app has passed legal muster for implementation through consultation with Justice Catherine O’Regan, the Covid-19 designated judge.

“The Covid Alert SA app is based on privacy protecting technology to alert users when they have been in close contact with someone who has since tested positive for Covid-19. The more people that download it, the better it will work.

“Learning how to keep everyone safe from Covid-19 is one of the challenges the world faces. I hope that the new Covid Alert app will make a contribution to doing so,” said O’Regan.

Covid Alert SA was developed at no cost to the department, through a partnership with world-class developers at Discovery Health, Apple and Google.

The department expressed appreciation to its partners for their contribution, including the Banking Association of South Africa and its members, as well as mobile networks Cell C, Telkom, MTN and Vodacom.