The Covid-19 ContacTUM Initiative

The SARS-CoV-2 pandemic has already claimed many lives worldwide and paralyzes public and economic life in many countries. Unfortunately, even though research is being carried out at an unprecedented level to develop an antiviral treatment for COVID-19 and a vaccine against SARS-CoV-2, these are not to be expected soon.

Until effective treatment options are available, we need to use non-medical measures to fight the epidemic. To tackle the current pandemic, an interdisciplinary consortium - ContacTUM - has formed at the Technical University of Munich aiming at three goals: developing a reliable medical self-test, designing a secure and privacy preserving contact tracing app, and understanding better the spread of the virus by modeling the epidemic.

The initiative started in mid-March 2020, literally on the first day of the Government's corona lockdown, when the SFB1258 scientists around Elisa Resconi asked themselves what they could do to help fight the emerging corona pandemic. They started developing the concept for a Digital Contact Tracing Service (DCTS), an application that now is commonly referred to as "Corona App".

Contact tracing that ensures privacy by design

The prime concern of the team was that the app ensures by design the maximum data security and privacy because they anticipated that the efficacy such an app could achieve would primarily depend on the people's trust and acceptance in the tool. Thus, they focused on a Bluetooth-based contact tracing system, that performs the matching between users who have the disease and their contacts on the non-infected users’ phones. This approach is known as the "decentralised" as opposed to the centralised, where the match is done on a central server.

Simulating the effect of mitigation measures with epidemiological methods

A second activity developed around setting up an epidemiological model for simulating the effect of the app and other non-pharmaceutical mitigation measures with Monte Carlo methods, and a third to develop a rapid and reliable medical self-test. To achieve these goals, an interdisciplinary group of scientists from the SFB1258, the TUM Faculties of Mathematics, Physics and Computer Science and the TUM Schools of Medicine and Governance formed under the name of ContacTUM Consortium.

For the DCTS app, a collaboration with ITO evolved, a group of German professionals that joined to develop an open source contact tracing system. The ContacTUM team also got a member of the international TCN coalition, a community of technologists supporting privacy-preserving exposure notification apps during the Covid-19 pandemic.

The DCTS concept was submitted to Bluetooth for review

The ContacTUM & ITO Consortia submitted their DCTS concept for review to the Bluetooth Special Interest Group (Bluethooth SIG) on 7 April (please see also the TUM press release from 24 April). While the German Government initially favored the centralised over the decentralised approach for the German Corona app, a joint statement of international scientists was released on 19 April that urged countries "to rely only on systems that are subject to public scrutiny and that are privacy preserving by design". The statement was signed by the TUM scientists Prof. Christian Djeffal, Dr. Tina Pollmann, Prof. Elisa Resconi and Prof. Stefan Schönert, all of them engaged in the ContacTUM Consortium.

The ContacTUM & ITO app is available for download since May

A prototype app for android devices based on the ContacTUM & ITO concept is avaible for download on the ITO website since May. The publication that describes the principles of the ContacTUM & ITO DCTS "Digital Contact Tracing Service: An improved decentralized design for privacy and effectiveness" is available on GitHub and was submitted for publication. The concept  includes the encryption technology Private Set Intersection Cardinality for improved privacy and second order tracing of contact persons. Detailed information on the DCTS app can be found on the following pages, including information on other DCTS approaches and on the apps officially provided in different countries.

How reliable is the Bluetooth signal as a measure of the distance?

Meanwhile, the German Government changed its mind and commissioned SAP & Deutsche Telekom with developing the official German app following the centralised approach. On 16 June, the German Corona-warn-app was finally released. We consider this as a big step, but our efforts continue. On a pure technical level, there is one aspect that still needs to be better understood: How reliable is the Bluetooth Low Energy signal as a measure of the distance? We are currently looking into this. But also privacy and data protection are issues we are still concerned with.

Publication of a comprehensive modelling study

The results of Tina Pollmann's and collaborators' study "The impact of digital contact tracing on the SARS-CoV-2 pandemic - a comprehensive modelling study" was published on medRxiv.