After completing an MSc from Scuola Normale Superiore and a PhD in theoretical particle physics from SISSA, Dr Ferretti moved to Barcelona, Cologne and Paris to focus on population genomics. In 2015, he moved to the Pirbright Institute (UK) to study dynamics of pathogens and viral-host interactions. Ferretti's current research at the Big Data Institute in Oxford involves an interplay of epidemiology, genetics, evolution and within-host dynamics of HIV and other viral pathogens such as FMDV and ASF. Abstract: There is an ongoing public debate about mobile apps for contact tracing. Their implications in terms of privacy and data security are under intense scrutiny by cybersecurity experts, lawyers and politicians, as well as the general public. Unfortunately, the most important questions are often absent from this debate: what is the epidemiological rationale behind the suggestion to deploy such a risky tool? Which role would these apps play in the control of the COVID-19 epidemic, and why are they so relevant? In this talk, I will present the scientific arguments underpinning the answers. I will summarise our understanding of COVID-19 epidemiology and SARS-CoV-2 transmission and I will discuss the challenges of different containment strategies for this epidemic. In this framework, I will highlight how speed and efficiency are the main determinants of the effectiveness of contact tracing in controlling the epidemic, and why digital solutions are the most promising ones. I will also discuss current limitations and challenges of app-based approaches. The talk (approx. 30 minutes) will be in a webinar format, with an introduction by the Director. A question/answer session will then be moderated by Prof. Matteo Marsili from the QLS Section. PLEASE REGISTER AHEAD AT THE FOLLOWING: https://zoom.us/webinar/register/WN_hVd-EXGkSMeZIhp0nzwTjQ After registering, you will receive a confirmation email containing information about joining the webinar. The recorded version of the talk is available on the ICTP YouTube Channel at: https://www.youtube.com/watch?v=xXcE-FO-1Nc