Digital contact tracing is a new public health approach developed and deployed worldwide during the COVID-19 pandemic. Contact-tracing apps measure proximity and duration of close contacts, allowing individuals who have been exposed to SARS-CoV-2 to be rapidly notified. At the same time, these apps represent a novel measurement tool for precision epidemiology. Here we present the main empirical insights from the NHS COVID-19 app used in England and Wales. First, we demonstrate that this intervention had a significant epidemiological impact. Then, we show how such apps reveal unique quantitative insights into individual and population determinants of pathogen transmission. We also illustrate how the app’s capabilities for precision epidemic surveillance at scale offer near-real-time information on epidemic dynamics at unprecedented resolution, focusing on exceptional events such as the Euro football tournament in 2021. Finally, we discuss the importance of precision epidemiology, big data and AI for a rapid response to future epidemics.
Luca Ferretti (Fri,) studied this question.