This lecture by Prof. Marcel Salathé from EPFL covers the COVID-19 outbreak, including the terminology, transmission modes, severity, and mitigation strategies. It discusses the basic and effective reproduction numbers, case fatality ratios, and the importance of mitigation in minimizing transmission. The lecture also explores the challenges posed by infectious diseases, the impact of comorbid conditions on severity, and the global response to the pandemic. It provides insights into the epidemiological characteristics of COVID-19, the distribution of cases worldwide, and the efforts towards vaccine development and outbreak control.