CHAPTER 7: Clinical Epidemiology of Coronavirus Disease 2019: Infectivity, Clinical Spectrum and Presentation, and Population Distribution

Coronavirus disease 2019 (COVID-19) is a new infectious respiratory disease that has caused the ongoing pandemic and a worldwide public health emergency. The primary purpose of this chapter is to describe the evolving clinical epidemiology of COVID-19, including (1) infectivity and testing, (2) the clinical spectrum including the classification of clinical type, asymptomatic cases, severe cases and comorbidity, and clinical and immunological response, (3) regional variation in clinical presentation, (4) population distribution by age, sex, and occupation, and finally (5) case-fatality rate. This content may provide useful information on clinical types and presentations of the disease, which may help define clinical outcomes that can be used for the development of prevention strategies and clinical studies or trials aiming to test potential new therapeutics or products for different patient populations.