Clinical presentation and course of COVID-19.

Information about the clinical presentation and course of COVID-19 is evolving rapidly. On presentation, cough and fever predominate, but extrapulmonary symptoms are also common; in some patients, loss of sense of smell may be an early but favorable sign. The mortality rate varies widely in different reports but should become clearer as more data are collected. Risk factors for severe disease and death include comorbid conditions such as hypertension, cardiovascular disease, diabetes mellitus, and chronic obstructive pulmonary disease. Other implicated factors include older age, obesity, end-stage renal disease, and a higher neutrophil-lymphocyte ratio.