Characteristics of Postinfectious Cough

Collect the age, sex and other demographic data of 1600 patients with chronic cough after COVID-19 infection and clinical parameters such as cough characteristics, establish a cohort of patients with chronic cough after COVID-19 infection, observe the type and level of airway inflammation, airway responsiveness, cough sensitivity and changes in microbiology of patients with chronic cough after COVID-19 infection, clarify the epidemiological characteristics, clinical pathophysiological characteristics, long-term prognosis and related factors of patients with chronic cough after COVID-19 infection, explore the clinical pathophysiological characteristics and pathogenesis of cough after COVID-19 infection, and provide a theoretical basis for the treatment of persistent cough after COVID-19 infection.