Clinical Research Directory

Inclusion Criteria: 1. Age ≥18 years old; 2. A clear history of COVID-19 infection with a positive nucleic acid or antigen test before chronic cough; 3. Persistent cough for more than 8 weeks after the acute phase of COVID-19 infection has disappeared; 4. Chest X-ray and/or chest CT without significant evidence of lung disease; 5. No history of chronic cough (\>8 weeks) prior to COVID-19 infection. Exclusion Criteria: 1. The patient refused pulmonary function and blood tests; 2. The patient has previously been diagnosed with respiratory diseases with cough as one of the main symptoms, including cough variant asthma, allergic bronchitis, eosinophilic bronchitis, gastroesophageal reflux disease, chronic obstructive pulmonary disease, chronic bronchitis, bronchiectasis, interstitial lung disease, pulmonary/tracheobronchial tuberculosis, etc.; 3. Patients who are pregnant or breastfeeding; 4. The patient's medical records are incomplete; 5. Patients lost to follow-up.