Inhaled Mesenchymal Stem Cell-Derived Exosomes in the Treatment of Post-Infectious Cough: A Single-Center Randomized Controlled Clinical Trial

Inclusion criteria

• Patients aged 18-60 years.
• Diagnosis of post-infectious cough, which is defined as: after the symptoms of acute respiratory infection have disappeared, chest radiographs are normal, irritating dry cough or cough with small amounts of mucoid phlegm occurs, cough persists for 3 to 8 weeks, and other causes of cough are ruled out.
• Baseline cough visual analog scale>=60mm.

Exclusion criteria

• patients with any other disease that causes coughing (eg, Upper airway cough syndrome, eosinophilic bronchitis, gastroesophageal reflux cough, bronchial asthma, chronic obstructive pulmonary disease and bronchiectasis).
• Patients with serious lung diseases (eg, lung cancer, tuberculosis or pulmonary fibrosis).
• Patients with serious comorbidities, (eg, cardiovascular, cerebrovascular, liver, kidney or hematopoietic system diseases or other serious primary diseases)
• Current or ex-smokers quitting smoking for less than 6 months.
• Patients with a body temperature ≥37.3℃.
• Patients with white blood cell count or neutrophil count is higher than the upper limit of normal.
• Patients with abnormal chest X-rays.
• Patients Suspected or confirmed history of alcohol or drug abuse or mental illness.
• Patients with pregnancy, lactation or planning pregnancy.