- patients who had a normal lung imaging examination (radiography, tomography, etc.) at discharge. - diffuse parenchymal lung disease before pandemic - cystic bronchiectasis - presence of contraindications for systemic corticosteroids (uncontrolled diabetes, uncontrolled hypertension, unstable angina pectoris, history of acute coronary syndrome at last month, presence of active infection, active peptic ulcer, presence of uncontrolled psychiatric disease, etc.) - decompensated heart failure - contraindications for pulmonary function tests and those who cannot cooperate with the test - younger than 18 years old - pregnant women - breastfeeding women - those who do not give written consent

- patients who had a normal lung imaging examination (radiography, tomography, etc.) at discharge. - diffuse parenchymal lung disease before pandemic - cystic bronchiectasis - presence of contraindications for systemic corticosteroids (uncontrolled diabetes, uncontrolled hypertension, unstable angina pectoris, history of acute coronary syndrome at last month, presence of active infection, active peptic ulcer, presence of uncontrolled psychiatric disease, etc.) - decompensated heart failure - contraindications for pulmonary function tests and those who cannot cooperate with the test - younger than 18 years old - pregnant women - breastfeeding women - those who do not give written consent