Effect of ozone therapy in post COVID-19 lung sequels

INTERVENTION: Intervention 1: Intervention group: Patients referred to ozone therapy centers affiliated to Baqiyatullah University located in Tehran and Najaf Abad, with a history of contracting COVID‐19, who have been discharged from hospital with hypoxemia and oxygen dependency, will be included in the study. The therapeutic dose is 35‐50 micrograms/mL with a volume of 120‐240 cc of blood and its equivalent O2/O3 mixture for 5‐20 sessions, based on the inflammatory factors and severity of lung involvement and hypoxia at the time of referral, the exact amount of the dose and the number of sessions is selected. The first sessions will be daily and then alternate in the week. Intervention 2: Control group: This group receives standard treatment including prednisolone or pirfenidone. These patients were admitted to the hospital and referred to the relevant medical centers and received appropriate treatment and were included in the study under the name of control group. Normally, the dose of Pirfenidon for the first week is 267 mg daily, for the second week, 534 mg, and from the third week (maintenance treatment) 801 mg. Maintenance treatment is selected based on the condition and severity of the patients involvement. Prednisolone is usually 1mg/kg daily, which can be changedbased on the patient. CONDITION: Condition 1: Post COVID fibrosis/ inflammatory lung disease. Condition 2: COVID‐19 disease. ; Abnormal findings on diagnostic imaging of lung ; COVID‐19, virus identified U07.1 PRIMARY OUTCOME: Spirometry diagram. Timepoint: At the beginning of the study and 6 months after the received treatment. Method of measurement: Interpretation of spirometry. The percentage of improvement of pulmonary involvement in CT scan reports of patients. Timepoint: At the beginning of the study and 6 months after the received treatment. Method of measurement: CT scan report of patients. INCLUSION CRITERIA: Filling out the informed consent form Post COVID‐19 oxygen dependent patients