inclusion criteria: * diagnosed to have covid-19 by means of a real-time reverse transcription polymerase chain reaction (rrt-pcr) test performed on a respiratory (upper or lower respiratory) sample or the detection of covid-19 antigen * having significant respiratory symptoms (cough and breathlessness) or persistent hypoxemia or oxygen desaturation on exercise and ct chest showing residual changes of post-covid parenchymal involvement of any extent or having ct chest showing residual changes of post-covid parenchymal involvement \>20% of the lung parenchyma on visual inspection of the scans between 3-8 weeks of the onset of symptoms of covid-19 * willing to participate in the study

inclusion criteria: * diagnosed to have covid-19 by means of a real-time reverse transcription polymerase chain reaction (rrt-pcr) test performed on a respiratory (upper or lower respiratory) sample or the detection of covid-19 antigen * having significant respiratory symptoms (cough and breathlessness) or persistent hypoxemia or oxygen desaturation on exercise and ct chest showing residual changes of post-covid parenchymal involvement of any extent or having ct chest showing residual changes of post-covid parenchymal involvement \>20% of the lung parenchyma on visual inspection of the scans between 3-8 weeks of the onset of symptoms of covid-19 * willing to participate in the study

inclusion criteria: - diagnosed to have covid-19 by means of a real-time reverse transcription polymerase chain reaction (rrt-pcr) test performed on a respiratory (upper or lower respiratory) sample or the detection of covid-19 antigen - having significant respiratory symptoms (cough and breathlessness) or persistent hypoxemia or oxygen desaturation on exercise and ct chest showing residual changes of post-covid parenchymal involvement of any extent or having ct chest showing residual changes of post-covid parenchymal involvement >20% of the lung parenchyma on visual inspection of the scans between 3-8 weeks of the onset of symptoms of covid-19 - willing to participate in the study

inclusion criteria: - diagnosed to have covid-19 by means of a real-time reverse transcription polymerase chain reaction (rrt-pcr) test performed on a respiratory (upper or lower respiratory) sample or the detection of covid-19 antigen - having significant respiratory symptoms (cough and breathlessness) or persistent hypoxemia or oxygen desaturation on exercise and ct chest showing residual changes of post-covid parenchymal involvement of any extent or having ct chest showing residual changes of post-covid parenchymal involvement >20% of the lung parenchyma on visual inspection of the scans between 3-8 weeks of the onset of symptoms of covid-19 - willing to participate in the study