The long term effects of Covid 19 on lung function are still being found. It is really too early to know what the real long term consequences will be and what symptoms and problems many patients will have years from mow. Keep in mind that the long term effects of Covid 19 include problems with the musculoskeletal system, neurologic impairment, cardiac symptoms, blood and kidney issues, gastrointestinal problems, gynecologic consequences and even skin issues.
As far as the lungs are concerned, most of the findings involve scarring of lung tissue and injury to the larger airways of the lungs in the form of an anatomic deformity of these airways caused by inflammation. The name for this airway deformity is bronchiectasis.
Both of these long term findings in post Covid 19 patients potentially have long term consequence that could last for decades. There is some data to suggest that some patients with post Covid 19 scarring on cat scanning of the chest may have progressive disease that may actually result in the need for transplantation. Likewise, the airway distortion of bronchiectasis leads to chronic lung infections, chronic cough and mucous production, bleeding and reduced quality of life.
It is important that anyone with a history of a moderate to severe Covid 19 infection have some regular pulmonary follow up even if current cat scans are normal and, especially, if they are not. The jury is still out on what is going to happen to these patients over their lifetime