In this link
https://www.dw.com/en/covid-19-recovered-patients-have-partially-reduced-lung-function/a-52859671
we can see
Now researchers in Hong Kong have said that recovered coronavirus patients can be left with damaged lungs.
A small study of 12 patients discharged from hospital showed that two or three had reduced lung function. However, it is too early to confirm any long-term effects.
"In some patients, lung function could decline by about 20 to 30% after recovery," says Dr. Owen Tsang Tak-yin, medical director of the Infectious Diseases Centre at Princess Margaret Hospital in Hong Kong.
Computer tomography have shown fluid- or debris-filled sacs in the lungs, which may get progressively worse as the illness develops.
What can determine the long term effects?
Why can this:
"In some patients, lung function could decline by about 20 to 30% after recovery," happen?
Are elderly more likely to this? or it could happen to anyone?
Does this only happen if you had severe symptoms?