Lung damage is a bad way of putting it. What they have are radiographic findings which do not indicate any long term problems or damage. This also occurs in other pneumonias. It is impossible to tell how clinically ill someone is by looking at their CT scan. Same with no infectious things such as blood clots and the like.
If you managed to CT the lungs of 1000 random people of various ages and ethnicities, 1 each from a different town in a large state, what is your best guess as to what you find?