Basically what COVID-19 does is bind to receptors in the delicate tissue of your lung’s air sacs. This prevents oxygen from crossing the barrier into the bloods

Basically what COVID-19 does is bind to receptors in the delicate tissue of your lung’s air sacs. This prevents oxygen from crossing the barrier into the bloodstream. What makes it worse is that your own immune response, which comes to try and fight the virus, ends up causing more blockages. What these articles are unclear about is why this is “permanent”. But a guess is that it’s like fibrosis where the tissue is permanently hardening — like layers and layers of hardening paint on the interior walls of your house. The aggressiveness of your immune response might be a variable that explains why some people get this worse than others — just a guess. Inflammation, like with so many things, seems to be a big factor. This might be what’s happening with all the heart problems, but again no one is sure about anything at this stage.