I have more knowledge in nutrition than medical treatment but it seems the people seeing the severe cases have the highest initial inflammatory to start with with a lot stemming from obesity. It has been years since I have looked at the inflammatory markers but they were always higher in people with obesity, diabetes, high blood pressure, etc. and COVID combines to cause a cytokine storm.
Is this the case doctors? To me the best thing anyone can do right now is to get their fat levels down and exercise. With 2/3s of Americans being overfat this is not a good sign for things to come. Alcohol also causes a ton of inflammation and seeing as alcohol sales are through the roof that is not good.