I thought it was lowered expression of the receptors covid-19 binds to (known condition among smokers) ace-2... Because smokers have suppressed ace-2 while smok

I thought it was lowered expression of the receptors covid-19 binds to (known condition among smokers) ace-2... Because smokers have suppressed ace-2 while smoking but a higher baseline; they are protected from getting it because when they are in public they are likely smoking and protected but once they get it they get very severe COVID... I mean it's all kind of a just-so story. Iirc Omeprazole which also depresses ace-2 failed as a prophylactic treatment