Before revision:  I show here these dramatic variations in fatality rates across age and gender are impressively strongly correlated (r^2=0.91 with only one free parameter) with levels of the ACE2 protein in rat lungs, which are in turn qualitatively similar to expression in humans .
After revision:  I show here these dramatic variations in fatality rates across age and gender are impressively strongly correlated (r^2=0.91 with only one free parameter) with levels of the ACE2 protein in the lungs. This correlation also rationalizes the association between Covid-19 lethality and hypertension. Surprisingly, despite ACE2 is the viral receptor, higher values of ACE2 lead to lower fatality .