The corona outbreak shown in a very tangible way the rate of aging and regression of the immune system.

Mortality rates (there is high variability between women and men) complement the strength of the immune system. (Reverse ratio)

The numbers are not very important. They have a very significant statistical estimate (regression). It can be explicitly seen that the decline of the immune system begins more significantly at the age of 45-55, and the rate of decline is not linear (uniform) but exponential.