“ALL diseases target the older, less healthy populations first. Been that way since the dawn of life on earth.”
Not entirely true. The 1919 flu outbreak, for example.
No, the 1918 influenza outbreak still killed far greater numbers of older people and those who were already medically compromised, and thus weaker, than those who were young and physically fit and more capable of fighting it off. It was not a truly high mortality rate infection, nor one that afflicted every person infected to the same degree. The point is the better shape one is in, physically, organically, and in what stage of life, determines one’s body’s system’s ability to both resist and recover from diseases. The outbreak in 1918 was no different. Incidentally, this is true of toxins as well. A dosage that will kill a fit elderly person might not kill a fit younger person of the same body mass.
On the other hand, older people have gained a lifetime of exposure to a far greater variety of pathogens and their immune systems may be able to modify an existing antigen from an earlier encounter to a newly mutated bug’s ancestor more easily to counter the worst effects of the new strain’s efforts, slowing its assault on the cells of the body, giving more time for a proper defense to be mounted.