This is the thing with old age that I think most people won’t understand until it happens to them. The body’s ability to deal with those things severely deteriorates with age. You can be peppy and active one day, and on death’s door the next. COVID has proven to be particularly bad for the elderly, but every “minor” ailment or injury is much more serious, and possibly life threatening given the wrong mix of complications. Biden has probably the best chance being in the position he is, and testing positive isn’t the same as being symptomatic, but he’s by no means free and clear. It’ll be interesting to see how this turns out.