Is it possible that an immune system can be overused and all I needed to do is give it a break for ~6 months which happened during lockdown. Now given that break, perhaps I have a super immune system after over-training it for so many decades. Maybe ?
More likely it has to do with these habits I developed:
1) Breathing almost exclusively through my nose and holding my breath when passing people especially if they cough or sneeze.
2) Drinking water with 1+ gram of vitamin C powder and 5000IU+ of Vitamin D _everyday_without_fail.
3) Not drinking in bars past 10PM and sleeping ~7.5hrs every day.
4) Eliminating the gym. As an aside I have one kettle bell, a pull-up bar, and several bands. To my surprise, I am built like Daniel Craig with more definition from just ~3 ~seven minute mid-intensity workouts through out the day.
5) Hyper conscious to not touch my eyes or face.
Does anyone else have a turn-around story like mine ? Or are most of the people who didn't get Covid the type who never get sick? For the record I am vaccinated. As a counter-anecdote to my second question, my dad, also vaccinated, hasn't been sick over a decade until he got a mild case of Covid a few months ago.