In Reply to: I was definitely sick that long and actually even longer. Shortness of breath posted by for me lasted about 2 months. I haven't been sick since, sm on Wed, Aug 11 2021 at 08:19 AM CDT:
I believe I had Covid back at the start of the epidemic before there was antibody testing available. I never bothered to get tested thereafter, I just got vaccinated after the initial cattle stampede died down along with the number of active cases out there. If I didn't have Covid, I'm now protected, and if I did, I've effectively had a 3rd booster, so good either way.
Vitamins are all well and good, and I do take some on general principles, but they're no guarantee you won't catch an infectious disease if/when you are exposed to a sufficiently high viral load. They may help make your immune system sufficiently strong to recover without a problem, but even that is not guaranteed.