Mark I admire your honesty in this post, but I cannot believe that the vitamins kept the Covid bug away and give you any meaningful immunity to the virus. Immunity is obtained the hard way like you or by having the Covid vaccinations.
Even with the full Covid shots there is still the opportunity to get the virus. Not having the vaccinations puts you and those close to you in danger of catching the virus from you. Even Mr T said to get vaccinated.
Wear a mask in groups and get vaccinated, who knows the life you save may be your own or someone dear to you.
Get well bud and best wishes, I truly would hate to hear that you were the latest death in the US.