Started because blood test showed low level, which at my age is bad for bone health. Now every 6 months when I get it tested it is good. Also have always taken Vitamin C, Vitamin A and Zinc. Plus I am fully vaccinated and yes, I wear a KN95 when indoors except when eating in a restaurant which is a rare occurrence these days.
Maybe the mask helps, I don’t know, but it doesn’t hurt. If I worked someplace where I had to wear it 8 hours a day I doubt I could stand it. I reuse the masks by having 7 which I rotate each day.
I may die from Covid next week, but I am doing my best to avoid that.