For decades I used to suffer TERRIBLY from a chest old every winter, sometimes every winter and spring, too. So bad that I could hardly breath.
So bad that I was afraid to leave the house & even go to church, fearful that someone would cough on me. I also caught the Flu every time it was going around.
THEN I discovered Vitamin D3 and I have been free of colds for 8 years. Now, at the worst I might get a sniffle or runny nose. Just 10,000 IU daily was enough to boost my blood level to 75 ng/ml. Also, no more Flu. Now I am fearless going out in the winter or going to church.