Daily D3 to prevent flu and colds. Has worked for me for 16 years. It also mitigates WuFlu. Everyone who has been in ICU for Chinese flu has been deficient in D.
I take D3 twice a day. Single dose is 2000 I think. No cold for years, but if I think there is any sign, then I add Coldeze.
I’ve been taking 20,000 IU’S of D3 for over a year now....Not one cold or flu symptom.