I've stayed on a regiment of C, D3, zinc, quercetin, I haven't heard of K2 before. I also keep bottles of Providone Iodine handy. 10% Providone, mix 1 1/2 Tablespones PI with 25 cc or ml of distilled water and use cotton swabs to swipe inside the nasal cavities. I use it if I am going into a crowded area like a festival , or real up close visits like dentist. You can get it at Kmart for 10 bucks a bottle, one bottle last forever, if you ask the pharmacy they'll probably give you a free dropper also, they gave me like three of them for free. Than it'd be 1 cc PI to 9 cc distilled water on the dropper. It keeps viruses from attaching through the nasal cavity according to American Front Line doctors.