That is simply not true. I take D-3 supplements these last 8 or so years and have not had any virus in that time. Wife is a primary school teacher. It is the same for her. She doesn't bring that stuff home to me anymore. That goes for members of my congregation at church whom I have induced to use the Vitamin D.
Oh, please. Prove it. Go ahead and inject yourself with live raw influenza virus and see what happens. All the Vitamin D in the world isn’t going to kill influenza virus. Religiously washing your hands and not exposing yourself is what will keep you from catching the flu. Of course, there’s always a flu shot. You may educate yourself on influenza and the flu shot here:
http://www.cdc.gov/flu/about/qa/flushot.htm