EmergenC is a good thing to take everyday to help you fight nasty illnesses. It boosts your immune system and gives you energy. Airbourne is good to but emergenC "to me" taste better. As well if her place isn't clean LEAVE! If she is not offering you to clean up before hand or offering you hand sanitizer you should be concerned. IMHO.
I cant remember the last time I had the flu, and I dont get my flu shots I just eat healthy and take my vitimins and Im great... I keep away from people who are sick so it doesnt pass to me.