Stomach flu prevention

Hey guys! I know flu season is almost over, but I thought I'd share this with you. So, a few weeks ago, my little sister threw up, and my mom was freaking out a little. There's 10 kids in my family, so when one of us gets sick, we all get sick. She was talking to one of her friends about it, and they said to drink 100% grape juice. They said that doing so is supposed to change the pH levels in your intestinal lining, which keeps the virus from multiplying, which in turn keeps you from getting sick. We tried it, and it worked! No one else got sick that time. My little brother threw up 7 times yesterday, and we all loaded up on grape juice. So far, no one else has gotten sick. It has to be 100% grape juice for it to work, though. I'm not saying it's completely foolproof, but it's worked so far. Hope you guys can use this information.