Doctors have finally figured out a guaranteed way to keep you from getting a COLD. And what is this miracle remedy? It's easy: You just need to get the FLU. According to a study of more than 44,000 patients in Scotland, believe it or not, you can't get a cold and the flu at the same time.
Those viruses both create an inflammatory response in your body that basically acts like a barrier to the other one, so the one that gets there first wins out. Unfortunately, they don't block OTHER illnesses from getting through. One example: The flu actually makes you more susceptible to pneumonia.
(CNN)