Wow! I'm in the dark ages or something. I've never seen one person (including myself with chronic bronchitis) ever be prescribed Prednisone for a common cold, flu, or anything except COPD (think more on the emphysema side). I know my mother was prescribed Prednisone for that reason. I've ran across others that take it...but all for COPD.
As someone else posted, it can be used for other conditions. Specifically for someone with an autoimmune disorder since it suppresses the immune system. It also helps in reducing inflammation.