This is the question asked yesterday on Uclue, titled Can getting sick be good for you?
This interesting question, apparently, doesn't have a clear-cut answer, but a UClue researcher, davidsarokin does his best to answer it. The answer is very interesting, and apparently, our grandmothers were right.
For more such interesting questions:
Must we wash our hands in the bathroom? (was this question asked by a five year old?)
Is there such a thing as a Real life Dr. House?
Are Chakras Real ?