Different strains of influenza produce different symptoms and side effects. The primary types of the flu virus are A, B, and C. Type A flu viruses are the worst of the lot and cause the most harm; they are capable of mutating and defeating the current vaccines. H1N1 or swine Flu is a type A flu virus. Type B flu, a weaker strain of influenza, mainly affect children and the elderly. Type C flu viruses are common, and symptoms are comparable to the common cold.

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