We need to understand first what is influenza or also known as flu, and it is described as infection caused by virus. It is very contagious and affects the upper airways and lungs. Each year the common flu kills approximately 30,000 Americans each year as stated in the news this year. We now question what makes flu different than the H1N1 flu? H1N1 is a flu which is a subtype and the virus responsible to cause is influenza A virus subtype H1N1. This H1N1 which is commonly described as swine influenza also called as swine flu, hog flu, pig flu and so the list continues. H1N1 is Swine influenza virus (SIV) and the strains include influenza C and the subtype of influenza A is known as H1N1, H1N2, H3N1, H3N2, and H2N3.