“Since 1700, there have been approximately a dozen influenza A virus pandemics; in the past 120 years there were pandemics in 1889, 1918, 1957 and 1968” (6). The pandemic in 1918 was the worst in in recorded history which caused approximately 546,000 deaths (6). These are all reasons why the flu is worth studying and finding a vaccine for. There are multiple types of the flu virus, specifically influenza A, B, C, and D. These names are given based on the antigen they have, or antigenic type (2). “Human influenza A and B viruses cause seasonal epidemics of disease almost every winter in the United States” (2). “The emergence of a new and very different influenza A virus to infect people can cause an influenza pandemic” (2). ‘Influenza type C
