Approximately 50 million people died after being infected with the Spanish flu during the 1918 pandemic. The high infection and mortality rate among young people was one of the perplexing mysteries of the 1918 influenza pandemic. Older adults are generally the most vulnerable during infectious disease outbreaks, but they have largely been unaffected by the Spanish flu virus. A recent reconstruction of the chronology of dominant influenza strains dating back to the 19th century offered a possible explanation for the severity of the 1918 influenza pandemic, particularly in young people. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an Original Essay Flu strains can be identified by proteins on the surface of the flu virus that allows it to enter and exit cells in your body. These proteins are hemagglutinin and neuraminidase. Hemagglutinin acts as a key to open the doors of the cell and allows the virus to enter the cell and begin using the cellular machinery to replicate. Then neuraminidase is used to open the door from the inside and allow the replicated virus to leave the cell and infect other cells in the body. There are 16 subtypes of hemagglutinin and 9 subtypes of neuraminidase. Different combinations of these subtypes represent all the different strains of influenza, and each of these subtypes has a number of different antigenic variants, leading to possible thousands of possible strains. Using preserved tissue samples, scientists have constructed the genomes of the dominant influenza strains of the 19th and 20th centuries. Starting with the H1N1 subtype in 1830, N8 is believed to have entered the genome, and from 1847 to 1889 the dominant subtype was the H1N8 subtype. H3 entered the genome around 1889, and the H3N8 strain remained dominant for the next twelve years. H1 returned, and the H1N8 subtype was dominant from 1900 to 1918, when N1 returned to the fold. A new strain of H1N1 was responsible for the 1918 pandemic. Following this time frame, the H1N1 subtype dominant from 1830 to 1847 would have exposed people to a strain of influenza similar to the strain of H1N1 responsible for the influenza pandemic in 1918. The H1 subtype was also present in the dominant subtype from 1847 to 1889. Those born between 1830 and 1847, who would have been between 71 and 88 years old in 1918 would have been inoculated with the similar strain to which they had been exposed as children and young adults. Scientists speculate that this is why the elderly were mostly immune to the H1N1 strain that caused the pandemic in 1918. On the other hand, young people were ravaged by the flu in 1918. Looking at the timeline of the dominant flu strains, between 1889 and 1900, the dominant influenza subtype was H3N8, which does not include any of the subtypes of the H1N1 subtype that caused the pandemic in 1918. The unfamiliarity of the immune system of those born in those years with the H1N1 subtype is hypothesized by scientists as why the 20- to 40-year-old age group suffered disproportionately high mortality rates during the 1918 pandemic. Those born between 1889 and 1900, when the H3N8 subtype was dominant, fall almost directly into that category of age in 1918. Another reason young people with robust immune systems have been hit so hard is that scientists identified the 1918 flu strain as causing a cytokine storm, where the infected person's immune system goes into overdrive. overdrive, causing a cascade of overabundance of inflammatory factors that overwhelm the body and lead to death. To further exacerbate the,.