In 2012, scientists were able to genetically sequence the 1918 virus, confirming that the influenza pandemics of 1957, 1968, and 2009 were direct descendants of the 1918 virus. In fact, because scientists were able to understand the structural similarities of the 2009 virus versus the 1918 virus, they were able to pinpoint what age groups would be most vunerable to infection by the 2009 influenza virus. This allowed them to concentrate the vaccine to those who truly needed the supplies—in this case, to younger people.
This photo was taken in a Camp Funston, Kansas, ward during the 1918 Spanish flu epidemic. Fifty million people died during that horrible outbreak.