2. “Spanish flu”, as the 1918 influenza pandemic became to be known, killed almost five percent of the world in the aftermath of the First World War
The 1918 influenza pandemic, colloquially known as “Spanish flu”, remains among the deadliest natural disasters in human history. Due to wartime censorship in Allied nations, neutral Spain, not being involved placed no such restrictions on the press, and the accurate reporting of outbreaks in the Iberian nation led people to incorrectly associate the illness with Spain. An atypically deadly flu pandemic involving the H1N1 strain of the virus, modern transportation, the close quarters of soldiers during World War I, the weakened condition of many of these soldiers, and the fast movement of troops, helped spread the virus as far away as the Pacific Islands and the Arctic.
A precise explanation for the high mortality rate is uncertain, with flu traditionally claiming the young or old; in contrast, Spanish flu predominantly killed healthy young adults. Infecting an estimated five hundred million people worldwide, approximately one-third of humanity, within the first year of the pandemic life expectancy in the United States dropped twelve years. Carrying a mortality rate of between ten and twenty percent, it is estimated the pandemic was responsible for the deaths of between fifty and one hundred million people, representing three to five percent of the global population, including as many as twenty-five million in the first six months.