The 1918 influenza pandemic (January 1918 – December 1920; colloquially known as: Spanish flu) was an unusually deadly influenza pandemic, the first of the two pandemics involving H1N1 influenza virus.[1]
It infected 500 million people around the world,[2] including people on remote Pacific islands and in the Arctic, and resulted in the deaths of 50 to 100 million (three to five percent of the world's population),[3] making it one of the deadliest natural disasters in human history.[4][5][6]
Disease had already greatly limited life expectancy in the early 20th century. In the first year of the pandemic, life expectancy in the United States dropped by about 12 years.[7][8][9] Most influenza outbreaks disproportionately kill juvenile, elderly, or already weakened patients; in contrast, the 1918 pandemic predominantly killed previously healthy young adults.[10]
The 1918 influenza pandemic (January 1918 – December 1920; colloquially known as: Spanish flu) was an unusually deadly influenza pandemic, the first of the two pandemics involving H1N1 influenza virus.[1] It infected 500 million people around the w