<Tr> <Td> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> </Td> </Tr> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> <P> The 1918 flu pandemic (January 1918--December 1920) was an unusually deadly influenza pandemic, the first of the two pandemics involving H1N1 influenza virus . It infected 500 million people around the world, 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), making it one of the deadliest natural disasters in human history . </P> <P> 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 . Most influenza outbreaks disproportionately kill juvenile, elderly, or already weakened patients; in contrast, the 1918 pandemic predominantly killed previously healthy young adults . </P>

Flu that spread over a large area in 1918