How did the 1918 flu end? How long did it last?

Explanation:

The Spanish flu pandemic of 1918, the deadliest in history, infected an estimated 500 million people worldwide—about one-third of the planet’s population—and killed an estimated 20 million to 50 million victims, including some 675,000 Americans. The 1918 flu was first observed in Europe, the United States and parts of Asia before swiftly spreading around the world. At the time, there were no effective drugs or vaccines to treat this killer flu strain. Citizens were ordered to wear masks, schools, theaters and businesses were shuttered and bodies piled up in makeshift morgues before the virus ended its deadly global march.

By the summer of 1919, the flu pandemic came to an end, as those that were infected either die d or developed immunity. Almost 90 years later, in 2008, researchers announced they’d discovered what made the 1918 flu so dea d ly: A group of three genes enabled the virus to weaken a victim’s bronchial tubes and lungs and clear the way for bacterial pneumonia. Since 1918, there have been several other influenza pandemics, although none as de adly. A flu pandemic from 1957 to 1958 k illed around 2 million people worldwide, including some 70,000 people  in the United States, and a pandemic from 1968 to 1969 kill ed approximately 1 million people, including some 34,000 Americans. More than 12,000 Americans perished during the H1N1 (or “swine flu”) pandemic that occurred from 2009 to 2010.

Explanation:

Ps. I had to put spaces cuz it wouldnt let me use some words

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