Occurring in 1918 it is regarded as the deadliest in history. An estimated 500 million people were infected – about a third of the world’s population – and about 50 million people died globally.
The flu outbreak began in Europe, the United States, and parts of Asia before swiftly spreading around the world reaching pandemic status. At the time, there were no effective drugs to treat patients or vaccines to prevent transmission of the virus. Citizens were ordered to wear masks, and schools, theatres, and businesses were shut down as bodies piled up in makeshift morgues. By the summer of 1919, the Spanish flu pandemic came to an end, as those that were infected either died or developed immunity.