The 1918 flu pandemic was unusually deadly and the first of two involving the H1N1 influenza virus.
It infected 500 million people globally, more than one-third of the world’s population, including people on remote Pacific islands and in the Arctic.
It resulted in the deaths of an estimated three to five per cent of the world’s population, making it one of the deadliest natural disasters in human history.
Spanish Flu resulted in the deaths of an estimated three to five per cent of the world’s population, making it one of the deadliest natural disasters in human history. This image shows soldiers from Fort Riley, Kansas, ill with the virus
Within months it had killed three times as many as World War I and did it more quickly than any other illness in recorded history.
Most influenza outbreaks disproportionately kill juvenile, elderly, or already weakened patients.
By contrast, the 1918 pandemic predominantly killed previously healthy young adults.
To maintain morale, wartime censors minimised early reports of illness and mortality in Germany, Britain, France, and the United States.
However, newspapers were free to report the epidemic’s effects in Spain.
This created a false impression of Spain as being especially hard hit, leading to the pandemic’s nickname Spanish flu.
The close quarters and massive troop movements of World War I hastened the pandemic and probably both increased transmission and augmented mutation, researchers believe.
The true global mortality rate from the pandemic is not known, but an estimated 10 per cent to 20 per cent of those who were infected died.
This would lead to a death toll of between 50 to 100 million people.