The horrific scale of the 1918 influenza pandemic—known as the “Spanish flu”—is hard to fathom. The virus infected 500 million people worldwide and killed an estimated 20 million to 50 million victims— that’s more than all of the soldiers and civilians killed during World War I combined.
While the global pandemic lasted for two years, the vast majority of deaths were packed into three especially cruel months in the fall of 1918. Historians now believe that the fatal severity of the Spanish flu’s “second wave” was caused by a mutated virus spread by wartime troop movements.
Somewhere in Europe, a mutated strain of the Spanish flu virus had emerged that had the power to kill a perfectly healthy young man or woman within 24 hours of showing the first signs of infection.
In late August 1918, military ships departed the English port city of Plymouth carrying troops unknowingly infected with this new, far deadlier strain of Spanish flu. As these ships arrived in cities like Brest in France, Boston in the United States and Freetown in west Africa, the second wave of the global pandemic began.