Spanish Flu: Uncovering the 1918 Pandemic
The Spanish flu was the 1918-1920 influenza pandemic caused by an H1N1 influenza A virus. It infected about 500 million people worldwide and killed an estimated 17 to 50 million, with its heaviest toll falling, unusually, on healthy adults between 20 and 40 years old [3][4]. Published: 2026-06-05. Last reviewed: 2026-06-05. What the Spanish Flu […]
Encephalitis Lethargica 1916-1928: The Sleeping-Sickness Pandemic That Vanished Without Cause
Encephalitis lethargica, the so-called sleeping sickness, swept across at least 64 countries between 1916 and 1928, infected an estimated one million people, killed roughly half of them, and then — without an identified pathogen, without an isolated antibody, without a vaccine — receded into clinical rarity by 1930 and never returned at epidemic scale [1][2]. […]