The Spanish flu's mortality isn't that mysterious today (samples have been extracted from victims buried in cold climates, and its genome sequenced). It turns o

The Spanish flu's mortality isn't that mysterious today (samples have been extracted from victims buried in cold climates, and its genome sequenced). It turns out that in young, healthy victims it provokes a cytokine storm -- an overreaction by the immune system that causes a massive inflammatory response and fluid build-up in the lungs (with potential for secondary bacterial infection). Ironically, older or younger victims with weaker immune systems were less likely to succumb to this reaction: More here: https://www.scripps.edu/news/press/2014/20140227oldstonerosen.html https://www.scripps.edu/news/press/2014/20140227oldstonerose...