"The first pandemic wave, which was benign and caused few deaths, took place in the spring of 1918. After a period of calm at the beginning of the summer of 1918, the virus mutated, becoming extremely virulent, and simultaneously caused millions of deaths throughout the world during the following months of October and November. A milder third wave occurred during the initial months of 1919, while the fourth and final wave spread during the first months of 1920."
And yes, it went to South America. Mortality rate was ~1%.