In spring 1920, The fourth wave, occurred in isolated areas including New York, Switzerland and some South American Islands. New York city alone reported 6,374 deaths between December 1919 - April 1920, almost twice the number in first wave in 1918. Other US cities including Detroit, Kansas city, St. Louis and other cities as well were hit particularly hard, with deaths rate higher than of all 1918. Peru experienced the late wave of early 1920, and Japan had one from late 1919 to 1920, with the late cases in March. In Europe five countries ( Spain, Denmark, Finland, Germany and Switzerland.) recorded a late peak of January - April 1920.
