Why do you suppose the 1918 A-H1N1 “Spanish Flu” pandemic isn't given more prominence in our school history texts?

According to source documents and subsequent analyses, this pandemic killed up to 100 million people worldwide, killed more Americans than all our wars combined up to this day, radically changed the way our public health service approaches epidemics, and expedited the developments of virology and epidemiology. Why is it barely mentioned in our history texts, if mentioned at all?