Another interesting book about this flu outbreak is called The Great Influenza, by John M. Barry. It also explores the history of the medical sciences in the US, which was lagging behind its European counterparts in the late 19th and early 20th centuries and was involved in a huge game of catch up when the epidemic hit.
I second The Great Influenza. I leaned more about the history of medical science in that book than I had learned with my master's degree in the science of nursing.