We examined preserved medical charts of 470 Spanish influenza patients (8 with fatal cases) hospitalized at former army hospitals in Japan during 1919-1920. The following factors were associated with longer periods of hospitalization: adventitious discontinuous lung sounds, maximum respiration rate, continuation of high fever after hospital admission, and diphasic fever.
Keywords: Japan; Spanish influenza; adventitious lung sounds; bacterial pneumonia; disease severity; influenza pandemic; influenza virus; length of hospitalization; pneumonia; respiration rate; respiratory illnesses; respiratory infections; second wave; time course of fever; viral pneumonia; viruses; zoonoses.