U.S. American Red Cross Naval Hospital, Bordeaux, France, Group of patients. The most important volunteer group in America during WWI was the American Red Cross. During WWI more than eighteen thousand Red Cross nurses served with the Army and Navy Nurse Corps. Some of these nurses worked at American base hospitals, at field units, and aboard ships, whereas others, served at home combating the 1918 influenza epidemic and providing medical services to military camps, munitions plants, and shipyards. They also helped to recruit and train ambulance drivers and orderlies at various universities. By the time the war ended in November 1918, the Red Cross had become a major national humanitarian organization.