The Immunization of Troops with Typhus Vaccine and the Characteristics of Typhus in Immunized Individuals *

The entry of the United States into World War II, with exposure of Army troops to epidemic (louse-borne) typhus fever in many parts of the world, called for the use of adequate protective measures against this disease. One important aspect of this protection was the compulsory immunization with epidemic typhus vaccine of all soldiers going to, or stationed in, areas where epidemic typhus was present or suspected. The excellent protection afforded U. S. Army personnel by this prophylactic immunization has already been reported by Sadusk.20 Similar information, including the incidence of typhus fever in the U. S. Army during the war years ( 1942-46 inclusive), notes on the severity of the disease and modification of the clinical course in a limited number of cases, and remarks on the serological diagnosis of typhus in patients who have been inoculated with vaccine prior to onset of the disease, are presented here.