The Protective Effect of Various Typhus Fever Vaccines in Man and the Course of the Disease Following Immunization

The tolerance and effect of various vaccines were tested among two large groups infected with typhus fever, the material being obtained from louse intestines, egg yolk cultures, rabbit and canine lungs. The following results were obtained 1 The incubation time of typhus fever may be considerably shorter than heretofore assumed. By inoculation, fever was depressed, the duration of the fever was shortened, and the entire course was considerably alleviated with respect to the central nervous system and the circulation. 2 The immunization protects against death in the overwhelming majority of cases. It does not seem to decrease morbidity. 3 The newer vaccines from egg yolk sac cultures, rabbit and canine lungs are suitable in typhus fever. 4 Even vaccines with mixtures of strains of R. mooseri and prowazeki considerably attenuate the course of typhus fever. 5 The white blood picture was carefully observed in all groups. It shows a strong increase in staff cells. A difference between immunized and non-immunized typhus fever patients cannot be deduced from the blood picture.