The Antibody Response to Injection with Typhoid Vaccine.

Abstract

Incidental to the investigation of another problem opportunity was afforded to check the results reported in a previous study upon the significance of the antibodies produced by typhoid vaccine., , Forty five students were injected with typhoid vaccine. Agglutination reactions were performed before the injection, and again 10 days after the third dose of vaccine. The results were analysed in the same manner as in the previous study. It was quite upsetting to note that in this case those who had not had previous vaccine responded by a marked agglutinin production (1/300) instead of a low average (1/66) as before, completely reversing one of the conclusions drawn in the former work. On the other hand, those who had had typhoid fever responded in about the same manner this time (1/288) as before (1/285). Likewise those who had had previous typhoid vaccine produced agglutinins in comparable titers in this series (1/113) as in the previous group (1/162). It is interesting to note, however, that when the 2 groups are combined, so that we have a total of 135 individuals instead of 45, the averages again return to the relation found in the first experiment, those who had had typhoid fever averaging 1/287, those who had had previous typhoid vaccine 1/143, and those who had had neither 1/115. The reversal of the average in the one group in the second experiment was produced by the high agglutinin titers of 4 students. There were individuals with just as high titers in the previous study, but chance happened to throw 4 such students into a small group of 9 in the latter instance and there were only 4 with titers as high in a group of 34 in the first experiment.