A laboratory comparison of the potency of United States and British Army TAB vaccines in routine use in Egypt has been made. The investigation was undertaken with the foreknowledge that the British vaccines failed to prevent large epidemics of typhoid and a relatively high overall enteric fever morbidity in the post World War II environment of the Suez Canal Zone.
Current British TAB inoculation routine with both alcoholized and phenolized vaccines conveys to an individual at least three times as much bacterial material, including twice as much of the typhoid component, as does the present American practice.
The British alcoholized vaccine, compared with the equivalent phenolized product, produced significantly greater amounts of “Vi” agglutinin in mice. Very much larger amounts of American vaccine were required to equal the “Vi” agglutinin production of either type of British vaccine.
In a series of mouse protection tests the British alcoholized vaccine proved to be significantly more potent than the equivalent phenolized product. In the same experiments the American vaccine, even allowing for quantitative differences in bacterial content, compared with the British, was surprisingly ineffective.
The significance of these findings is discussed.
Department of Bacteriology, U. S. Naval Medical Research Unit No. 3 Cairo, Egypt.
The opinions or assertions contained herein are the private ones of the writers and are not to be construed as official or reflecting the views of the Navy Department or the naval service at large.