FIELD and laboratory studies with typhoid vaccines: a preliminary report: Yugoslav Typhoid Commission.

In 1953 the Yugoslav Typhoid Commission organized the first strictly controlled field trial of two types of anti-typhoid vaccine-alcoholized and phenolized-in an attempt to determine the relative and absolute effectiveness of each. They were tested against a phenolized control vaccine prepared from strains of Shigella flexneri, type II.This preliminary report gives the basic information on the conditions of the trial, in which 35 508 persons completed the course of two injections, and shows the results obtained.The phenolized vaccine proved the more effective of the two, giving protection in about 70% of the vaccinated, but the Commission points out that the results do not necessarily mean that the same degree of protection would be obtained with other batches of either vaccine. Laboratory work done with the field trial showed that the existing laboratory tests cannot at present be correlated with the protection afforded to man.