[Field trials with an oral cell-free vaccine made from Shigella flexneri].

The data on the study of the reactogenicity, safety and prophylactic potency of a new acellular vaccine prepared from S. flexneri 2a antigenic complexes are presented. According to the results of two epidemic experiments, the vaccine, introduced by oral administration, showed low reactogenicity, safety and sufficient prophylactic potency. The vaccine decreased morbidity rate in dysentery caused by S. flexneri 2a and ensured the protection of 74% (72-80%) of the vaccinees. The complete course of immunization consisting of three administrations followed by the booster administration induces the formation of specific immunity whose duration is sufficient for ensuring the protection of immunized persons during the epidemiologically unfavorable period (for at least 3 months).