Nature of the antibodies in persons inoculated with a leptospirosis vaccine

: The results obtained in the study of the intensity and character of immunity in persons immunized with commercial leptospirosis vaccine are presented. These results indicate that antibody formation occurs only in 12.5% of the vaccinees; antibodies are not formed to all Leptospira strains contained in the vaccine, and in 6 months all antibodies completely disappear. In persons immunized with a single vaccine dose the agglutinating activity of blood sera was linked only with IgM. In persons subjected to multiple immunizations for a number of years IgG could also be detected. Cases of leptospirosis among vaccinees have been registered.