[An evaluation of the epidemiological and immunological efficacy of the vaccinal prophylaxis of diphtheria and tetanus].

The extensive use of adsorbed diphtheria-tetanus toxoid with reduced antigen content was found to be ineffective in the prophylaxis of diphtheria: 86.3% of diphtheria patients among those who had been immunized with this preparation fell only a year after the first booster immunization, and the proportion of those who proved to be unprotected against diphtheria on years 3, 4 and 5 after immunization reached, respectively, 21.0%, 35.5% and 49.4%. The number of children immunized with this preparation at common preschool institutions may reach 50% and more, and with an increase in the coverage of children with immunization from 10% to 50% the proportion of unprotected children may rise from 7.4% to 17.8%. The proportion of preschool institutions, insufficiently protected from diphtheria and, as a consequence, running a considerable risk of becoming (in case of the penetration of this infection) the foci of diphtheria, was found to reach 32.9%.