[Specific prevention of diphtheria in adults in foci of this infection].

The studies demonstrated the immunological and epidemiological effectiveness of a single injection of adsorbed diphtheria-tetanus toxoid with reduced antigen content for adults: intense antidiphtheria immunity in 92.3% of the vaccinees 1-3 months and in 94.5% of the vaccinees 1 year after the injection. This immunity remained sufficiently intense for 3 years (the term of observation). The geometric mean of antitoxic titers was 0.84 I. U./ml. The highest intensity of immunity appearing after the injection was observed in persons aged 18-20 years who showed the highest antitoxic titers (exceeding 0.5 I. U./ml) in 100% of cases, the lowest intensity was registered in the age group of 30-39 years; in 14.2% of these vaccinees antitoxic titers were below the protective level. In other age groups (40-49 years, 50 years and over) the intensity of immunity was high. The geometric mean of the titers of diphtheria antitoxin were 1.2 I. U./ml and 2.1 I. U./ml respectively. In none of the foci under study the spread of the manifest forms of the disease was observed.