[The duration and strength of postvaccinal measles immunity]. / Dlitel'nost' i napriazhennost' postvaktsinal'nogo protivokorevogo immuniteta.

A prolonged immunoepidemiological follow-up of a large group of children immunized against measles revealed a high epidemiological efficacy of a single vaccination. Cases of measles were registered only among those vaccinees in whose blood sera no specific hemagglutinins were detectable by titration with 4 hemagglutinating units of measles antigen prior to the disease. The study showed that groups of children seronegative with respect to measles appeared, as a rule, after unsatisfactory immunization and not due to loss of postvaccinal immunity with time. Properly immunized children in whom the formation of antimeasles antibodies had occurred in response to the injection of live measles vaccine retained postvaccinal immunity for more that 15 years (the term of observation).

[The duration and intensity of measles immunity after a repeat inoculation against this infection]. / Dlitel'nost' i napriazhennost' immuniteta k kori posle povtornoi privivki protiv étoi infektsii.

Controlled study lasting 6 years showed that booster immunization against measles was highly effective in children remaining seronegative, i. e. susceptible to this infection, after primary immunization: E = 97.5 +/- 0.12% (K = 35.7). Annual serological examination of children given booster immunization revealed that 87.6% of initially seronegative children retained specific antihemagglutinins for 5.5 years (the term of observation). The effectiveness of booster immunization against measles did not depend on the age when primary immunization had been made.

[Reactogenic properties of a DTP vaccine with a reduced antigen dosage]. / Reaktogennye svoistva AKDS-vaktsiny so snizhennoi antigennoi nagruzkoi.

The reactogenic properties of batches of adsorbed DPT vaccine with the normal content of antigens and with the content of diphtheria and tetanus toxoids reduced, respectively, to 10 Lf and 5 BU per immunization dose have been studied under the conditions of a controlled epidemiological trial. The reduced antigenic content of adsorbed DPT vaccine decreased the number of vaccinal reactions 1.8 times, as well as the intensity of their manifestations.

[Immunological effectiveness of a booster inoculation against measles in children remaining seronegative after vaccination]. / Immunologicheskaia éffektivnost' povtornoi privivki protiv kori detei, ostavshikhsia seronegativnymi posle vaktsinatsii.

Booster immunization against measles with a highly immunogenic vaccine leads to the development of prolonged postvaccinal immunity lasting at least 6-7 years (the term of observation) in the groups of children found to be seronegative after the titration of their blood sera with 1 hemagglutinating unit (HAU) of the antigen. The booster immunization of children in whose blood sera the minimal concentrations of antibodies can be determined in the presence of 1 HAU of the antigen (seronegative in the presence of 4 HAU) is less effective. The serological checks of immunized children entering preschool institutions and the primary grades at schools and the subsequent booster immunization of children found to be seronegative will lead to a further decrease in measles morbidity.

[Immunostructure of school-age children inoculated against measles]. / Immunostruktura privitykh protiv kori detei shkol'nogo vozrasta.

The mass serological survey of school children immunized against measles was carried out by means of the hemagglutination inhibition test. As a result, 20.4% of these school children were found to be seronegative, and in 9.5% of them even the minimum concentration of measles antihemagglutinins (when titrated with 1 hemagglutinating unit of the antigen) was not detected. The accumulation of a considerable seronegative (measles-susceptible) stratum among children of school age occurred due to the low immunogenic potency of some batches of live measles vaccine, used for immunization in 1973, as well as due to the formerly practiced immunization of children under 1 year of age. A direct and close dependence of focal measles morbidity among immunized children having had contacts with the source of infection on the number of children among them, found to be seronegative after titration with 1 hemagglutination unit of measles antigen, was established.

[Method of detecting persons needing reinoculations against measles]. / Metodika vyiavleniia lits, nuzhdaiushchikhsia v povtornykh privivkakh protiv kori.

The epidemiological analysis of 118 measles foci and the total morbidity rate in measles in the populated locality has been carried out. The admissible focal and morbidity levels in measles among vaccinated children have been established. The method of selecting groups in need of the repeated immunization against measles has been proposed. The authors state that only serological control in the hemagglutination inhibition test with the use of 1 hemagglutinating unit of the antigen can detect measles-susceptible groups.

[Antigenic similarity of the pertussis component of adsorbed DTP vaccine to human erythrocytes]. / Antigennaia obshchost' kokliushnogo komponenta AKDS-vaktsiny s éritrotsitami cheloveka.

The similarity of the heterogeneous antigens, types A and B, of human red blood cells to the most of B. pertussis strains constituting the pertussis component of commercial batches of adsorbed DPT vaccine has been established. This property makes the vaccine strains different from B. pertussis isolated from pertussis patients. One of the reasons of the insufficient effectiveness of immunization against pertussis has been determined: the intensity of immune response depends on the antigenic heterogeneity of the pertussis component of the vaccine and the AB0 group factors in the blood of the vaccinees. For the first time the accumulation of immune alpha- and beta-isoagglutinins in the blood of persons immunized with absorbed DPT vaccine has been established. This accumulation shows the medium degree of direct correlation with the manifestations of the clinical reaction to the injection of the vaccine. The data obtained in this study indicate the necessity to revise the existing method of obtaining the pertussis component of adsorbed DPT vaccine on solid culture media with human red blood cells added and to develop the technique of the additional purification of this component from heterogeneous antigens.

[Effect of duration of the intervals between immunization with DPT vaccine on the serological indices in children]. / Vliianie prodolzhitel'nosti intervalov mezhdu privivkami AKDS-vaktsiny na serologischeskie pokazateli u detei.

The influence of the interval between injections of adsorbed DPT vaccine on the effectiveness of immunization has been studied. The intensity of antibody formation to the pertussis component has been found to decrease 2.7-3.7 times if the interval between the injections constituting the course of primary immunization is prolonged for more than 6 months. The interval between the course of primary immunization and the first booster injection, which lasts 1.5-2 years in accordance with the currently accepted immunization schedule, is unreasonably long. Immunological characteristics in respect to pertussis have been found to decrease 8-45 times as early as 16 months after the first booster injection. Most of the vaccines catching pertussis at that time had the moderately severe form of this infection.

[Results of a study of the reactogenicity and epidemiological effectiveness of a 2d revaccination against whooping cough]. / Rezul'taty izucheniia reaktogennosti i épidemiologicheskoi éffektivnosti II revaktsinatsii protiv kokliusha.

The reactogenicity and epidemiological effectiveness of the second revaccination against pertussis were studied in conformity with all the conditions of a controlled epidemiological trial. The character of the distribution of local and fever reactions in children aged 6 years after the second revaccination with adsorbed DTP vaccine suggests the presence of high sensitivity to the pertussis component of absorbed DTP vaccine in children of this age group. The results obtained from the study of epidemiological effectiveness (in 15,621 children) indicated that the second revaccination of children aged 6 years (at an interval of 3 or more years after the first revaccination) was not advisable as it did not influence noticeably the pertussis incidence.

[Effectiveness of revaccination against measles]. / Ob éffektivnosti revaktsinatsii protiv kori.

The authors studied the efficacy of measles revaccination in children in whose serum no specific antihemagglutinins were revealed in titration with 1 GAE antigen (the first group) and having no specific antibodies in titration with 4 GAE antigen (the second group). Investigations demonstrated that children in whose blood serum no measles antibodies were revealed in the presence of 1 GAE antigen were subject of vaccination. Repeated vaccination used at present in persons who produced minimal antibody concentrations in response to vaccination is not recommended.

[An epidemiologic and immunologic study of measles under conditions of massive immunization against that infection]. / Epidemiologicheskoe i immunologicheskoe izuchenie kori v usloviiakh massovoi immunizatsii protiv étoi infektsii

Massive measles immunization in Riga led to a marked reduction of measles incidence and to a change of the principal regularities of the epidemic process in this infection. Among those who contracted the disease there was an increase in the percentage of schoolchildren; affection with measles of children attending creches and kindergartens and the intensity of the spread of the infection in them diminished. Selective examination of the immunological efficacy of the living measles vaccine prepared of the (see article) and applied in 1967--1972 demonstrated the presence of specific stimulation of the antibody formation in about 90% of the persons vaccinated. The intensity of humoral immunity in the persons vaccinated did not diminish with the advance of time after the vaccination, and 6--7 years after the vaccination over 90% of the vaccinated individuals were reliably protected from measles. The presence of numerous negative results in carrying out the vaccinations in individual institutions is apparently attributed chiefly to disturbances of the storage regimen of transportation and of the use of the vaccine.