[The duration and strength of postvaccinal measles immunity].

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.

[The duration and intensity of measles immunity after a repeat inoculation against this infection].

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.

[Reactogenic properties of a DTP vaccine with a reduced antigen dosage].

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].

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].

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.

[Method of detecting persons needing reinoculations against measles].

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.

[Antigenic similarity of the pertussis component of adsorbed DTP vaccine to human erythrocytes].

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.

[Effect of duration of the intervals between immunization with DPT vaccine on the serological indices in children].

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.

[Results of a study of the reactogenicity and epidemiological effectiveness of a 2d revaccination against whooping cough].

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].

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].

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.