[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.