ABSTRACT
The study of the based on the A/Leningrad/134/17/57/(H2N2) attenuated adult live influenza vaccine (LIV) investigated features for immunization of the children, aged 3-6 years. During autumn, 1999, out of 256 children, aged 3-6 years, residents of the Leningrad region, who attended the kindergarten, 184 children were immunized with 1 or 2 doses of the live influenza vaccine, and 72 ones were given placebo. There were no any moderate or strong temperature reactions revealed after the inoculation. The LIV was shown to be genetically stable. After a single dose of the vaccine seroconversion to influenza type A virus and to influenza type B virus was observed respectively in 58% and in 39% of seronegative 3-6 year old vaccinees. The twofold LIV administration failed to give any advantages in stimulation of the immune response. During 6 months after immunization the morbidity rate in vaccinees did not exceed the morbidity rate in unvaccinated children. Thus LIV for adults proved safe and immunogenic and can be recommended for single dose immunization both of adults and children.
Subject(s)
Influenza, Human/prevention & control , Orthomyxoviridae/immunology , Vaccination , Viral Vaccines/administration & dosage , Administration, Intranasal , Antibodies, Viral/blood , Child , Child, Preschool , Fever/pathology , Humans , Immunization Schedule , Influenza, Human/blood , Orthomyxoviridae/genetics , RNA, Viral/analysis , Restriction Mapping , Russia , Urban Population , Vaccines, Attenuated/administration & dosage , Vaccines, Attenuated/genetics , Vaccines, Attenuated/immunology , Viral Vaccines/genetics , Viral Vaccines/immunologyABSTRACT
In Russia for prevention of influenza in children, aged from 3 to 14 years, the children's live influenza vaccine (LIV), based upon A/Leningrad/134/47/57(H2N2) master strain (LIVI) is used. The need for double immunization appears to be one out of the faulties of this preparation. The study was aimed to comparing the safety, immunogenic activity and prevention of influenza by LIV for adults (LIVII) (A/Leningrad/134/17/57(H2N2 master strain) and LIVI in children aged from 7 to 17 years under similar administration schedule. The safety, the preventive efficacy, humoral and secretory immunity were studied. In total 2486 persons, including 539 children, twice inoculated with LIVI, 971 persons once inoculated with LIVII, and 840 treated by placebo were obserbed. From the data of the clinical observations during 7 days after immunization both vaccines appeared to be low reactogenic. The LIVII advantages in induction of the humoral and secretory antibodies in comparison with children's vaccine had been revealed. Both vaccines were highly efficacious, the efficiency of both preparations was more pronounced after serologic correction of the diagnosis. The results obtained permit to recommend the single immunization by the variant of LIV at the base on A/Leningrad/134/17/57/(H2N2) master strain for prevention of influenza in school children.
