Comparison of US inactivated split-virus and Russian live attenuated, cold-adapted trivalent influenza vaccines in Russian schoolchildren.

In a blinded, placebo-controlled study, the reactogenicity, immunogenicity, and clinical efficacy of single doses of US inactivated split-virus and Russian live attenuated, cold-adapted influenza vaccines were compared in 555 schoolchildren in Vologda, Russia. Serial serum samples were collected and school absenteeism was assessed. Systemic reactions were rare, but local reactions (primarily erythema at the injection site) were observed in 27% of the inactivated vaccine group, and coryza (12%) and sore throat (8%) were observed in the attenuated vaccine group.

Class-specific antibody responses in school children vaccinated with an A/Brazil/11/78 (H1N1)-like recombinant influenza virus prepared from the A/Leningrad/134/57 paediatric cold-adapted donor strain.

Forty-three school children from 8 to 11 years old were vaccinated intranasally with two doses of a paediatric attenuated influenza vaccine developed by reassortment between cold-adapted A/Leningrad/134/57(H2N2) and an A/Brazil/11/78(H1N1)-like strain. Two vaccine doses were administered 1 month apart in a randomized, blind, placebo-controlled study. Although the first vaccine dose had a low infectivity titre, overall 65% of children who received two doses of vaccine showed serological evidence of infection by HI tests.

Interfering activity of epidemic, attenuated and recombinant strains of influenza A virus.

Interfering activity (IA) of the epidemic and attenuated influenza virus strains of different ts-phenotype was studied. IA was assessed by inhibition of vaccinia virus cytopathic effect in chick embryo chorioallantoic membrane (CAM) cells. Direct relationship was established between the temperature sensitivity (ts) index and IA of these viruses.