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.

Results of a two-year study of humoral immunity to influenza A and B viruses in children under the age of 14 years in Moscow and its suburbs.

A serological survey of antibodies to influenza A(H1N1), A(H2N2), A(H3N2) and B viruses was done with sera collected in Moscow in October 1980 and November 1981 from 542 children under 14 years of age. The results of the study showed convincingly that influenza A(H2N2) viruses were not circulating in Moscow in 1980-81. Low titres found in the sera from four young children were due to cross-reactions which were eliminated from the sera by absorption with A/USSR/174/79(H3N2) virus.