RESUMO
Three types of inactivated bivalent influenza vaccines containing the A/Victoria/3/75 (A-Component) and B/Hongkong/8/73 (B-Component) antigens either as aluminium salt adsorbed whole virus (AlorbatTM, "A") and split virus (Begrivac STM, "B") or as fluid subunit (SandovacTM, "S") products were given to immunological homogeneous study groups of adults and children. The immune response was compared between the groups on the basis of systemic and local neuraminidase inhibiting (NI) antibody induction 4 weeks after vaccination. In evaluation of the serologic results the sea and nasal washings were tested in the ESSEN-NIT with use of the A/Eq(eq1)-VIC (N 2) recombinant antigen and the B/Hong kong/8/73 strain. The number of individuals (adults plus children) evaluated ranged from 33 to 35 per vaccine. The percentages of persons greater than or equal to 16 years old showing a significant (1.5 x, or greater) response to the A-component were 100%, 96% and 90%, respectively for the vaccine "A", "S" and "B"; the values for the B-component were 70%, 79% and 74%, respectively. The observed conversion rates in children ranged 70% to 100%. Local antibody formation was less pronounced, the percentages of significant conversions were scattered over a wide range from 13% to 80% yielding slightly better responses in children than adults. Taken altogether, the results of the trial indicate that the 3 vaccines studied induced appreciable concentrations of systemic antibodies to the neuraminidase antigen without significant differences between the vaccine types. This potency of the influenza vaccines to induce high titers of NI antibodies thus provides another marker for their immunogenicity and conceivably for their efficacy.