title: Vaccination-induced HI antibody response to intraepidemic influenza A(H3N2) virus variants of the 1996-1997 epidemic season.
abstract: Intraepidemic antigenic and genetic variation was indicated when H3N2-subtype influenza A virus strains isolated during the 1996-1997 epidemic season in Finland were studied for reactivity in the haemagglutination inhibition (HI) assay and for nucleotide sequences coding for the variable HA1 domain of viral haemagglutinin. Thirty prevaccination- and postvaccination-paired sera taken from subjects who had been vaccinated against influenza during the previous autumn were studied for the presence of HI antibody to the homologous vaccine virus A/Nanchang/933/95, and five field strains representing the genetic and antigenic variability of the 1996-1997 epidemic season. The lowest vaccination-induced HI titres in each of the three age groups were detected in the two field strains that had been isolated from vaccinated patients and belonged to two different genetic sublineages. The intraepidemic variability of the 1996-1997 field strains in HI reactivity may be indicative of circulation of virus strains that may be capable of breaking through vaccination-induced immunity better than the other strains.
authors.affiliation: National Public Health Institute, Mannerheimintie 166, 00300 Helsinki, Finland. reijo.pyhala@ktl.fi
authors.forename: R
authors.initials: R
authors.lastname: Pyhälä
authors.forename: N
authors.initials: N
authors.lastname: Ikonen
authors.forename: R
authors.initials: R
authors.lastname: Santanen
authors.forename: M
authors.initials: M
authors.lastname: Haanpää
authors.forename: R
authors.initials: R
authors.lastname: Visakorpi
authors.forename: P
authors.initials: P
authors.lastname: Jäppinen
authors.forename: M
authors.initials: M
authors.lastname: Valle
mesh_terms: D000328:Adult; D000368:Aged; D000914:Antibodies, Viral / Q000097:blood*; D004196:Disease Outbreaks; D005260:Female; D006385:Hemagglutination Inhibition Tests; D019267:Hemagglutinin Glycoproteins, Influenza Virus / Q000235:genetics / Q000276:immunology*; D006801:Humans; D053122:Influenza A Virus, H3N2 Subtype; D009980:Influenza A virus / Q000145:classification / Q000235:genetics / Q000276:immunology*; D007252:Influenza Vaccines / Q000276:immunology*; D007251:Influenza, Human / Q000453:epidemiology* / Q000276:immunology / Q000517:prevention & control / Q000821:virology; D008297:Male; D008875:Middle Aged; D017720:Molecular Epidemiology; D008969:Molecular Sequence Data; D014611:Vaccination
chemical_list: D000914:Antibodies, Viral; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D007252:Influenza Vaccines