No abstract

Influenza vaccination in HD patients is as effective as the vaccination of cardiac patients with normal kidney function. The cross-reactivity of vaccination-induced antibodies is even as good as that of antibodies induced by natural infection of young healthy males. Additionally, vaccination seems to prime the individual beneficially against subsequent years' influenza viruses.

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.

In September 2009, an outbreak of 2009 pandemic influenza A(H1N1) took place in a Finnish garrison. In November 2009, we performed a serological survey among 984 recruits undergoing their military service at the garrison and related the results to self-reported upper respiratory tract infection (URTI) with or without fever. Of 346 volunteers who donated a blood sample, 169 (49%) had pandemic influenza A(H1N1) virus-specific antibodies. Of those, 84 (50%) reported no recent history of URTI, suggesting that a major part of those infected with pandemic influenza A(H1N1) virus may be asymptomatic.

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.