tetano
Editor, Senior Moderator
Adv Exp Med Biol. 2015 Nov 18. [Epub ahead of print]
[h=1]Partial Protection Induced by 2011-2012 Influenza Vaccine Against Serologically Evidenced A(H3N2) Influenza Virus Infections in Elderly Institutionalized People.[/h] Camilloni B[SUP]1[/SUP], Basileo M[SUP]1[/SUP], Menculini G[SUP]2[/SUP], Tozzi P[SUP]3[/SUP], Iorio AM[SUP]4[/SUP].
[h=3]Author information[/h]
[h=3]Abstract[/h] Ninety-two institutionalized elderly subjects were vaccinated with trivalent influenza inactivated vaccine available for the 2011-2012 season, characterized by a prevalent circulation of A(H3N2) influenza viruses (A/Victoria/208-clade) presenting antigenic and genetic patterns different from the A(H3N2) vaccine component (A/Perth/16/2009-clade). Haemagglutination inhibiting (HI) antibody titers were determined in sera collected before, 1 and 6 months after vaccination and patients were considered positive for serological evidence of recent infection if they had a seroconversion on comparing HI titers found in sera collected 1 and 6 months after vaccination. No seroconversions were found against A(H1N1) and B vaccine components. Instead 17 volunteers seroconverted against all or at least some of the different A(H3N2) antigens examined, i.e. the 2011-2012 (A/Perth/16/2009) and the 2012-2013 (A/Victoria/361/2011) vaccine strains and four drifted viruses belonging to the A/Victoria/208-clade circulating in the area were the elderly people were living. The results obtained suggest that influenza infections in the vaccinated volunteers might be due both to a poor match between vaccine and circulating A(H3N2) viruses, since 1 month after vaccination 15 of the 17 volunteers had post-vaccination HI titers considered protective (≥40) against the A(H3N2) vaccine antigen, but not always against the epidemic strains, and to a waning of vaccine induced immune response, since 6 months after vaccination HI titers of non-infected volunteers were found to be decreased as compared with those found 1 month after vaccination.
[h=4]KEYWORDS:[/h] Antigenic drift; Influenza virus; Protection; Vaccination
PMID: 26577530 [PubMed - as supplied by publisher]
[h=1]Partial Protection Induced by 2011-2012 Influenza Vaccine Against Serologically Evidenced A(H3N2) Influenza Virus Infections in Elderly Institutionalized People.[/h] Camilloni B[SUP]1[/SUP], Basileo M[SUP]1[/SUP], Menculini G[SUP]2[/SUP], Tozzi P[SUP]3[/SUP], Iorio AM[SUP]4[/SUP].
[h=3]Author information[/h]
[h=3]Abstract[/h] Ninety-two institutionalized elderly subjects were vaccinated with trivalent influenza inactivated vaccine available for the 2011-2012 season, characterized by a prevalent circulation of A(H3N2) influenza viruses (A/Victoria/208-clade) presenting antigenic and genetic patterns different from the A(H3N2) vaccine component (A/Perth/16/2009-clade). Haemagglutination inhibiting (HI) antibody titers were determined in sera collected before, 1 and 6 months after vaccination and patients were considered positive for serological evidence of recent infection if they had a seroconversion on comparing HI titers found in sera collected 1 and 6 months after vaccination. No seroconversions were found against A(H1N1) and B vaccine components. Instead 17 volunteers seroconverted against all or at least some of the different A(H3N2) antigens examined, i.e. the 2011-2012 (A/Perth/16/2009) and the 2012-2013 (A/Victoria/361/2011) vaccine strains and four drifted viruses belonging to the A/Victoria/208-clade circulating in the area were the elderly people were living. The results obtained suggest that influenza infections in the vaccinated volunteers might be due both to a poor match between vaccine and circulating A(H3N2) viruses, since 1 month after vaccination 15 of the 17 volunteers had post-vaccination HI titers considered protective (≥40) against the A(H3N2) vaccine antigen, but not always against the epidemic strains, and to a waning of vaccine induced immune response, since 6 months after vaccination HI titers of non-infected volunteers were found to be decreased as compared with those found 1 month after vaccination.
[h=4]KEYWORDS:[/h] Antigenic drift; Influenza virus; Protection; Vaccination
PMID: 26577530 [PubMed - as supplied by publisher]