tetano
Editor, Senior Moderator
Clin Infect Dis. 2016 Feb 21. pii: ciw085. [Epub ahead of print]
[h=1]Effect of previous year vaccination on the efficacy, immunogenicity, and safety of high-dose inactivated influenza vaccine in older adults.[/h] DiazGranados CA[SUP]1[/SUP], Dunning AJ[SUP]1[/SUP], Robertson CA[SUP]1[/SUP], Talbot HK[SUP]2[/SUP], Landolfi V[SUP]1[/SUP], Greenberg DP[SUP]3[/SUP].
[h=3]Author information[/h]
[h=3]Abstract[/h] [h=4]BACKGROUND:[/h] high-dose inactivated influenza vaccine (IIV-HD) is an alternative to the standard-dose inactivated influenza vaccine (IIV-SD) in the US for influenza prevention in older adults. IIV-HD improved efficacy relative to IIV-SD in a randomized controlled trial. Recent observational studies suggest that previous influenza vaccination may influence the immunogenicity and effectiveness of current-season vaccination.
[h=4]METHODS:[/h] the original study was a double-blind, randomized trial comparing IIV-HD to IIV-SD in adults ≥65 years over two influenza seasons. A subset of year 1 (Y1) participants re-enrolled in year 2 (Y2), receiving vaccine by random assignment in both years. We evaluated the effect of Y1 vaccination on Y2 relative vaccine efficacy (VE), immunogenicity (hemagglutination inhibition [HAI] titers), and safety among re-enrolled participants.
[h=4]RESULTS:[/h] Of 14,500 Y1 participants, 7643 re-enrolled in Y2. Relative to participants who received IIV-SD both seasons, VE was higher for IIV-HD vaccinees in Y2 (28.3% overall; 25.1% for Y1 IIV-HD, Y2 IIV-HD; and 31.6% for Y1 IIV-SD, Y2 IIV-HD). In multivariate logistic regression models, Y1 vaccine was not a significant modifier of Y2 VE (p=0.43), while Y2 IIV-HD remained significantly associated with lower influenza risk (p=0.043). Compared to administration of IIV-SD in both years, post-vaccination HAI titers were significantly higher for patterns that included IIV-HD in Y2. No safety concerns were raised with IIV-HD revaccination.
[h=4]CONCLUSIONS:[/h] IIV-HD is likely to provide clinical benefit over IIV-SD irrespective of previous season vaccination with IIV-HD or IIV-SD. IIV-HD consistently improved immune responses, and no safety concerns emerged in the context of IIV-HD revaccination.
? The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America.
PMID: 26908801 [PubMed - as supplied by publisher]
[h=1]Effect of previous year vaccination on the efficacy, immunogenicity, and safety of high-dose inactivated influenza vaccine in older adults.[/h] DiazGranados CA[SUP]1[/SUP], Dunning AJ[SUP]1[/SUP], Robertson CA[SUP]1[/SUP], Talbot HK[SUP]2[/SUP], Landolfi V[SUP]1[/SUP], Greenberg DP[SUP]3[/SUP].
[h=3]Author information[/h]
[h=3]Abstract[/h] [h=4]BACKGROUND:[/h] high-dose inactivated influenza vaccine (IIV-HD) is an alternative to the standard-dose inactivated influenza vaccine (IIV-SD) in the US for influenza prevention in older adults. IIV-HD improved efficacy relative to IIV-SD in a randomized controlled trial. Recent observational studies suggest that previous influenza vaccination may influence the immunogenicity and effectiveness of current-season vaccination.
[h=4]METHODS:[/h] the original study was a double-blind, randomized trial comparing IIV-HD to IIV-SD in adults ≥65 years over two influenza seasons. A subset of year 1 (Y1) participants re-enrolled in year 2 (Y2), receiving vaccine by random assignment in both years. We evaluated the effect of Y1 vaccination on Y2 relative vaccine efficacy (VE), immunogenicity (hemagglutination inhibition [HAI] titers), and safety among re-enrolled participants.
[h=4]RESULTS:[/h] Of 14,500 Y1 participants, 7643 re-enrolled in Y2. Relative to participants who received IIV-SD both seasons, VE was higher for IIV-HD vaccinees in Y2 (28.3% overall; 25.1% for Y1 IIV-HD, Y2 IIV-HD; and 31.6% for Y1 IIV-SD, Y2 IIV-HD). In multivariate logistic regression models, Y1 vaccine was not a significant modifier of Y2 VE (p=0.43), while Y2 IIV-HD remained significantly associated with lower influenza risk (p=0.043). Compared to administration of IIV-SD in both years, post-vaccination HAI titers were significantly higher for patterns that included IIV-HD in Y2. No safety concerns were raised with IIV-HD revaccination.
[h=4]CONCLUSIONS:[/h] IIV-HD is likely to provide clinical benefit over IIV-SD irrespective of previous season vaccination with IIV-HD or IIV-SD. IIV-HD consistently improved immune responses, and no safety concerns emerged in the context of IIV-HD revaccination.
? The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America.
PMID: 26908801 [PubMed - as supplied by publisher]