tetano
Editor, Senior Moderator
J Infect Dis. 2017 Mar 15;215(6):847-855. doi: 10.1093/infdis/jix055.
[h=1]Effect of Repeated Vaccination With the Same Vaccine Component Against 2009 Pandemic Influenza A(H1N1) Virus.[/h] Mart?nez-Baz I[SUP]1,[/SUP][SUP]2[/SUP], Casado I[SUP]1,[/SUP][SUP]2[/SUP], Navascu?s A[SUP]3[/SUP], D?az-Gonz?lez J[SUP]1[/SUP], Aguinaga A[SUP]3[/SUP], Barrado L[SUP]4[/SUP], Delfrade J[SUP]1,[/SUP][SUP]2[/SUP], Ezpeleta C[SUP]3[/SUP], Castilla J[SUP]1,[/SUP][SUP]2[/SUP].
[h=3]Author information[/h]
[h=3]Abstract[/h] [h=4]Background.:[/h] The 2009 pandemic influenza A(H1N1) (A[H1N1]pdm09) vaccine component has remained unchanged from 2009. We estimate the effectiveness of current and prior inactivated influenza A(H1N1)pdm09 vaccination from influenza seasons 2010-2011 to 2015-2016.
[h=4]Methods.:[/h] Patients attended with influenza-like illness were tested for influenza. Four periods with continued A(H1N1)pdm09 circulation were included in a test-negative design.
[h=4]Results.:[/h] We enrolled 1278 cases and 2343 controls. As compared to individuals never vaccinated against influenza A(H1N1)pdm09, the highest effectiveness (66%; 95% confidence interval, 49%-78%) was observed in those vaccinated in the current season who had received 1-2 prior doses. The effectiveness was not statistically lower in individuals vaccinated in the current season only (52%) or in those without current vaccination and >2 prior doses (47%). However, the protection was lower in individuals vaccinated in the current season after >2 prior doses (38%; P = .009) or those currently unvaccinated with 1-2 prior doses (10%; P < .001). Current-season vaccination improved the effect in individuals with 1-2 prior doses and did not modify significantly the risk of influenza in individuals with >2 prior doses.
[h=4]Conclusion.:[/h] Current vaccination or several prior doses were needed for high protection. Despite the decreasing effect of repeated vaccination, current-season vaccination was not inferior to no current-season vaccination.
[h=4]KEYWORDS:[/h] A(H1N1)pdm09 virus.; Influenza; case control study; influenza vaccine; vaccine effectiveness
PMID: 28453845 DOI: 10.1093/infdis/jix055
[h=1]Effect of Repeated Vaccination With the Same Vaccine Component Against 2009 Pandemic Influenza A(H1N1) Virus.[/h] Mart?nez-Baz I[SUP]1,[/SUP][SUP]2[/SUP], Casado I[SUP]1,[/SUP][SUP]2[/SUP], Navascu?s A[SUP]3[/SUP], D?az-Gonz?lez J[SUP]1[/SUP], Aguinaga A[SUP]3[/SUP], Barrado L[SUP]4[/SUP], Delfrade J[SUP]1,[/SUP][SUP]2[/SUP], Ezpeleta C[SUP]3[/SUP], Castilla J[SUP]1,[/SUP][SUP]2[/SUP].
[h=3]Author information[/h]
[h=3]Abstract[/h] [h=4]Background.:[/h] The 2009 pandemic influenza A(H1N1) (A[H1N1]pdm09) vaccine component has remained unchanged from 2009. We estimate the effectiveness of current and prior inactivated influenza A(H1N1)pdm09 vaccination from influenza seasons 2010-2011 to 2015-2016.
[h=4]Methods.:[/h] Patients attended with influenza-like illness were tested for influenza. Four periods with continued A(H1N1)pdm09 circulation were included in a test-negative design.
[h=4]Results.:[/h] We enrolled 1278 cases and 2343 controls. As compared to individuals never vaccinated against influenza A(H1N1)pdm09, the highest effectiveness (66%; 95% confidence interval, 49%-78%) was observed in those vaccinated in the current season who had received 1-2 prior doses. The effectiveness was not statistically lower in individuals vaccinated in the current season only (52%) or in those without current vaccination and >2 prior doses (47%). However, the protection was lower in individuals vaccinated in the current season after >2 prior doses (38%; P = .009) or those currently unvaccinated with 1-2 prior doses (10%; P < .001). Current-season vaccination improved the effect in individuals with 1-2 prior doses and did not modify significantly the risk of influenza in individuals with >2 prior doses.
[h=4]Conclusion.:[/h] Current vaccination or several prior doses were needed for high protection. Despite the decreasing effect of repeated vaccination, current-season vaccination was not inferior to no current-season vaccination.
[h=4]KEYWORDS:[/h] A(H1N1)pdm09 virus.; Influenza; case control study; influenza vaccine; vaccine effectiveness
PMID: 28453845 DOI: 10.1093/infdis/jix055