Abstract
BackgroundThe influence of prior seasonal influenza vaccination on the antibody response produced by natural infection or vaccination is not well understood.MethodsWe compared the profiles of antibody responses of 32 naturally infected subjects and 98 subjects vaccinated with a 2009 influenza A(H1N1) monovalent MF59-adjuvanted vaccine (Focetria®, Novartis), with and without a history of seasonal influenza vaccination. Antibodies were measured by hemagglutination inhibition (HI) assay for influenza A(H1N1)pdm09 and by protein microarray (PA) using the HA1 subunit for seven recent and historic H1, H2 and H3 influenza viruses, and three avian influenza viruses. Serum samples for the infection group were taken at the moment of collection of the diagnostic sample, 10 days and 30 days after onset of influenza symptoms. For the vaccination group, samples were drawn at baseline, 3 weeks after the first vaccination and 5 weeks after the second vaccination.ResultsWe showed that subjects with a history of seasonal vaccination generally exhibited higher baseline titers for the various HA1 antigens than subjects without a seasonal vaccination history. Infection and pandemic influenza vaccination responses in persons with a history of seasonal vaccination were skewed towards historic antigens.ConclusionsSeasonal vaccination is of significant influence on the antibody response to subsequent infection and vaccination, and further research is needed to understand the effect of annual vaccination on protective immunity.
Highlights
The first influenza pandemic of the 21st century was caused by a novel influenza A(H1N1) virus, which was a complex reassortant virus containing genes from avian, human, and swine influenza viruses. [1] Hemagglutinin (HA) rapidly and continuously accumulates mutations to escape recognition by virus-specific antibodies
An important question is whether the presence of such broad non-neutralising antibodies may somehow influence infection. This discussion was further triggered because of the observed discrepancy between the population immunity estimates based on serology and the observed impact: cross-neutralizing antibodies were found in persons exposed to historic influenza A(H1N1) strains that were circulating prior to the emergence of the pandemic influenza H2N2 strain in 1956/57
[7] Wrammert et al [8] identified broadly cross-reactive neutralizing antibodies induced by infection between the influenza A(H1N1)pdm09, recent seasonal influenza A(H1N1) strains, as well as influenza A(H1N1)1918, and avian influenza viruses of subtypes H5N1
Summary
The first influenza pandemic of the 21st century was caused by a novel influenza A(H1N1) virus, which was a complex reassortant virus containing genes from avian, human, and swine influenza viruses. [1] Hemagglutinin (HA) rapidly and continuously accumulates mutations to escape recognition by virus-specific antibodies. [3] The occasional zoonotic transmissions, and the opportunity for human adaptation of animal influenza viruses through reassortment or adaptation, constitute a continuous pandemic threat, as illustrated by the recent pandemic in 2009. Impact of such a new introduction is determined in part by the level of pre-existing immunity in the population. [7] Wrammert et al [8] identified broadly cross-reactive neutralizing antibodies induced by infection between the influenza A(H1N1)pdm, recent seasonal influenza A(H1N1) strains, as well as influenza A(H1N1)1918, and avian influenza viruses of subtypes H5N1. The influence of prior seasonal influenza vaccination on the antibody response produced by natural infection or vaccination is not well understood
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