TITLE:
Prevaccination Antibody Confers Additional Immune Responses to Repeated Yearly Influenza Vaccination in an Elderly Population
AUTHORS:
Satoko Kitamura, Naoki Komatsu, Masahide Matsushita, Hiromi Seo, Seisho Takeuchi
KEYWORDS:
Influenza Vaccine, Elderly Persons, Repeated Vaccination, Seroprotection Rate
JOURNAL NAME:
World Journal of Vaccines,
Vol.12 No.2,
November
7,
2022
ABSTRACT: Annual vaccination is necessary to maintain humoral immunity in the
elderly population. However, the factors influencing the response to influenza
vaccination have not been completely identified. The aim of this study was to
explore the factors that influenced antibody responses to repeated vaccination
using measures that were both objective and quantitative. A total of 111
volunteers aged > 61 years were vaccinated subcutaneously with one dose of
influenza vaccine from the 2005-2006 season through the 2009-2010 season. The
factors that influenced antibody responses after vaccination were evaluated.
The seroprotection rates (PRs) were significantly higher in responders
(subjects with a higher antibody titer in the 2005-2006 season) than in
nonresponders only in the 2006-2007 and 2007-2008 seasons. PRs after
vaccination were significantly higher in seropositive individuals (subjects
with a higher prevaccination antibody titer in the 2006-2007 season) than in
seronegative individuals for all three virus strains in almost all of the 5
years. Age, gender, and vaccination in the 2004-2005 season did not influence
the response. These results suggest that an immune response at a certain time
point would predict immune responses only in the near future. However,
prevaccination antibody titer in the following season is the ideal predictor
for future responses that last over several influenza seasons.