title: Preexisting Immunity, More Than Aging, Influences Influenza Vaccine Responses.
abstract: Background.  Influenza disproportionately impacts older adults while current vaccines have reduced effectiveness in the older population. Methods.  We conducted a comprehensive evaluation of cellular and humoral immune responses of adults aged 50 years and older to the 2008-2009 seasonal trivalent inactivated influenza vaccine and assessed factors influencing vaccine response. Results.  Vaccination increased hemagglutination inhibition and neutralizing antibody; however, 66.3% of subjects did not reach hemagglutination inhibition titers ≥ 40 for H1N1, compared with 22.5% for H3N2. Increasing age had a minor negative impact on antibody responses, whereas prevaccination titers were the best predictors of postvaccination antibody levels. Preexisting memory B cells declined with age, especially for H3N2. However, older adults still demonstrated a significant increase in antigen-specific IgG(+) and IgA(+) memory B cells postvaccination. Despite reduced frequency of preexisting memory B cells associated with advanced age, fold-rise in memory B cell frequency in subjects 60+ was comparable to subjects age 50-59. Conclusions.  Older adults mounted statistically significant humoral and cell-mediated immune responses, but many failed to reach hemagglutination inhibition titers ≥40, especially for H1N1. Although age had a modest negative effect on vaccine responses, prevaccination titers were the best predictor of postvaccination antibody levels, irrespective of age.
authors.affiliation: Influenza Division, National Center for Immunization and Respiratory Diseases , Centers for Disease Control and Prevention , Atlanta, Georgia.
authors.forename: Adrian J
authors.initials: AJ
authors.lastname: Reber
authors.affiliation: Influenza Division, National Center for Immunization and Respiratory Diseases , Centers for Disease Control and Prevention , Atlanta, Georgia.
authors.forename: Jin Hyang
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Influenza Division, National Center for Immunization and Respiratory Diseases , Centers for Disease Control and Prevention , Atlanta, Georgia.
authors.forename: Renata
authors.initials: R
authors.lastname: Biber
authors.affiliation: Vanderbilt University Medical Center , Nashville, Tennessee.
authors.forename: H Keipp
authors.initials: HK
authors.lastname: Talbot
authors.affiliation: Marshfield Clinic Research Foundation , Wisconsin.
authors.forename: Laura A
authors.initials: LA
authors.lastname: Coleman
authors.affiliation: Influenza Division, National Center for Immunization and Respiratory Diseases , Centers for Disease Control and Prevention , Atlanta, Georgia.
authors.forename: Tatiana
authors.initials: T
authors.lastname: Chirkova
authors.affiliation: Influenza Division, National Center for Immunization and Respiratory Diseases , Centers for Disease Control and Prevention , Atlanta, Georgia.
authors.forename: F Liaini
authors.initials: FL
authors.lastname: Gross
authors.affiliation: Influenza Division, National Center for Immunization and Respiratory Diseases , Centers for Disease Control and Prevention , Atlanta, Georgia.
authors.forename: Evelene
authors.initials: E
authors.lastname: Steward-Clark
authors.affiliation: Influenza Division, National Center for Immunization and Respiratory Diseases , Centers for Disease Control and Prevention , Atlanta, Georgia.
authors.forename: Weiping
authors.initials: W
authors.lastname: Cao
authors.affiliation: Influenza Division, National Center for Immunization and Respiratory Diseases , Centers for Disease Control and Prevention , Atlanta, Georgia.
authors.forename: Stacie
authors.initials: S
authors.lastname: Jefferson
authors.affiliation: Influenza Division, National Center for Immunization and Respiratory Diseases , Centers for Disease Control and Prevention , Atlanta, Georgia.
authors.forename: Vic
authors.initials: V
authors.lastname: Veguilla
authors.affiliation: Influenza Division, National Center for Immunization and Respiratory Diseases , Centers for Disease Control and Prevention , Atlanta, Georgia.
authors.forename: Eric
authors.initials: E
authors.lastname: Gillis
authors.affiliation: Marshfield Clinic Research Foundation , Wisconsin.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Meece
authors.affiliation: Influenza Division, National Center for Immunization and Respiratory Diseases , Centers for Disease Control and Prevention , Atlanta, Georgia.
authors.forename: Yaohui
authors.initials: Y
authors.lastname: Bai
authors.affiliation: Influenza Division, National Center for Immunization and Respiratory Diseases , Centers for Disease Control and Prevention , Atlanta, Georgia.
authors.forename: Heather
authors.initials: H
authors.lastname: Tatum
authors.affiliation: Influenza Division, National Center for Immunization and Respiratory Diseases , Centers for Disease Control and Prevention , Atlanta, Georgia.
authors.forename: Kathy
authors.initials: K
authors.lastname: Hancock
authors.affiliation: Influenza Division, National Center for Immunization and Respiratory Diseases , Centers for Disease Control and Prevention , Atlanta, Georgia.
authors.forename: James
authors.initials: J
authors.lastname: Stevens
authors.affiliation: Influenza Division, National Center for Immunization and Respiratory Diseases , Centers for Disease Control and Prevention , Atlanta, Georgia.
authors.forename: Sarah
authors.initials: S
authors.lastname: Spencer
authors.affiliation: Influenza Division, National Center for Immunization and Respiratory Diseases , Centers for Disease Control and Prevention , Atlanta, Georgia.
authors.forename: Jufu
authors.initials: J
authors.lastname: Chen
authors.affiliation: Influenza Division, National Center for Immunization and Respiratory Diseases , Centers for Disease Control and Prevention , Atlanta, Georgia.
authors.forename: Paul
authors.initials: P
authors.lastname: Gargiullo
authors.affiliation: Influenza Division, National Center for Immunization and Respiratory Diseases , Centers for Disease Control and Prevention , Atlanta, Georgia.
authors.forename: Elise
authors.initials: E
authors.lastname: Braun
authors.affiliation: Vanderbilt University Medical Center , Nashville, Tennessee ; Mid-South Geriatric Research Education and Clinical Center , VA TN Valley Healthcare System , Nashville, Tennessee.
authors.forename: Marie R
authors.initials: MR
authors.lastname: Griffin
authors.affiliation: Marshfield Clinic Research Foundation , Wisconsin.
authors.forename: Maria
authors.initials: M
authors.lastname: Sundaram
authors.affiliation: Marshfield Clinic Research Foundation , Wisconsin.
authors.forename: Edward A
authors.initials: EA
authors.lastname: Belongia
authors.affiliation: Influenza Division, National Center for Immunization and Respiratory Diseases , Centers for Disease Control and Prevention , Atlanta, Georgia.
authors.forename: David K
authors.initials: DK
authors.lastname: Shay
authors.affiliation: Influenza Division, National Center for Immunization and Respiratory Diseases , Centers for Disease Control and Prevention , Atlanta, Georgia.
authors.forename: Jacqueline M
authors.initials: JM
authors.lastname: Katz
authors.affiliation: Influenza Division, National Center for Immunization and Respiratory Diseases , Centers for Disease Control and Prevention , Atlanta, Georgia.
authors.forename: Suryaprakash
authors.initials: S
authors.lastname: Sambhara
keywords: aging; immune response; influenza; older adults; vaccine