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.

Preexisting Immunity, Not Frailty Phenotype, Predicts Influenza Postvaccination Titers among Older Veterans

“…This is consistent with a previously published report by Reber and colleagues, in which prevaccination titers were the best predictor of postvaccination immunity to influenza among adults older than 50 years of age (13). In fact, those authors found age to be only modestly associated with lower vaccine responses.…”

“…These rates did not differ by frailty status. Our observed rates of seroprotection were similar to findings reported for older adults, including greater immune protection against A(H3N2) (13). Incidentally, among older adults, A(H3N2) virus has been found to be associated with more severe morbidity and increased mortality rates, compared with A (H1N1)pdm09 (2, 3).…”

“…One source of variability is preexisting immunity to influenza. In fact, preexisting immunity to influenza has been proposed as a greater correlate of immunity to influenza than age among elderly persons (13). Another potential source of variable responses to influenza vaccines is functional decline or frailty.…”

Cell-Mediated Immunity Against Antigenically Drifted Influenza A(H3N2) Viruses in Children During a Vaccine Mismatch Season

“…Virus-specific PBs, also known as Ab-secreting cells (ASCs), were evaluated by an ex vivo enzyme-linked immunospot (ELISPOT) assay as previously described [15]. Briefly, day 0 and day 7 paired sets of PBMCs were directly placed onto A (H3N2) virus-coated ELISPOT plates (100 hemagglutinin units/well) overnight, and ASCs were detected through enzymatic reaction.…”

Hubungan Status Frailty dengan Serokonversi dan Seroproteksi Vaksin Influenza pada Populasi Usia Lanjut

“…Semakin tua usia seseorang, respon imunnya akan semakin buruk. 8 Respon yang berbeda pada usia lanjut ini diperkirakan karena frailty dan kejadian immunosenescense yang mendasarinya. Kejadian frailty ini ternyata cukup sering, Collerton, dkk.…”