Immunogenicity of Three Different Influenza Vaccines against Homologous and Heterologous Strains in Nursing Home Elderly Residents

Abstract

We studied whether MF59-adjuvanted influenza vaccine improves immunity against drifted influenza strains in institutionalised elderly with underling chronic health conditions. Sera from a randomized study, comparing MF59-adjuvanted (Sub/MF59, n = 72), virosomal (SVV, n = 39), and split (n = 88) vaccines, were retested using a hemagglutination inhibition (HI) assay against homologous (Northern Hemisphere [NH] 1998/99) and drifted (NH 2006/07) strains. Corrected postvaccination HI antibody titres were significantly higher with Sub/MF59 than SVV for all strains; GMTs against homologous A/H3N2 and B and both drifted A strains were significantly higher for Sub/MF59 than split. Seroprotection rates and mean-fold titer increases were generally higher with Sub/MF59 for all A influenza strains. MF59-adjuvanted influenza vaccine induced greater and broader immune responses in elderly people with chronic conditions, than conventional virosomal and split vaccines, particularly for A/H1 and A/H3 strains, potentially giving clinical benefit in seasons where antigenic mismatch occurs.

Immunogenicity of intramuscular MF59-adjuvanted and intradermal administered influenza enhanced vaccines in subjects aged over 60: A literature review

“…Previous published studies have established that the immune response induced by IM-MF59 and ID potentiated vaccines, specially licensed for elderly people and marketed in Italy in 1997 and 2010 respectively, can be considered higher in elderly people as compared to conventional vaccines 4,28,29,35,[37][38][39][40]45,46,50,51,54,56,58,59 ; however, it is unclear if one of the 2 potentiated vaccines offers any advantages.…”

“…Finally, some of the trials examined 35,37,40,42,43,46,49,55,[57][58][59] studied the induction of heterologous HI antibody responses, i.e., responses against influenza strains not included in the vaccine used for immunization, following immunization with IM-MF59 and ID vaccines and found results generally satisfying all or at least some of the EMA requirements ( Table 3). …”

“…Table 3 reports data demonstrating that IM-MF59-adjuvanted and ID vaccines have been found reproducibly to confer cross-reactivity against drifted virus strains in the elderly patients aged 60. 35,37,40,42,43,46,49,55,[57][58][59] HI antibody responses against A/H3N2 co-circulating during the winter period studied 37,57,58 and A/H3N2 strains recommended as vaccine component for previous or forthcoming winter seasons 35,40,43,46,49,55 were found to fulfill in most instances all the 3 or at least 2 EMA immunogenicity criteria both after IM-MF59 35,37,40,43,46,49,55 or ID 57,58 vaccine administration. Similar results were obtained studying antibody responses induced by IM-MF59 40,43,55 or ID 59 vaccines against A/H1N1 chosen as vaccine strain for forthcoming winter season 40,43,55 or A/H1N1 circulating among the population.…”

“…4,30,31,35, These studies recruited subjects who would normally be candidates for routine seasonal influenza vaccination and the strain composition of the influenza vaccines used conformed to the yearly requirements of the World Health Organization. The population consisted of elderly subjects with and without underlying diseases, 30,35,[37][38][39][40][41][42]56,57 with unknown health status [43][44][45][46][47][48] or healthy. 4,31,[49][50][51][52][53][54][55] No sub-analyses were conducted to evaluate potential differences in the outcome between these groups.…”

“…59 Induction of cross-reactive HI antibodies against influenza B virus strain was examined only after IM-MF59 vaccination in 3 different studies. 40,42,43 Influenza B viruses fall in 2 major antigenically and genetically distinct lineages, B/Victoria and B/ Yamagata, co-circulating in some years among the population and currently in many countries only one type B strain, representing one of the 2 lineages, can be incorporated into the vaccine. 62,63 Increases in HI antibody titers were found against drifted B strains, both belonging to the same or different lineage as compared to vaccine strain.…”