title: Long-term and cross-reactive immunogenicity of inactivated trivalent influenza vaccine in the elderly: MF59-adjuvanted vaccine versus unadjuvanted vaccine.
abstract: Elderly people are at great risk for influenza-related serious complications. However, influenza vaccine-induced antibodies are believed to decline more rapidly in the elderly. This study was designed to evaluate the long-term and cross-reactive immunogenicity among those aged ≥65 years for two seasonal trivalent influenza vaccines during the 2009-2010 influenza season. One vaccine had the MF59 adjuvant, while the other did not contain an adjuvant. Serum hemagglutinin inhibition (HI) titers were determined pre-vaccination and at 1 and 6 months post-vaccination. Of the 100 subjects, 95 (95%) were followed-up for 1 month after vaccination, and 76 (76%) were followed-up for 6 months after vaccination. Both vaccines met the European Medicines Agency (EMA) criteria 1 month after vaccination. However, seroprotection for influenza B was not satisfactory, with a rate of 55.3% for the MF59 adjuvant vaccine and 47.9% for the vaccine without adjuvant. At 6 months post-vaccination, the MF59-adjuvanted vaccine showed a higher seroprotection rate than the unadjuvanted vaccine. At this point, the MF59-adjuvanated vaccine still met the criteria of EMA for A/H1N1 (62.5% vs. 55.5%, P = 0.64) and A/H3N2 (72.5% vs. 47.2%, P = 0.04). Both vaccines showed excellent cross-reactive immunogenicity for influenza A/Solomon Island/3/2006 (H1N1) and A/Wisconsin/67/2005 (H3N2), without significant differences. In comparison, cross-reactive immunogenicity was not remarkable for the A/California/7/2009 (H1N1) and A/New Caledonia/20/1999 (H1N1) strains, which have a greater antigenic distance. In conclusion, the MF59-adjuvanted influenza vaccine showed superior long-term immunogenicity in the elderly compared to the unadjuvanted vaccine. However, cross-reactive immunogenicity was not remarkably enhanced with the MF59 adjuvant.
authors.affiliation: Division of Infectious Diseases, Department of Internal Medicine, Korea University College of Medicine, Seoul, Republic of Korea.
authors.forename: Joon Young
authors.initials: JY
authors.lastname: Song
authors.forename: Hee Jin
authors.initials: HJ
authors.lastname: Cheong
authors.forename: Ji Yun
authors.initials: JY
authors.lastname: Noh
authors.forename: Yu Bin
authors.initials: YB
authors.lastname: Seo
authors.forename: Won Suk
authors.initials: WS
authors.lastname: Choi
authors.forename: Geum Joo
authors.initials: GJ
authors.lastname: Cho
authors.forename: Taik Gun
authors.initials: TG
authors.lastname: Hwang
authors.forename: Woo Joo
authors.initials: WJ
authors.lastname: Kim
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage*; D000368:Aged; D000369:Aged, 80 and over; D000914:Antibodies, Viral / Q000097:blood; D003429:Cross Reactions; D005260:Female; D006385:Hemagglutination Inhibition Tests; D006801:Humans; D007252:Influenza Vaccines / Q000008:administration & dosage* / Q000276:immunology*; D007251:Influenza, Human / Q000517:prevention & control*; D008297:Male; D011136:Polysorbates / Q000008:administration & dosage*; D013185:Squalene / Q000008:administration & dosage*; D014611:Vaccination / Q000379:methods*; D015164:Vaccines, Inactivated / Q000008:administration & dosage / Q000009:adverse effects
chemical_list: D000276:Adjuvants, Immunologic; D000914:Antibodies, Viral; D007252:Influenza Vaccines; C089950:MF59 oil emulsion; D011136:Polysorbates; D015164:Vaccines, Inactivated; D013185:Squalene
keywords: MF59 adjuvant; elderly; immunogenicity; influenza vaccine