title: Comparison of the long-term immunogenicity of two pandemic influenza A/H1N1 2009 vaccines, the MF59-adjuvanted and unadjuvanted vaccines, in adults.
abstract: Since the first reports of the A/H1N1 virus in April 2009, the pandemic influenza virus spread globally and circulated for a long time. The primary method for the control of influenza is vaccination, but levels of influenza vaccine-induced antibody are known to decline rapidly during a 6-month period. In adults aged 18 to 64 years, we compared the long-term immunogenicity of two of the influenza A/H1N1 2009 monovalent vaccines, 3.75-μg MF59-adjuvanted vaccine and 15-μg unadjuvanted vaccine. The serum hemagglutinin inhibition (HI) titers were determined prevaccination and at 1, 6, and 10 months after vaccination. One hundred six (88.3%) of the 120 subjects were monitored for the entire 10-month period after receiving the influenza A/H1N1 2009 monovalent vaccine. There were 60 patients who received the unadjuvanted vaccine and 46 patients who received the MF59-adjuvanted vaccine. The seroprotection rates, seroconversion rates, and the geometric mean titer (GMT) folds fulfilled the criteria of the European Medicines Agency (EMA) for influenza A/California/7/2009 (H1N1) at 1 month after vaccination irrespective of the vaccine composition. Although the GMTs at 1 month postvaccination were somewhat higher in the unadjuvanted vaccine recipients than in the MF59-adjuvanted vaccine recipients, the difference was not significant (P = 0.29). The seroprotection rates at 6 and 10 months postvaccination were preserved above 70% but only in the MF59-adjuvanted vaccine recipients. In conclusion, low-dose MF59-adjuvanted influenza vaccine, even with 3.75 μg hemagglutinin antigen, might induce excellent long-term immunity that is comparable to the conventional dose of unadjuvanted vaccine among healthy adults aged 18 to 64 years.
authors.affiliation: Division of Infectious Diseases, Department of Internal Medicine, Korea University College of Medicine, Seoul, South Korea.
authors.forename: Joon Young
authors.initials: JY
authors.lastname: Song
authors.forename: Hee Jin
authors.initials: HJ
authors.lastname: Cheong
authors.forename: Yu Bin
authors.initials: YB
authors.lastname: Seo
authors.forename: In Seon
authors.initials: IS
authors.lastname: Kim
authors.forename: Ji Yun
authors.initials: JY
authors.lastname: Noh
authors.forename: Jung Yeon
authors.initials: JY
authors.lastname: Heo
authors.forename: Won Suk
authors.initials: WS
authors.lastname: Choi
authors.forename: Jacob
authors.initials: J
authors.lastname: Lee
authors.forename: Woo Joo
authors.initials: WJ
authors.lastname: Kim
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage; D000293:Adolescent; D000328:Adult; D000914:Antibodies, Viral / Q000097:blood; D005260:Female; D006385:Hemagglutination Inhibition Tests; D006801:Humans; D007156:Immunologic Memory; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology*; D007252:Influenza Vaccines / Q000008:administration & dosage / Q000276:immunology*; D007251:Influenza, Human / Q000276:immunology / Q000517:prevention & control* / Q000821:virology*; D008297:Male; D008875:Middle Aged; D011136:Polysorbates / Q000008:administration & dosage; D013185:Squalene / Q000008:administration & dosage; D013997:Time Factors; D055815:Young Adult
chemical_list: D000276:Adjuvants, Immunologic; D000914:Antibodies, Viral; D007252:Influenza Vaccines; C089950:MF59 oil emulsion; D011136:Polysorbates; D013185:Squalene