An Inactivated,Adjuvanted Whole Virion Clade 2.2 H5N1 (A/Chicken/Astana/6/05) Influenza Vaccine Is Safe and Immunogenic in a Single Dose in Humans |
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Authors: | Abylay R. Sansyzbay Marianna K. Erofeeva Berik M. Khairullin Nurlan T. Sandybayev Zhailaubay K. Kydyrbayev Seidigapbar M. Mamadaliyev Markhabat M. Kassenov Maria V. Sergeeva Julia R. Romanova Vera Z. Krivitskaya Oleg I. Kiselev Marina A. Stukova |
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Affiliation: | Research Institute for Biological Safety Problems, Gvardeiskiy, Kazakhstana;Research Institute of Influenza, Saint Petersburg, Russiab |
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Abstract: | In this study, we assessed in humans the immunogenicity and safety of one dose (7.5 or 15 μg of hemagglutinin [HA]) of a whole-virion inactivated prepandemic influenza vaccine adjuvanted with aluminum hydroxide. The vaccine strain was made by reverse genetics from the highly pathogenic avian A/Chicken/Astana/6/05 (H5N1) clade 2.2 strain isolated from a dead bird in Kazakhstan. The humoral immune response was evaluated after a single vaccination by hemagglutination inhibition (HI) and microneutralization (MN) assays. The vaccine was safe and immunogenic, inducing seroconversion in 55% of the evaluated patients, with a geometric mean titer (GMT) of 17.1 and a geometric mean increase (GMI) of 3.42 after a dose of 7.5 μg in the HI test against the vaccine strain. The rate of seroconversion increased up to 70% when the dose of 15 μg was used. The percentages of individuals achieving anti-HA titers of ≥1:40 were 52.5% and 57.5% for the 7.5- and 15-μg dose groups, respectively. Similar results were obtained when antibodies were analyzed in an MN test. Substantial cross-neutralization titers (seroconversion in 35% and 52.5% of subjects in the two dose groups, respectively) were detected against heterologous clade 1 strain NIBRG14 (H5N1). Thus, one dose of this whole-virion prepandemic vaccine adjuvanted with aluminum has the potential to be effective against H5N1 viruses of different clades. |
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