title: The long-term immunogenicity of an inactivated split-virion 2009 pandemic influenza A H1N1 vaccine: Randomized, observer-masked, single-center clinical study.
abstract: The aim of this study is to investigate the long-term immunogenicity of inactivated split-virion 2009 pandemic influenza A H1N1 vaccine after a single immunization. We recruited 480 adults, aged 18-60 years, for a placebo-controlled, observer-masked, single-center clinical study. We randomly assigned subjects into four groups: 15 μg, 30 μg and 45 μg of hemagglutinin (HA) dosage groups, and a placebo control group. Finally, 259 subjects completed the entire study. The rates of seroconversion and seroprotection and the geometric mean increase (GMI) fulfilled the criteria of the European Medicines Agency (EMEA) for influenza vaccine for 180 days after vaccination in all three dosage groups. However, the seroprotection rates of all dosage groups were below 70% at day 360 post vaccination, while the seroconversion rates and the GMI continued to meet the licensure criteria at this time point. In conclusion, a single dose of 15 μg HA vaccine could induce a protective immune response persisting for at least six months in adults. This study could be beneficial for the future development of influenza vaccines conferring long-term immunity.
authors.affiliation: Shanghai Institute of Biological Products, Shanghai 200052, China.
authors.forename: Zhongdong
authors.initials: Z
authors.lastname: Yang
authors.affiliation: Shanghai Institute of Biological Products, Shanghai 200052, China.
authors.forename: Shilei
authors.initials: S
authors.lastname: Wang
authors.affiliation: National Institute for the Control of Pharmaceuticals and Biological Products, Beijing, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.affiliation: National Institute for the Control of Pharmaceuticals and Biological Products, Beijing, China.
authors.forename: Changgui
authors.initials: C
authors.lastname: Li
authors.affiliation: Shanghai Institute of Biological Products, Shanghai 200052, China.
authors.forename: Jinrong
authors.initials: J
authors.lastname: Dong
authors.affiliation: Hunan Provincial Center of Disease Prevention and Control, Changsha, Hunan, China.
authors.forename: Fangjun
authors.initials: F
authors.lastname: Li
authors.affiliation: Shanghai Institute of Biological Products, Shanghai 200052, China.
authors.forename: Shuqiao
authors.initials: S
authors.lastname: Wang
authors.affiliation: Shanghai Institute of Biological Products, Shanghai 200052, China.
authors.forename: Wenqing
authors.initials: W
authors.lastname: Chai
authors.affiliation: Institute Pasteur of Shanghai, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China.
authors.forename: Bing
authors.initials: B
authors.lastname: Sun
authors.affiliation: Shanghai Institute of Biological Products, Shanghai 200052, China.
authors.forename: Ze
authors.initials: Z
authors.lastname: Chen
keywords: H1N1; Hemagglutinin (HA); Immunogenicity; Influenza; Long-term