Seroepidemiological study of influenza A (H1N1) pdm09 virus following the 2009-2010 wave in Shandong Province, China

• Published in: Scandinavian journal of infectious diseases Vol. 45; no. 7; pp. 552 - 556
• Main Authors: Liu, Ti, Li, Zhong, Song, Shaoxia, Zhang, Shengyang, Wang, Yulu, Wang, Lanying, Xu, Aiqiang, Wang, Xianjun, Bi, Zhenqiang
• Format: Journal Article
• Language: English
• Published: England Informa Healthcare 01.07.2013; Taylor & Francis
• Subjects: Adolescent; Adult; Aged; Aged, 80 and over; Antibodies, Viral - blood; Child; Child, Preschool; China; China - epidemiology; Cross-Sectional Studies; Female; Hemagglutination Inhibition Tests; Humans; Infant; Infant, Newborn; Influenza A (H1N1) pdm09; Influenza A Virus, H1N1 Subtype - immunology; Influenza, Human - epidemiology; Influenza, Human - virology; Male; Middle Aged; Seroepidemiologic Studies; seropositive rate; Young Adult; China
• ISSN: 0036-5548; 1651-1980; 1651-1980
• DOI: 10.3109/00365548.2013.793818

Abstract Introduction: The aims of this study were to understand the geographic extent, risk factors, and attack rate of influenza A (H1N1) pdm09 virus (pH1N1) infection in Shandong Province China and to elucidate influencing factors. Methods: In January and March 2010, a cross-sectional seroprevalence survey of pH1N1 was carried out. Serum samples from 9022 participants in the survey were subjected to the hemagglutination inhibition assay. Results: Among the 9022 participants, the overall rate of seropositivity against pH1N1 was 22.6%. The weighted rate, adjusted for gender, age, and region, was estimated to be 18.7%. Among 8340 subjects who did not report previous vaccination, the rate was 16.7%, as compared to 50.9% among 682 subjects reporting previous vaccination (p < 0.001). Within the unvaccinated population, the rate of seropositivity among 16-24 and 6-15 y-old subjects was 31.8% and 29.9%, respectively, as compared to 9.6% among subjects aged ≥ 60 y (p < 0.001) and 23% in the 0-5 y age group (p < 0.001). Those aged 6-15 y and aged 16-24 y had higher odds of seropositivity than those aged 0-5 y (odds ratio 1.53 and 1.48, respectively). Conclusions: These study findings help enhance our understanding of pH1N1 epidemiology and provide valuable information for the vaccination strategy for the influenza season.