Giuseppe
Emeritus
[Source: PLoS ONE, full page: (LINK). Abstract, edited.]
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Epidemiological and Virological Characteristics of Pandemic Influenza A (H1N1) School Outbreaks in China in 2009
Lei Yan<SUP>1</SUP><SUP>#</SUP>, Yan Gao<SUP>1</SUP><SUP>#</SUP>, Yong Zhang<SUP>2</SUP><SUP>#</SUP>, Michael Tildesley<SUP>3</SUP><SUP>,</SUP><SUP>4</SUP>, Liqi Liu<SUP>1</SUP>, Ye Zhang<SUP>1</SUP>, Leying Wen<SUP>1</SUP>, Wei Wang<SUP>1</SUP>, Xiaodan Li<SUP>1</SUP>, Ying Hu<SUP>1</SUP>, Tian Bai<SUP>1</SUP>, Min Wang<SUP>1</SUP>, Yuhong Zeng<SUP>1</SUP>, Dingming Wang<SUP>5</SUP>, Xianjun Wang<SUP>6</SUP>, Yu Lan<SUP>1</SUP>, Shiwen Wang<SUP>1</SUP><SUP>*</SUP>, Yuelong Shu<SUP>1</SUP><SUP>*</SUP>
<SUP></SUP>
1 State Key Laboratory for Molecular Virology and Genetic Engineering, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China, 2 School of Mathematical Sciences, Beijing Normal University, Beijing, China, 3 Centre for Complexity Science, Zeeman Building, University of Warwick, Coventry, United Kingdom, 4 US National Institutes of Health, Fogarty International Center, Bethesda, Maryland, United States of America, 5 Center for Disease Control and Prevention of Guizhou Province, GuiYang, China, 6 Center for Disease Control and Prevention of Shandong Province, Jinan, China
Abstract
Background
During the 2009 pandemic influenza H1N1 (2009) virus (pH1N1) outbreak, school students were at an increased risk of infection by the pH1N1 virus. However, the estimation of the attack rate showed significant variability.
Methods
Two school outbreaks were investigated in this study. A questionnaire was designed to collect information by interview. Throat samples were collected from all the subjects in this study 6 times and sero samples 3 times to confirm the infection and to determine viral shedding. Data analysis was performed using the software STATA 9.0.
Findings
The attack rate of the pH1N1 outbreak was 58.3% for the primary school, and 52.9% for the middle school. The asymptomatic infection rates of the two schools were 35.8% and 37.6% respectively. Peak virus shedding occurred on the day of ARI symptoms onset, followed by a steady decrease over subsequent days (p = 0.026). No difference was found either in viral shedding or HI titer between the symptomatic and the asymptomatic infectious groups.
Conclusions
School children were found to be at a high risk of infection by the novel virus. This may be because of a heightened risk of transmission owing to increased mixing at boarding school, or a lack of immunity owing to socio-economic status. We conclude that asymptomatically infectious cases may play an important role in transmission of the pH1N1 virus.
Citation: Yan L, Gao Y, Zhang Y, Tildesley M, Liu L, et al. (2012) Epidemiological and Virological Characteristics of Pandemic Influenza A (H1N1) School Outbreaks in China in 2009. PLoS ONE 7(9): e45898. doi:10.1371/journal.pone.0045898
Editor: Chiyu Zhang, Institut Pasteur of Shanghai, Chinese Academy of Sciences, China
Received: July 11, 2011; Accepted: August 23, 2012; Published: September 27, 2012
Copyright: ? 2012 Yan et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Funding: This study was supported by National Institutes of Health (NIH) Fund for the Special Program for Prevention and Control of Infectious Diseases (Grant No. 2008ZX10004-012), and NIH/NIAID Grant 5-U54-AI-057157-08 (Epidemiology and Molecular Mechanism of Highly Pathogenic Avian Influenza H5N1 and Pandemic Influenza H1N1). MT is supported by the Wellcome Trust, the RAPIDD program of the Science and Technology Directorate, Department of Homeland Security, and the Fogarty International Center, National Institutes of Health. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing interests: The authors have declared that no competing interests exist.
* E-mail: yshu@cnic.org.cn (YS); wangshiwencdc@163.com (SW)
# These authors contributed equally to this work.
-Lei Yan<SUP>1</SUP><SUP>#</SUP>, Yan Gao<SUP>1</SUP><SUP>#</SUP>, Yong Zhang<SUP>2</SUP><SUP>#</SUP>, Michael Tildesley<SUP>3</SUP><SUP>,</SUP><SUP>4</SUP>, Liqi Liu<SUP>1</SUP>, Ye Zhang<SUP>1</SUP>, Leying Wen<SUP>1</SUP>, Wei Wang<SUP>1</SUP>, Xiaodan Li<SUP>1</SUP>, Ying Hu<SUP>1</SUP>, Tian Bai<SUP>1</SUP>, Min Wang<SUP>1</SUP>, Yuhong Zeng<SUP>1</SUP>, Dingming Wang<SUP>5</SUP>, Xianjun Wang<SUP>6</SUP>, Yu Lan<SUP>1</SUP>, Shiwen Wang<SUP>1</SUP><SUP>*</SUP>, Yuelong Shu<SUP>1</SUP><SUP>*</SUP>
<SUP></SUP>
1 State Key Laboratory for Molecular Virology and Genetic Engineering, National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China, 2 School of Mathematical Sciences, Beijing Normal University, Beijing, China, 3 Centre for Complexity Science, Zeeman Building, University of Warwick, Coventry, United Kingdom, 4 US National Institutes of Health, Fogarty International Center, Bethesda, Maryland, United States of America, 5 Center for Disease Control and Prevention of Guizhou Province, GuiYang, China, 6 Center for Disease Control and Prevention of Shandong Province, Jinan, China
Abstract
Background
During the 2009 pandemic influenza H1N1 (2009) virus (pH1N1) outbreak, school students were at an increased risk of infection by the pH1N1 virus. However, the estimation of the attack rate showed significant variability.
Methods
Two school outbreaks were investigated in this study. A questionnaire was designed to collect information by interview. Throat samples were collected from all the subjects in this study 6 times and sero samples 3 times to confirm the infection and to determine viral shedding. Data analysis was performed using the software STATA 9.0.
Findings
The attack rate of the pH1N1 outbreak was 58.3% for the primary school, and 52.9% for the middle school. The asymptomatic infection rates of the two schools were 35.8% and 37.6% respectively. Peak virus shedding occurred on the day of ARI symptoms onset, followed by a steady decrease over subsequent days (p = 0.026). No difference was found either in viral shedding or HI titer between the symptomatic and the asymptomatic infectious groups.
Conclusions
School children were found to be at a high risk of infection by the novel virus. This may be because of a heightened risk of transmission owing to increased mixing at boarding school, or a lack of immunity owing to socio-economic status. We conclude that asymptomatically infectious cases may play an important role in transmission of the pH1N1 virus.
Citation: Yan L, Gao Y, Zhang Y, Tildesley M, Liu L, et al. (2012) Epidemiological and Virological Characteristics of Pandemic Influenza A (H1N1) School Outbreaks in China in 2009. PLoS ONE 7(9): e45898. doi:10.1371/journal.pone.0045898
Editor: Chiyu Zhang, Institut Pasteur of Shanghai, Chinese Academy of Sciences, China
Received: July 11, 2011; Accepted: August 23, 2012; Published: September 27, 2012
Copyright: ? 2012 Yan et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Funding: This study was supported by National Institutes of Health (NIH) Fund for the Special Program for Prevention and Control of Infectious Diseases (Grant No. 2008ZX10004-012), and NIH/NIAID Grant 5-U54-AI-057157-08 (Epidemiology and Molecular Mechanism of Highly Pathogenic Avian Influenza H5N1 and Pandemic Influenza H1N1). MT is supported by the Wellcome Trust, the RAPIDD program of the Science and Technology Directorate, Department of Homeland Security, and the Fogarty International Center, National Institutes of Health. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing interests: The authors have declared that no competing interests exist.
* E-mail: yshu@cnic.org.cn (YS); wangshiwencdc@163.com (SW)
# These authors contributed equally to this work.
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