Characteristics of hospitalized cases with influenza A (H1N1)pdm09 infection during first winter season of post-pandemic in China.
BACKGROUND: Influenza A (H1N1)pdm09 (2009 H1N1) re-circulated as the predominant virus from January through February 2011 in China. National surveillance of 2009 H1N1 as a notifiable disease was maintained to monitor potential changes in disease severity from the previous season. METHODOLOGY/PRINCIP...
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| Format: | Article |
| Language: | English |
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Public Library of Science (PLoS)
2013-01-01
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| Series: | PLoS ONE |
| Online Access: | http://europepmc.org/articles/PMC3564919?pdf=render |
| _version_ | 1818214396095102976 |
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| author | Cuiling Xu A Danielle Iuliano Min Chen Po-Yung Cheng Tao Chen Jinghong Shi Jing Yang Lijie Wang Fan Yuan Marc-Alain Widdowson Yuelong Shu |
| author_facet | Cuiling Xu A Danielle Iuliano Min Chen Po-Yung Cheng Tao Chen Jinghong Shi Jing Yang Lijie Wang Fan Yuan Marc-Alain Widdowson Yuelong Shu |
| author_sort | Cuiling Xu |
| collection | DOAJ |
| description | BACKGROUND: Influenza A (H1N1)pdm09 (2009 H1N1) re-circulated as the predominant virus from January through February 2011 in China. National surveillance of 2009 H1N1 as a notifiable disease was maintained to monitor potential changes in disease severity from the previous season. METHODOLOGY/PRINCIPAL FINDINGS: To describe the characteristics of hospitalized cases with 2009 H1N1 infection and analyze risk factors for severe illness during the 2010-2011winter season in China, we obtained surveillance data from hospitalized cases with 2009 H1N1 infection from November 2010 through May 2011, and reviewed medical records from 701 hospitalized cases. Age-standardized risk ratios were used to compare the age distribution of patients that were hospitalized and died due to 2009 H1N1 between the 2010-2011winter season to those during the 2009-2010 pandemic period. During the 2010-2011 winter season, children less than 5 years of age had the highest relative risk of hospitalization and death, followed by adults aged 65 years or older. Additionally, the relative risk of hospitalized cases aged 5-14 and 15-24 years was lower compared to children less than 5 years of age. During the winter season of 2010-2011, the proportions of adults aged 25 years or older for hospitalization and death were significantly higher than those during the 2009-2010 pandemic period. Being male, having a chronic medical condition, delayed hospital admission (≥3 days from onset) or delayed initiation of antiviral treatment (≥5 days from onset) were associated with severe illness among non-pregnant patients ≥2 years of age. CONCLUSIONS/SIGNIFICANCE: We observed a change in high risk groups for hospitalization for 2009 H1N1 during the winter months immediately following the pandemic period compared to the high risk groups identified during the pandemic period. Our nationally notifiable disease surveillance system enabled us to understand the evolving epidemiology of 2009 H1N1 infection after the pandemic period. |
| first_indexed | 2024-12-12T06:19:31Z |
| format | Article |
| id | doaj.art-5a84cc0f35254bb1b3abc90442c10b17 |
| institution | Directory Open Access Journal |
| issn | 1932-6203 |
| language | English |
| last_indexed | 2024-12-12T06:19:31Z |
| publishDate | 2013-01-01 |
| publisher | Public Library of Science (PLoS) |
| record_format | Article |
| series | PLoS ONE |
| spelling | doaj.art-5a84cc0f35254bb1b3abc90442c10b172022-12-22T00:34:56ZengPublic Library of Science (PLoS)PLoS ONE1932-62032013-01-0182e5501610.1371/journal.pone.0055016Characteristics of hospitalized cases with influenza A (H1N1)pdm09 infection during first winter season of post-pandemic in China.Cuiling XuA Danielle IulianoMin ChenPo-Yung ChengTao ChenJinghong ShiJing YangLijie WangFan YuanMarc-Alain WiddowsonYuelong ShuBACKGROUND: Influenza A (H1N1)pdm09 (2009 H1N1) re-circulated as the predominant virus from January through February 2011 in China. National surveillance of 2009 H1N1 as a notifiable disease was maintained to monitor potential changes in disease severity from the previous season. METHODOLOGY/PRINCIPAL FINDINGS: To describe the characteristics of hospitalized cases with 2009 H1N1 infection and analyze risk factors for severe illness during the 2010-2011winter season in China, we obtained surveillance data from hospitalized cases with 2009 H1N1 infection from November 2010 through May 2011, and reviewed medical records from 701 hospitalized cases. Age-standardized risk ratios were used to compare the age distribution of patients that were hospitalized and died due to 2009 H1N1 between the 2010-2011winter season to those during the 2009-2010 pandemic period. During the 2010-2011 winter season, children less than 5 years of age had the highest relative risk of hospitalization and death, followed by adults aged 65 years or older. Additionally, the relative risk of hospitalized cases aged 5-14 and 15-24 years was lower compared to children less than 5 years of age. During the winter season of 2010-2011, the proportions of adults aged 25 years or older for hospitalization and death were significantly higher than those during the 2009-2010 pandemic period. Being male, having a chronic medical condition, delayed hospital admission (≥3 days from onset) or delayed initiation of antiviral treatment (≥5 days from onset) were associated with severe illness among non-pregnant patients ≥2 years of age. CONCLUSIONS/SIGNIFICANCE: We observed a change in high risk groups for hospitalization for 2009 H1N1 during the winter months immediately following the pandemic period compared to the high risk groups identified during the pandemic period. Our nationally notifiable disease surveillance system enabled us to understand the evolving epidemiology of 2009 H1N1 infection after the pandemic period.http://europepmc.org/articles/PMC3564919?pdf=render |
| spellingShingle | Cuiling Xu A Danielle Iuliano Min Chen Po-Yung Cheng Tao Chen Jinghong Shi Jing Yang Lijie Wang Fan Yuan Marc-Alain Widdowson Yuelong Shu Characteristics of hospitalized cases with influenza A (H1N1)pdm09 infection during first winter season of post-pandemic in China. PLoS ONE |
| title | Characteristics of hospitalized cases with influenza A (H1N1)pdm09 infection during first winter season of post-pandemic in China. |
| title_full | Characteristics of hospitalized cases with influenza A (H1N1)pdm09 infection during first winter season of post-pandemic in China. |
| title_fullStr | Characteristics of hospitalized cases with influenza A (H1N1)pdm09 infection during first winter season of post-pandemic in China. |
| title_full_unstemmed | Characteristics of hospitalized cases with influenza A (H1N1)pdm09 infection during first winter season of post-pandemic in China. |
| title_short | Characteristics of hospitalized cases with influenza A (H1N1)pdm09 infection during first winter season of post-pandemic in China. |
| title_sort | characteristics of hospitalized cases with influenza a h1n1 pdm09 infection during first winter season of post pandemic in china |
| url | http://europepmc.org/articles/PMC3564919?pdf=render |
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