File Download

Conference Paper: Mild to moderate influenza A(H7N9) infections detected through China’s national influenza-like Illness sentinel surveillance system

TitleMild to moderate influenza A(H7N9) infections detected through China’s national influenza-like Illness sentinel surveillance system
Authors
Issue Date2013
PublisherInternational Society for Influenza and other Respiratory Virus Diseases (ISIRV). The Conference Abstracts' web site is located at: http://optionsviii.controlinfluenza.com/optionsviii/assets/File/Options_VIII_Abstracts_2013.pdf
Citation
The 2013 International Scientific Conference of Options for the Control of Influenza (Options-8), Cape Town, South Africa, 5-10 September 2013. In Conference Abstracts, 2013, p. 20-21, abstract no. P1-116 How to Cite?
AbstractBackground: The “clinical iceberg” phenomenon, where there are usually many more infected cases than is apparent symptomatically and even less so registered in the clinical setting, is a common feature of influenza disease. While this is certainly true for interpandemic influenza and the 2009 influenza A(H1N1) pandemic, this appeared to be less substantial for the Dutch A(H7N7) outbreak, and with A(H5N1) being an acknowledged exception. It remains unknown whether the “iceberg” applies to the influenza A(H7N9) virus that emerged in early 2013 in China. While the majority of laboratory-confirmed A(H7N9) cases presented with a severe clinical picture to a hospital, a small number of laboratory-confirmed cases have been identified through the sentinel influenza-like illness (ILI) surveillance system nationwide. The objective of our study was to describe the clinical characteristics of the complete case series of A(H7N9) cases as of May 15, 2013, that were identified through routine testing by the ILI sentinel surveillance system. Materials and Methods: ILI sentinel surveillance in China is conducted through a network of 554 hospitals across the country, with the total number of outpatient and/or emergency department visits and the number of patients fitting the WHO standard ILI case definition reported weekly online to the China CDC, and 10-15 nasopharyngeal swabs collected from ILI patients each week for routine laboratory testing and subtyping. All A(H7N9) cases detected through the ILI surveillance system by May 15, 2013, were identified by cross-referencing the laboratory-confirmed A(H7N9) line list with the routine sentinel ILI surveillance system. Demographic and epidemiologic data were extracted from field investigation records, and clinical and laboratory data were obtained from medical chart review. Results: Five (3.8%) of a total of 130 laboratory-confirmed influenza A(H7N9) cases reported as of May 28, 2013, were detected through the routine ILI surveillance system. Four (80%) of them were male. Mean age was 13 (range = 2-26) years and none had any underlying medical condition. Exposure history, geographic location and timing of symptom onset were otherwise similar to the general cohort of all laboratory-confirmed cases to date. All patients experienced only mild or moderate disease with an uneventful course of recovery. Among them three (60%) were managed only as outpatients and all quickly recovered after 3-5 days, with nasopharyngeal swabs tested positive for A(H7N9) only after their full recovery. Two patients (40%) were hospitalized for treatment. One was a 4-year-old child from Shanghai who presented initially as an outpatient with fever and mild rhinorrhea to a routine sentinel clinic, and was admitted on the next day for oseltamivir treatment after his nasopharyngeal swab was tested positive for A(H7N9). The other was a 26-year-old man from Jiangsu who presented initially with fever and productive cough to a sentinel clinic, being given ceftazidime without improvement. He was admitted 4 days later with radiologic evidence of left-sided pneumonia, and started on oseltamivir and moxifloxacin. Both remained clinically stable with quick resolution of symptoms within 10 days. Conclusions: Our complete case series of A(H7N9) cases detected through the routine ILI surveillance system provide contrasting clinical presentations to the generally much more severe clinical picture of the majority of laboratory-confirmed A(H7N9) cases detected otherwise. Our findings provide indirect evidence of a substantial proportion of mild disease and support the existence of a “clinical iceberg” phenomenon in influenza A(H7N9) infections. For the clinician, our findings reinforce vigilance to the diverse presentation that can be associated with influenza A(H7N9) virus infections. Our results also suggest that large-scale community surveillance networks can be useful as a population-based sampling tool to enhance understanding of the full spectrum of disease, especially in the early phase of an evolving epidemic.
DescriptionPoster Session: News and Views from the H7N9 Outbreak
Persistent Identifierhttp://hdl.handle.net/10722/202064

 

DC FieldValueLanguage
dc.contributor.authorIp, DKMen_US
dc.contributor.authorLiao, QHen_US
dc.contributor.authorWu, Pen_US
dc.contributor.authorGao, Zen_US
dc.contributor.authorCao, Ben_US
dc.contributor.authorFeng, Len_US
dc.contributor.authorXu, Xen_US
dc.contributor.authorJiang, Hen_US
dc.contributor.authorLi, Men_US
dc.contributor.authorBao, Jen_US
dc.contributor.authorZheng, Jen_US
dc.contributor.authorZhang, Qen_US
dc.contributor.authorChang, ZCen_US
dc.contributor.authorLi, Yen_US
dc.contributor.authorYu, Jen_US
dc.contributor.authorLiu, Fen_US
dc.contributor.authorWu, JTKen_US
dc.contributor.authorCowling, BJen_US
dc.contributor.authorYang, Wen_US
dc.contributor.authorLeung, GMen_US
dc.contributor.authorYu, Hen_US
dc.date.accessioned2014-08-21T08:01:23Z-
dc.date.available2014-08-21T08:01:23Z-
dc.date.issued2013en_US
dc.identifier.citationThe 2013 International Scientific Conference of Options for the Control of Influenza (Options-8), Cape Town, South Africa, 5-10 September 2013. In Conference Abstracts, 2013, p. 20-21, abstract no. P1-116en_US
dc.identifier.urihttp://hdl.handle.net/10722/202064-
dc.descriptionPoster Session: News and Views from the H7N9 Outbreak-
dc.description.abstractBackground: The “clinical iceberg” phenomenon, where there are usually many more infected cases than is apparent symptomatically and even less so registered in the clinical setting, is a common feature of influenza disease. While this is certainly true for interpandemic influenza and the 2009 influenza A(H1N1) pandemic, this appeared to be less substantial for the Dutch A(H7N7) outbreak, and with A(H5N1) being an acknowledged exception. It remains unknown whether the “iceberg” applies to the influenza A(H7N9) virus that emerged in early 2013 in China. While the majority of laboratory-confirmed A(H7N9) cases presented with a severe clinical picture to a hospital, a small number of laboratory-confirmed cases have been identified through the sentinel influenza-like illness (ILI) surveillance system nationwide. The objective of our study was to describe the clinical characteristics of the complete case series of A(H7N9) cases as of May 15, 2013, that were identified through routine testing by the ILI sentinel surveillance system. Materials and Methods: ILI sentinel surveillance in China is conducted through a network of 554 hospitals across the country, with the total number of outpatient and/or emergency department visits and the number of patients fitting the WHO standard ILI case definition reported weekly online to the China CDC, and 10-15 nasopharyngeal swabs collected from ILI patients each week for routine laboratory testing and subtyping. All A(H7N9) cases detected through the ILI surveillance system by May 15, 2013, were identified by cross-referencing the laboratory-confirmed A(H7N9) line list with the routine sentinel ILI surveillance system. Demographic and epidemiologic data were extracted from field investigation records, and clinical and laboratory data were obtained from medical chart review. Results: Five (3.8%) of a total of 130 laboratory-confirmed influenza A(H7N9) cases reported as of May 28, 2013, were detected through the routine ILI surveillance system. Four (80%) of them were male. Mean age was 13 (range = 2-26) years and none had any underlying medical condition. Exposure history, geographic location and timing of symptom onset were otherwise similar to the general cohort of all laboratory-confirmed cases to date. All patients experienced only mild or moderate disease with an uneventful course of recovery. Among them three (60%) were managed only as outpatients and all quickly recovered after 3-5 days, with nasopharyngeal swabs tested positive for A(H7N9) only after their full recovery. Two patients (40%) were hospitalized for treatment. One was a 4-year-old child from Shanghai who presented initially as an outpatient with fever and mild rhinorrhea to a routine sentinel clinic, and was admitted on the next day for oseltamivir treatment after his nasopharyngeal swab was tested positive for A(H7N9). The other was a 26-year-old man from Jiangsu who presented initially with fever and productive cough to a sentinel clinic, being given ceftazidime without improvement. He was admitted 4 days later with radiologic evidence of left-sided pneumonia, and started on oseltamivir and moxifloxacin. Both remained clinically stable with quick resolution of symptoms within 10 days. Conclusions: Our complete case series of A(H7N9) cases detected through the routine ILI surveillance system provide contrasting clinical presentations to the generally much more severe clinical picture of the majority of laboratory-confirmed A(H7N9) cases detected otherwise. Our findings provide indirect evidence of a substantial proportion of mild disease and support the existence of a “clinical iceberg” phenomenon in influenza A(H7N9) infections. For the clinician, our findings reinforce vigilance to the diverse presentation that can be associated with influenza A(H7N9) virus infections. Our results also suggest that large-scale community surveillance networks can be useful as a population-based sampling tool to enhance understanding of the full spectrum of disease, especially in the early phase of an evolving epidemic.-
dc.languageengen_US
dc.publisherInternational Society for Influenza and other Respiratory Virus Diseases (ISIRV). The Conference Abstracts' web site is located at: http://optionsviii.controlinfluenza.com/optionsviii/assets/File/Options_VIII_Abstracts_2013.pdfen_US
dc.relation.ispartofInternational Scientific Conference of Options for the Control of Influenza, Options-8en_US
dc.rightsCreative Commons: Attribution 3.0 Hong Kong License-
dc.titleMild to moderate influenza A(H7N9) infections detected through China’s national influenza-like Illness sentinel surveillance systemen_US
dc.typeConference_Paperen_US
dc.identifier.emailIp, DKM: dkmip@hku.hken_US
dc.identifier.emailWu, P: pengwu@hku.hken_US
dc.identifier.emailWu, JTK: joewu@hku.hken_US
dc.identifier.emailCowling, BJ: bcowling@hku.hken_US
dc.identifier.emailLeung, GM: gmleung@hku.hken_US
dc.identifier.authorityIp, DKM=rp00256en_US
dc.identifier.authorityWu, JTK=rp00517en_US
dc.identifier.authorityCowling, BJ=rp01326en_US
dc.identifier.authorityLeung, GM=rp00460en_US
dc.description.naturepublished_or_final_version-
dc.identifier.hkuros233340en_US
dc.identifier.spage20, abstract no. P1-116-
dc.identifier.epage21, abstract no. P1-116-
dc.publisher.placeUnited Kingdom-

Export via OAI-PMH Interface in XML Formats


OR


Export to Other Non-XML Formats