1
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Chen X, Wang W, Wang Y, Lai S, Yang J, Cowling BJ, Horby PW, Uyeki TM, Yu H. Serological evidence of human infections with highly pathogenic avian influenza A(H5N1) virus: a systematic review and meta-analysis. BMC Med 2020; 18:377. [PMID: 33261599 PMCID: PMC7709391 DOI: 10.1186/s12916-020-01836-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 11/02/2020] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND Highly pathogenic avian influenza A(H5N1) virus poses a global public health threat given severe and fatal zoonotic infections since 1997 and ongoing A(H5N1) virus circulation among poultry in several countries. A comprehensive assessment of the seroprevalence of A(H5N1) virus antibodies remains a gap and limits understanding of the true risk of A(H5N1) virus infection. METHODS We conducted a systematic review and meta-analysis of published serosurveys to assess the risk of subclinical and clinically mild A(H5N1) virus infections. We assessed A(H5N1) virus antibody titers and changes in titers among populations with variable exposures to different A(H5N1) viruses. RESULTS Across studies using the World Health Organization-recommended seropositive definition, the point estimates of the seroprevalence of A(H5N1) virus-specific antibodies were higher in poultry-exposed populations (range 0-0.6%) and persons exposed to both human A(H5N1) cases and infected birds (range 0.4-1.8%) than in close contacts of A(H5N1) cases or the general population (none to very low frequencies). Seroprevalence was higher in persons exposed to A(H5N1) clade 0 virus (1.9%, range 0.7-3.2%) than in participants exposed to other clades of A(H5N1) virus (range 0-0.5%) (p < 0.05). Seroprevalence was higher in poultry-exposed populations (range 0-1.9%) if such studies utilized antigenically similar A(H5N1) virus antigens in assays to A(H5N1) viruses circulating among poultry. CONCLUSIONS These low seroprevalences suggest that subclinical and clinically mild human A(H5N1) virus infections are uncommon. Standardized serological survey and laboratory methods are needed to fully understand the extent and risk of human A(H5N1) virus infections.
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Affiliation(s)
- Xinhua Chen
- School of Public Health, Fudan University, Key Laboratory of Public Health Safety, Ministry of Education, Shanghai, 200032, China
| | - Wei Wang
- School of Public Health, Fudan University, Key Laboratory of Public Health Safety, Ministry of Education, Shanghai, 200032, China
| | - Yan Wang
- School of Public Health, Fudan University, Key Laboratory of Public Health Safety, Ministry of Education, Shanghai, 200032, China
| | - Shengjie Lai
- School of Public Health, Fudan University, Key Laboratory of Public Health Safety, Ministry of Education, Shanghai, 200032, China
- WorldPop, School of Geography and Environmental Science, University of Southampton, Southampton, SO17 1BJ, UK
| | - Juan Yang
- School of Public Health, Fudan University, Key Laboratory of Public Health Safety, Ministry of Education, Shanghai, 200032, China
| | - Benjamin J Cowling
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, Special Administrative Region, China
| | - Peter W Horby
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, UK
| | - Timothy M Uyeki
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, USA
| | - Hongjie Yu
- School of Public Health, Fudan University, Key Laboratory of Public Health Safety, Ministry of Education, Shanghai, 200032, China.
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2
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Qi Y, Ni HB, Chen X, Li S. Seroprevalence of highly pathogenic avian influenza (H5N1) virus infection among humans in mainland China: A systematic review and meta-analysis. Transbound Emerg Dis 2020; 67:1861-1871. [PMID: 32259345 DOI: 10.1111/tbed.13564] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 03/21/2020] [Accepted: 03/23/2020] [Indexed: 12/28/2022]
Abstract
Although the effective transmission of the H5N1 virus from humans to humans has yet to be further observed, humans are at increased risk of a pandemic caused by H5N1. In order to fully evaluate the seroprevalence and risk factor of highly pathogenic avian influenza A (H5N1) virus infection among in mainland China, we performed a systematic review and meta-analysis. In this review, we searched literature on the seroprevalence of H5N1 infection among humans in mainland China from 1 January 1997 to 20 October 2018 in English and Chinese databases, including PubMed, Google scholar, Cochrane library, Clinical Trial, VIP, CNKI and WanFang database. We made a selection according to the title and the abstract of paper, and then, we excluded duplicated literature, and data incomplete literature according to the exclusion criteria we formulated. Finally, we extracted how many humans have H5N1 infection from the obtained studies to establish the seroprevalence of H5N1 infection among humans in mainland China. A total of 56 studies (including data of 35,159 humans) were compliant with our criteria. In China, the overall seroprevalence of H5N1 infection among humans was 2.45% (862/35,159), while the seroprevalence of H5N1 infection among humans from central China was 7.32% (213/2,911), higher than those in other regions of China. The seroprevalence of H5N1 infection was associated with test method, sampling time and demographic characteristics of humans. However, there was no significant difference in the effect of gender on the seroprevalence of H5N1 among humans in China. The purpose of this review was to better understand the real infection rate of H5N1 virus among humans and evaluate the potential risk factors for the zoonotic spread of H5N1 virus to humans. Sufficient epidemiological data are important to explore and understand the prevalent status of AIVs throughout the country and to disease control.
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Affiliation(s)
- Yanping Qi
- College of Animal Science, Anhui Province Key Laboratory of Animal nutritional regulation and health, Anhui Science and Technology University, Fengyang, China
| | - Hong-Bo Ni
- College of Veterinary Medicine, Qingdao Agricultural University, Qingdao, China
| | - Xuelong Chen
- College of Animal Science, Anhui Province Key Laboratory of Animal nutritional regulation and health, Anhui Science and Technology University, Fengyang, China
| | - Shenghe Li
- College of Animal Science, Anhui Province Key Laboratory of Animal nutritional regulation and health, Anhui Science and Technology University, Fengyang, China
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3
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de Bruin E, Zhang X, Ke C, Sikkema R, Koopmans M. Serological evidence for exposure to avian influenza viruses within poultry workers in southern China. Zoonoses Public Health 2017; 64:e51-e59. [PMID: 28220658 DOI: 10.1111/zph.12346] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Indexed: 01/20/2023]
Abstract
The risk of infection with avian influenza viruses for poultry workers is relatively unknown in China, and study results are often biased by the notification of only the severe human cases. Protein microarray was used to detect binding antibodies to 13 different haemagglutinin (HA1-part) antigens of avian influenza A(H5N1), A(H7N7), A(H7N9) and A(H9N2) viruses, in serum samples from poultry workers and healthy blood donors collected in the course of 3 years in Guangdong Province, China. Significantly higher antibody titre levels were detected in poultry workers when compared to blood donors for the most recent H5 and H9 strains tested. These differences were most pronounced in younger age groups for antigens from older strains, but were observed in all age groups for the recent H5 and H9 antigens. For the H7 strains tested, only poultry workers from two retail live poultry markets had significantly higher antibody titres compared to blood donors.
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Affiliation(s)
- E de Bruin
- Department of Viroscience, Erasmus Medical Center, Rotterdam, The Netherlands.,Laboratory for Infectious Diseases and Perinatal Screening, Center for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
| | - X Zhang
- Guangdong Province Center for Disease Control and Prevention, Panyu District, Guangzhou, Guangdong, China
| | - C Ke
- Guangdong Province Center for Disease Control and Prevention, Panyu District, Guangzhou, Guangdong, China
| | - R Sikkema
- Department of Viroscience, Erasmus Medical Center, Rotterdam, The Netherlands.,Laboratory for Infectious Diseases and Perinatal Screening, Center for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
| | - M Koopmans
- Department of Viroscience, Erasmus Medical Center, Rotterdam, The Netherlands.,Laboratory for Infectious Diseases and Perinatal Screening, Center for Infectious Disease Control, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands
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4
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Lipsitch M, Barclay W, Raman R, Russell CJ, Belser JA, Cobey S, Kasson PM, Lloyd-Smith JO, Maurer-Stroh S, Riley S, Beauchemin CA, Bedford T, Friedrich TC, Handel A, Herfst S, Murcia PR, Roche B, Wilke CO, Russell CA. Viral factors in influenza pandemic risk assessment. eLife 2016; 5. [PMID: 27834632 PMCID: PMC5156527 DOI: 10.7554/elife.18491] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 11/03/2016] [Indexed: 12/13/2022] Open
Abstract
The threat of an influenza A virus pandemic stems from continual virus spillovers from reservoir species, a tiny fraction of which spark sustained transmission in humans. To date, no pandemic emergence of a new influenza strain has been preceded by detection of a closely related precursor in an animal or human. Nonetheless, influenza surveillance efforts are expanding, prompting a need for tools to assess the pandemic risk posed by a detected virus. The goal would be to use genetic sequence and/or biological assays of viral traits to identify those non-human influenza viruses with the greatest risk of evolving into pandemic threats, and/or to understand drivers of such evolution, to prioritize pandemic prevention or response measures. We describe such efforts, identify progress and ongoing challenges, and discuss three specific traits of influenza viruses (hemagglutinin receptor binding specificity, hemagglutinin pH of activation, and polymerase complex efficiency) that contribute to pandemic risk.
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Affiliation(s)
- Marc Lipsitch
- Center for Communicable Disease Dynamics, Harvard T. H Chan School of Public Health, Boston, United States.,Department of Epidemiology, Harvard T. H. Chan School of Public Health, Boston, United States.,Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, United States
| | - Wendy Barclay
- Division of Infectious Disease, Faculty of Medicine, Imperial College, London, United Kingdom
| | - Rahul Raman
- Department of Biological Engineering, Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, United States
| | - Charles J Russell
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, United States
| | - Jessica A Belser
- Centers for Disease Control and Prevention, Atlanta, United States
| | - Sarah Cobey
- Department of Ecology and Evolutionary Biology, University of Chicago, Chicago, United States
| | - Peter M Kasson
- Department of Biomedical Engineering, University of Virginia, Charlottesville, United States.,Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, United States
| | - James O Lloyd-Smith
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, United States.,Fogarty International Center, National Institutes of Health, Bethesda, United States
| | - Sebastian Maurer-Stroh
- Bioinformatics Institute, Agency for Science Technology and Research, Singapore, Singapore.,National Public Health Laboratory, Communicable Diseases Division, Ministry of Health, Singapore, Singapore.,School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Steven Riley
- MRC Centre for Outbreak Analysis and Modelling, School of Public Health, Imperial College London, London, United Kingdom.,Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, London, United Kingdom
| | | | - Trevor Bedford
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, United States
| | - Thomas C Friedrich
- Department of Pathobiological Sciences, University of Wisconsin School of Veterinary Medicine, Madison, United States
| | - Andreas Handel
- Department of Epidemiology and Biostatistics, College of Public Health, University of Georgia, Athens, United States
| | - Sander Herfst
- Department of Viroscience, Erasmus Medical Center, Rotterdam, Netherlands
| | - Pablo R Murcia
- MRC-University of Glasgow Centre For Virus Research, Glasgow, United Kingdom
| | | | - Claus O Wilke
- Center for Computational Biology and Bioinformatics, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, United States.,Department of Integrative Biology, The University of Texas at Austin, Austin, United States
| | - Colin A Russell
- Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom
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5
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Shimizu K, Wulandari L, Poetranto ED, Setyoningrum RA, Yudhawati R, Sholikhah A, Nastri AM, Poetranto AL, Candra AYR, Puruhito EF, Takahara Y, Yamagishi Y, Yamaoka M, Hotta H, Ustumi T, Lusida MI, Soetjipto, Shimizu YK, Soegiarto G, Mori Y. Seroevidence for a High Prevalence of Subclinical Infection With Avian Influenza A(H5N1) Virus Among Workers in a Live-Poultry Market in Indonesia. J Infect Dis 2016; 214:1929-1936. [PMID: 27923953 PMCID: PMC5142092 DOI: 10.1093/infdis/jiw478] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 10/03/2016] [Indexed: 02/02/2023] Open
Abstract
Background. In Indonesia, highly pathogenic avian influenza A(H5N1) virus has become endemic in poultry and has caused sporadic deadly infections in human. Since 2012, we have conducted fixed-point surveillance of avian influenza viruses at a live-poultry market in East Java, Indonesia. In this study, we examined the seroprevalence of avian influenza A(H5N1) virus infection among market workers. Methods. Sera were collected from 101 workers in early 2014 and examined for antibody activity against avian A(H5N1) Eurasian lineage virus by a hemagglutination-inhibition (HI) assay. Results. By the HI assay, 84% of the sera tested positive for antibody activity against the avian virus. Further analysis revealed that the average HI titer in 2014 was 2.9-fold higher than in 2012 and that seroconversion occurred in 44% of paired sera (11 of 25) between 2012 and 2014. A medical history survey was performed in 2016; responses to questionnaires indicated that none of workers had had severe acute respiratory illness during 2013. Conclusions. This study provides evidence of a high prevalence of avian A(H5N1) virus infection in 2013 among workers at a live-poultry market. However, because no instances of hospitalizations were reported, we can conclude the virus did not manifest any clinical symptoms in workers.
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Affiliation(s)
- Kazufumi Shimizu
- Indonesia-Japan Collaborative Research Center for Emerging and Re-emerging Infectious Diseases, Institute of Tropical Disease.,Center for Infectious Diseases, Kobe University Graduate School of Medicine, Japan
| | - Laksmi Wulandari
- Indonesia-Japan Collaborative Research Center for Emerging and Re-emerging Infectious Diseases, Institute of Tropical Disease.,Department of Pulmonology and Respiratory Medicine
| | - Emmanuel D Poetranto
- Indonesia-Japan Collaborative Research Center for Emerging and Re-emerging Infectious Diseases, Institute of Tropical Disease.,Department of Clinical Science, Faculty of Veterinary Medicine, Airlangga University, Surabaya, Indonesia
| | - Retno A Setyoningrum
- Indonesia-Japan Collaborative Research Center for Emerging and Re-emerging Infectious Diseases, Institute of Tropical Disease.,Department of Pediatrics
| | - Resti Yudhawati
- Indonesia-Japan Collaborative Research Center for Emerging and Re-emerging Infectious Diseases, Institute of Tropical Disease.,Department of Pulmonology and Respiratory Medicine
| | - Amelia Sholikhah
- Indonesia-Japan Collaborative Research Center for Emerging and Re-emerging Infectious Diseases, Institute of Tropical Disease.,Department of Pediatrics
| | - Aldise M Nastri
- Indonesia-Japan Collaborative Research Center for Emerging and Re-emerging Infectious Diseases, Institute of Tropical Disease
| | - Anna L Poetranto
- Indonesia-Japan Collaborative Research Center for Emerging and Re-emerging Infectious Diseases, Institute of Tropical Disease
| | - Adithya Y R Candra
- Indonesia-Japan Collaborative Research Center for Emerging and Re-emerging Infectious Diseases, Institute of Tropical Disease
| | - Edith F Puruhito
- Indonesia-Japan Collaborative Research Center for Emerging and Re-emerging Infectious Diseases, Institute of Tropical Disease
| | - Yusuke Takahara
- Indonesia-Japan Collaborative Research Center for Emerging and Re-emerging Infectious Diseases, Institute of Tropical Disease.,Center for Infectious Diseases, Kobe University Graduate School of Medicine, Japan
| | - Yoshiaki Yamagishi
- Indonesia-Japan Collaborative Research Center for Emerging and Re-emerging Infectious Diseases, Institute of Tropical Disease.,Center for Infectious Diseases, Kobe University Graduate School of Medicine, Japan
| | - Masaoki Yamaoka
- Indonesia-Japan Collaborative Research Center for Emerging and Re-emerging Infectious Diseases, Institute of Tropical Disease.,Center for Infectious Diseases, Kobe University Graduate School of Medicine, Japan
| | - Hak Hotta
- Center for Infectious Diseases, Kobe University Graduate School of Medicine, Japan
| | - Takako Ustumi
- Indonesia-Japan Collaborative Research Center for Emerging and Re-emerging Infectious Diseases, Institute of Tropical Disease.,Center for Infectious Diseases, Kobe University Graduate School of Medicine, Japan
| | - Maria I Lusida
- Indonesia-Japan Collaborative Research Center for Emerging and Re-emerging Infectious Diseases, Institute of Tropical Disease
| | - Soetjipto
- Indonesia-Japan Collaborative Research Center for Emerging and Re-emerging Infectious Diseases, Institute of Tropical Disease
| | - Yohko K Shimizu
- Indonesia-Japan Collaborative Research Center for Emerging and Re-emerging Infectious Diseases, Institute of Tropical Disease.,Center for Infectious Diseases, Kobe University Graduate School of Medicine, Japan
| | - Gatot Soegiarto
- Indonesia-Japan Collaborative Research Center for Emerging and Re-emerging Infectious Diseases, Institute of Tropical Disease.,Department of Internal Medicine, Faculty of Medicine
| | - Yasuko Mori
- Center for Infectious Diseases, Kobe University Graduate School of Medicine, Japan
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6
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Freidl GS, van den Ham HJ, Boni MF, de Bruin E, Koopmans MPG. Changes in heterosubtypic antibody responses during the first year of the 2009 A(H1N1) influenza pandemic. Sci Rep 2016; 6:20385. [PMID: 26853924 PMCID: PMC4745054 DOI: 10.1038/srep20385] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 12/31/2015] [Indexed: 12/20/2022] Open
Abstract
Seropositivity to avian influenza (AI) via low-level antibody titers has been reported in the general population and poultry-exposed individuals, raising the question whether these findings reflect true infection with AI or cross-reactivity. Here we investigated serological profiles against human and avian influenza viruses in the general population using a protein microarray platform. We hypothesized that higher antibody diversity across recent H1 and H3 influenza viruses would be associated with heterosubtypic reactivity to older pandemic- and AI viruses. We found significant heterogeneity in antibody profiles. Increased antibody diversity to seasonal influenza viruses was associated with low-level heterosubtypic antibodies to H9 and H7, but not to H5 AI virus. Individuals exposed to the recent 2009 A(H1N1) pandemic showed higher heterosubtypic reactivity. We show that there is a complex interplay between prior exposures to seasonal and recent pandemic influenza viruses and the development of heterosubtypic antibody reactivity to animal influenza viruses.
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Affiliation(s)
- Gudrun S Freidl
- Viroscience Department, Erasmus Medical Center, Rotterdam, the Netherlands.,Virology Department, Centre for Infectious Diseases Research, Diagnostics and Screening, National Institute for Public Health and the Environment, Bilthoven, the Netherlands
| | | | - Maciej F Boni
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Vietnam.,Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Erwin de Bruin
- Viroscience Department, Erasmus Medical Center, Rotterdam, the Netherlands.,Virology Department, Centre for Infectious Diseases Research, Diagnostics and Screening, National Institute for Public Health and the Environment, Bilthoven, the Netherlands
| | - Marion P G Koopmans
- Viroscience Department, Erasmus Medical Center, Rotterdam, the Netherlands.,Virology Department, Centre for Infectious Diseases Research, Diagnostics and Screening, National Institute for Public Health and the Environment, Bilthoven, the Netherlands
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7
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Riley P, Ben-Nun M, Linker JA, Cost AA, Sanchez JL, George D, Bacon DP, Riley S. Early Characterization of the Severity and Transmissibility of Pandemic Influenza Using Clinical Episode Data from Multiple Populations. PLoS Comput Biol 2015; 11:e1004392. [PMID: 26402446 PMCID: PMC4581836 DOI: 10.1371/journal.pcbi.1004392] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 06/09/2015] [Indexed: 11/25/2022] Open
Abstract
The potential rapid availability of large-scale clinical episode data during the next influenza pandemic suggests an opportunity for increasing the speed with which novel respiratory pathogens can be characterized. Key intervention decisions will be determined by both the transmissibility of the novel strain (measured by the basic reproductive number R0) and its individual-level severity. The 2009 pandemic illustrated that estimating individual-level severity, as described by the proportion pC of infections that result in clinical cases, can remain uncertain for a prolonged period of time. Here, we use 50 distinct US military populations during 2009 as a retrospective cohort to test the hypothesis that real-time encounter data combined with disease dynamic models can be used to bridge this uncertainty gap. Effectively, we estimated the total number of infections in multiple early-affected communities using the model and divided that number by the known number of clinical cases. Joint estimates of severity and transmissibility clustered within a relatively small region of parameter space, with 40 of the 50 populations bounded by: pC, 0.0133-0.150 and R0, 1.09-2.16. These fits were obtained despite widely varying incidence profiles: some with spring waves, some with fall waves and some with both. To illustrate the benefit of specific pairing of rapidly available data and infectious disease models, we simulated a future moderate pandemic strain with pC approximately ×10 that of 2009; the results demonstrating that even before the peak had passed in the first affected population, R0 and pC could be well estimated. This study provides a clear reference in this two-dimensional space against which future novel respiratory pathogens can be rapidly assessed and compared with previous pandemics.
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Affiliation(s)
- Pete Riley
- Predictive Science Inc., San Diego, California, United States of America
| | - Michal Ben-Nun
- Predictive Science Inc., San Diego, California, United States of America
| | - Jon A. Linker
- Predictive Science Inc., San Diego, California, United States of America
| | - Angelia A. Cost
- Armed Forces Health Surveillance Center, Silver Spring, Maryland, United States of America
| | - Jose L. Sanchez
- Armed Forces Health Surveillance Center, Silver Spring, Maryland, United States of America
| | - Dylan George
- Biomedical Advanced Research and Development Authority (BARDA), Assistant Secretary for Preparedness and Response (ASPR), Department of Health and Human Services (HHS), Washington, D.C., United States of America
| | | | - Steven Riley
- Predictive Science Inc., San Diego, California, United States of America
- MRC Centre for Outbreak Analysis and Modelling, Imperial College London, United Kingdom
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8
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Lipsitch M, Donnelly CA, Fraser C, Blake IM, Cori A, Dorigatti I, Ferguson NM, Garske T, Mills HL, Riley S, Van Kerkhove MD, Hernán MA. Potential Biases in Estimating Absolute and Relative Case-Fatality Risks during Outbreaks. PLoS Negl Trop Dis 2015; 9:e0003846. [PMID: 26181387 PMCID: PMC4504518 DOI: 10.1371/journal.pntd.0003846] [Citation(s) in RCA: 124] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Estimating the case-fatality risk (CFR)-the probability that a person dies from an infection given that they are a case-is a high priority in epidemiologic investigation of newly emerging infectious diseases and sometimes in new outbreaks of known infectious diseases. The data available to estimate the overall CFR are often gathered for other purposes (e.g., surveillance) in challenging circumstances. We describe two forms of bias that may affect the estimation of the overall CFR-preferential ascertainment of severe cases and bias from reporting delays-and review solutions that have been proposed and implemented in past epidemics. Also of interest is the estimation of the causal impact of specific interventions (e.g., hospitalization, or hospitalization at a particular hospital) on survival, which can be estimated as a relative CFR for two or more groups. When observational data are used for this purpose, three more sources of bias may arise: confounding, survivorship bias, and selection due to preferential inclusion in surveillance datasets of those who are hospitalized and/or die. We illustrate these biases and caution against causal interpretation of differential CFR among those receiving different interventions in observational datasets. Again, we discuss ways to reduce these biases, particularly by estimating outcomes in smaller but more systematically defined cohorts ascertained before the onset of symptoms, such as those identified by forward contact tracing. Finally, we discuss the circumstances in which these biases may affect non-causal interpretation of risk factors for death among cases.
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Affiliation(s)
- Marc Lipsitch
- Center for Communicable Disease Dynamics, Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, United States of America
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, United States of America
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
- * E-mail:
| | - Christl A. Donnelly
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Christophe Fraser
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Isobel M. Blake
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Anne Cori
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Ilaria Dorigatti
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Neil M. Ferguson
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Tini Garske
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Harriet L. Mills
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Steven Riley
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
| | - Maria D. Van Kerkhove
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, United Kingdom
- Centre for Global Health, Institut Pasteur, Paris, France
| | - Miguel A. Hernán
- Center for Communicable Disease Dynamics, Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, United States of America
- Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, United States of America
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9
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El Rifay AS, Elabd MA, Abu Zeid D, Gomaa MR, Tang L, McKenzie PP, Webby RJ, Ali MA, Kayali G. Household Transmission of Zoonotic Influenza Viruses in a Cohort of Egyptian Poultry Growers. JMIR Res Protoc 2015; 4:e74. [PMID: 26099368 PMCID: PMC4526956 DOI: 10.2196/resprot.4331] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Revised: 04/23/2015] [Accepted: 04/23/2015] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND The highly pathogenic avian influenza H5N1 viruses and the low pathogenic H9N2 viruses are enzootic in Egyptian poultry. Several cases of human infection with H5N1 were reported in Egypt. We previously determined that the seroprevalence of H5N1 antibodies in Egyptians exposed to poultry is 2.1% (15/708), suggesting that mild or subclinical infections with this virus occur. We aim to measure the incidence of avian influenza infection in Egyptians exposed to poultry, study risk factors of infection, study the resulting immune response, study household transmission rates, and characterize the viruses causing infections. OBJECTIVE The objective of the study is to design a 7-year, prospective, household-based cohort investigation to determine incidence and household transmission of avian influenza viruses in humans exposed to poultry. METHODS At baseline, we will collect sera to measure antibodies against influenza A. Field nurses will visit enrolled subjects at least weekly to check for influenza-like illness symptoms and verify influenza infection by a point of care rapid test. From subjects with influenza infection and their household contacts, we will collect nasal swabs, throat swabs, and nasal washes to characterize the antigenic and genetic makeup of influenza viruses infecting humans. The nurse will also obtain 2x 3-ml blood samples, one for serology, and another for isolating peripheral blood mononuclear cells. RESULTS Results from this cohort will enhance our understanding of the transmission of avian influenza viruses to humans in a country where such viruses are enzootic. CONCLUSIONS This may enhance public health efforts aimed at reducing this burden.
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Affiliation(s)
- Amira S El Rifay
- Center of Excellence for Influenza Viruses, National Research Centre, Giza, Egypt
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Qin Y, Horby PW, Tsang TK, Chen E, Gao L, Ou J, Nguyen TH, Duong TN, Gasimov V, Feng L, Wu P, Jiang H, Ren X, Peng Z, Li S, Li M, Zheng J, Liu S, Hu S, Hong R, Farrar JJ, Leung GM, Gao GF, Cowling BJ, Yu H. Differences in the Epidemiology of Human Cases of Avian Influenza A(H7N9) and A(H5N1) Viruses Infection. Clin Infect Dis 2015; 61:563-71. [PMID: 25940354 DOI: 10.1093/cid/civ345] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 04/21/2015] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND The pandemic potential of avian influenza viruses A(H5N1) and A(H7N9) remains an unresolved but critically important question. METHODS We compared the characteristics of sporadic and clustered cases of human H5N1 and H7N9 infection, estimated the relative risk of infection in blood-related contacts, and the reproduction number (R). RESULTS We assembled and analyzed data on 720 H5N1 cases and 460 H7N9 cases up to 2 November 2014. The severity and average age of sporadic/index cases of H7N9 was greater than secondary cases (71% requiring intensive care unit admission vs 33%, P = .007; median age 59 years vs 31, P < .001). We observed no significant differences in the age and severity between sporadic/index and secondary H5N1 cases. The upper limit of the 95% confidence interval (CI) for R was 0.12 for H5N1 and 0.27 for H7N9. A higher proportion of H5N1 infections occurred in clusters (20%) compared to H7N9 (8%). The relative risk of infection in blood-related contacts of cases compared to unrelated contacts was 8.96 for H5N1 (95% CI, 1.30, 61.86) and 0.80 for H7N9 (95% CI, .32, 1.97). CONCLUSIONS The results are consistent with an ascertainment bias towards severe and older cases for sporadic H7N9 but not for H5N1. The lack of evidence for ascertainment bias in sporadic H5N1 cases, the more pronounced clustering of cases, and the higher risk of infection in blood-related contacts, support the hypothesis that susceptibility to H5N1 may be limited and familial. This analysis suggests the potential pandemic risk may be greater for H7N9 than H5N1.
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Affiliation(s)
- Ying Qin
- Division of Infectious Disease, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Peter W Horby
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Vietnam Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, Oxford University, United Kingdom Singapore Infectious Disease Initiative
| | - Tim K Tsang
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region
| | - Enfu Chen
- Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou
| | - Lidong Gao
- Hunan Provincial Center for Disease Control and Prevention, Changsha
| | - Jianming Ou
- Fujian Provincial Center for Disease Control and Prevention, Fuzhou, China
| | | | - Tran Nhu Duong
- National Institute of Hygiene and Epidemiology, Hanoi, Vietnam
| | | | - Luzhao Feng
- Division of Infectious Disease, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Peng Wu
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region
| | - Hui Jiang
- Division of Infectious Disease, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Xiang Ren
- Division of Infectious Disease, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Zhibin Peng
- Division of Infectious Disease, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Sa Li
- Division of Infectious Disease, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Ming Li
- Division of Infectious Disease, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Jiandong Zheng
- Division of Infectious Disease, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Shelan Liu
- Zhejiang Provincial Center for Disease Control and Prevention, Hangzhou
| | - Shixiong Hu
- Hunan Provincial Center for Disease Control and Prevention, Changsha
| | - Rongtao Hong
- Fujian Provincial Center for Disease Control and Prevention, Fuzhou, China
| | - Jeremy J Farrar
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Vietnam Centre for Tropical Medicine, Nuffield Department of Clinical Medicine, Oxford University, United Kingdom Singapore Infectious Disease Initiative ISARIC, Centre for Tropical Medicine, University of Oxford, Churchill Hospital, United Kingdom
| | - Gabriel M Leung
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region
| | - George F Gao
- CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences Office of Director-General, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Benjamin J Cowling
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region
| | - Hongjie Yu
- Division of Infectious Disease, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, Beijing, China
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Studies on influenza virus transmission between ferrets: the public health risks revisited. mBio 2015; 6:mBio.02560-14. [PMID: 25616377 PMCID: PMC4323420 DOI: 10.1128/mbio.02560-14] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
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12
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Reply to "Studies on influenza virus transmission between ferrets: the public health risks revisited". mBio 2015; 6:mBio.00041-15. [PMID: 25616376 PMCID: PMC4323416 DOI: 10.1128/mbio.00041-15] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022] Open
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Gomaa MR, Kayed AS, Elabd MA, Zeid DA, Zaki SA, El Rifay AS, Sherif LS, McKenzie PP, Webster RG, Webby RJ, Ali MA, Kayali G. Avian influenza A(H5N1) and A(H9N2) seroprevalence and risk factors for infection among Egyptians: a prospective, controlled seroepidemiological study. J Infect Dis 2014; 211:1399-407. [PMID: 25355942 DOI: 10.1093/infdis/jiu529] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 08/05/2014] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND A(H5N1) and A(H9N2) avian influenza viruses are enzootic in Egyptian poultry, and most A(H5N1) human cases since 2009 have occurred in Egypt. Our understanding of the epidemiology of avian viruses in humans remains limited. Questions about the frequency of infection, the proportion of infections that are mild or subclinical, and the case-fatality rate remain largely unanswered. METHODS We conducted a 3-year, prospective, controlled, seroepidemiological study that enrolled 750 poultry-exposed and 250 unexposed individuals in Egypt. RESULTS At baseline, the seroprevalence of anti-A(H5N1) antibodies (titer, ≥80) among exposed individuals was 2% significantly higher than that among the controls (0%). Having chronic lung disease was a significant risk factor for infection. Antibodies against A(H9N2) were not detected at baseline when A(H9N2) was not circulating in poultry. At follow-up, A(H9N2) was detected in poultry, and consequently, the seroprevalence among exposed humans was between 5.6% and 7.5%. Vaccination of poultry, older age, and exposure to ducks were risk factors for A(H9N2) infection. CONCLUSIONS Results of this study indicate that the number of humans infected with avian influenza viruses is much larger than the number of reported confirmed cases. In an area where these viruses are enzootic in the poultry, human exposure to and infection with avian influenza becomes more common.
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Affiliation(s)
| | | | - Mona A Elabd
- Medical Research Division, National Research Center, Giza, Egypt
| | - Dina Abu Zeid
- Medical Research Division, National Research Center, Giza, Egypt
| | - Shaimaa A Zaki
- Medical Research Division, National Research Center, Giza, Egypt
| | - Amira S El Rifay
- Medical Research Division, National Research Center, Giza, Egypt
| | - Lobna S Sherif
- Medical Research Division, National Research Center, Giza, Egypt
| | - Pamela P McKenzie
- Division of Virology, Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee
| | - Robert G Webster
- Division of Virology, Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee
| | - Richard J Webby
- Division of Virology, Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee
| | | | - Ghazi Kayali
- Division of Virology, Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee
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Kobayashi-Ishihara M, Takahashi H, Ohnishi K, Nishimura K, Terahara K, Ato M, Itamura S, Kageyama T, Tsunetsugu-Yokota Y. Broad cross-reactive epitopes of the H5N1 influenza virus identified by murine antibodies against the A/Vietnam/1194/2004 hemagglutinin. PLoS One 2014; 9:e99201. [PMID: 24945805 PMCID: PMC4063728 DOI: 10.1371/journal.pone.0099201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Accepted: 05/12/2014] [Indexed: 01/07/2023] Open
Abstract
There is an urgent need for a rapid diagnostic system to detect the H5 subtype of the influenza A virus. We previously developed monoclonal antibodies (mAbs) against the H5 hemagglutinin (HA) for use in a rapid diagnostic kit. In this study, we determined the epitopes of the anti-H5 HA murine mAbs OM-b, AY-2C2, and YH-1A1. Binding assays of the mAbs to different strains of H5 HAs indicated that OM-b and AY-2C2 cross-reacted with HAs from clades 1, 2.1.3.2, 2.2, and 2.3.4, whereas YH-1A1 failed to bind to those of clades 2.1.3.2 and 2.3.4. HA chimeras revealed that the epitopes for each of the mAbs were in the HA1 region. Analysis of escape mutants revealed that OM-b and AY-2C2 mAbs interacted mainly with amino acid residues D43 and G46, and the YH-1A1 mAb interacted with G139 and K or R140 of H5 HA. Multiple alignments of H5 HA protein sequences showed that D43 and G46 were very conserved among H5N1 HAs, except those in clade 2.2.1 and clade 7 (88.7%). The epitope for YH-1A1 mAb was highly variable in the HAs of H5N1, although it was well conserved in those of H5N2-N9. The OM-b and AY-2C2 mAbs could bind to the HAs of clades 1.1 and 2.3.2.1 that are currently epidemic in Asia, and we conclude that these would be effective for the detection of H5N1 infections in this region.
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Affiliation(s)
- Mie Kobayashi-Ishihara
- Department of Immunology, National Institute of Infectious Diseases, Shinjuku, Tokyo, Japan
| | - Hitoshi Takahashi
- Influenza Virus Research Center, National Institute of Infectious Diseases, Musashimurayama, Tokyo, Japan
| | - Kazuo Ohnishi
- Department of Immunology, National Institute of Infectious Diseases, Shinjuku, Tokyo, Japan
| | - Kengo Nishimura
- Tsuruga Institute of Biotechnology, Toyobo, Co., Ltd., Tsuruga, Fukui, Japan
| | - Kazutaka Terahara
- Department of Immunology, National Institute of Infectious Diseases, Shinjuku, Tokyo, Japan
| | - Manabu Ato
- Department of Immunology, National Institute of Infectious Diseases, Shinjuku, Tokyo, Japan
| | - Shigeyuki Itamura
- Influenza Virus Research Center, National Institute of Infectious Diseases, Musashimurayama, Tokyo, Japan
| | - Tsutomu Kageyama
- Influenza Virus Research Center, National Institute of Infectious Diseases, Musashimurayama, Tokyo, Japan
| | - Yasuko Tsunetsugu-Yokota
- Department of Immunology, National Institute of Infectious Diseases, Shinjuku, Tokyo, Japan
- Department of Medical Technology, School of Human Sciences, Tokyo University of Technology, Ohta-ku, Tokyo, Japan
- * E-mail:
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Abstract
Influenza is an acute respiratory disease in mammals and domestic poultry that emerges from zoonotic reservoirs in aquatic birds and bats. Although influenza viruses are among the most intensively studied pathogens, existing control options require further improvement. Influenza vaccines must be regularly updated because of continuous antigenic drift and sporadic antigenic shifts in the viral surface glycoproteins. Currently, influenza therapeutics are limited to neuraminidase inhibitors; novel drugs and vaccine approaches are therefore urgently needed. Advances in vaccinology and structural analysis have revealed common antigenic epitopes on hemagglutinins across all influenza viruses and suggest that a universal influenza vaccine is possible. In addition, various immunomodulatory agents and signaling pathway inhibitors are undergoing preclinical development. Continuing challenges in influenza include the emergence of pandemic H1N1 influenza in 2009, human infections with avian H7N9 influenza in 2013, and sporadic human cases of highly pathogenic avian H5N1 influenza. Here, we review the challenges facing influenza scientists and veterinary and human public health officials; we also discuss the exciting possibility of achieving the ultimate goal of controlling influenza's ability to change its antigenicity.
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Affiliation(s)
- Robert G Webster
- Division of Virology, Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee
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Abstract
Please see later in the article for the Editors' Summary
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Affiliation(s)
- Marc Lipsitch
- Center for Communicable Disease Dynamics, Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts, United States of America
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, United States of America
- * E-mail:
| | - Alison P. Galvani
- Department of Epidemiology (Microbial Diseases), Yale School of Public Health, New Haven, Connecticut, United States of America
- Department of Ecology and Evolutionary Biology, Yale School of Public Health, New Haven, Connecticut, United States of America
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Van Kerkhove MD. Brief literature review for the WHO global influenza research agenda--highly pathogenic avian influenza H5N1 risk in humans. Influenza Other Respir Viruses 2014; 7 Suppl 2:26-33. [PMID: 24034480 DOI: 10.1111/irv.12077] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Highly pathogenic avian influenza A H5N1 viruses remain a significant health threat to humans given the continued rare occurrence of human cases with a high case fatality rate. This brief literature review summarizes available evidence of risk factors for H5N1 infection in humans and updates a recent systematic review published in early 2011. Several epidemiologic studies have been published to evaluate the risk factors for H5N1 infection in humans, including contact with poultry and poultry products and non-poultry-related contact such as from H5N1-contaminated water. While most H5N1 cases are attributed to exposure to sick poultry, it is unclear how many may be due to human-to-human transmission. The collective results of published literature suggest that transmission risk of H5N1 from poultry to humans may be highest among individuals who may have been in contact with the highest potential concentrations of virus shed by poultry. This suggests that there may be a threshold of virus concentration needed for effective transmission and that circulating H5N1 strains have not yet mutated to transmit readily from either poultry to human or from human to human. However, the mode of potential transmission can be quite varied throughout different countries and by study with exposures ranging from visiting a wet market, preparing infected poultry for consumption, to swimming or bathing in ponds frequented by poultry. Several important data gaps remain in the understanding of the epidemiology of H5N1 in humans and limit our ability to interpret the results of the available H5N1 seroepidemiologic studies.
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Affiliation(s)
- Maria D Van Kerkhove
- MRC Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College London, London, UK
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Le MQ, Horby P, Fox A, Nguyen HT, Le Nguyen HK, Hoang PMV, Nguyen KC, de Jong MD, Jeeninga RE, Rogier van Doorn H, Farrar J, Wertheim HFL. Subclinical avian influenza A(H5N1) virus infection in human, Vietnam. Emerg Infect Dis 2014; 19:1674-7. [PMID: 24047510 PMCID: PMC3810763 DOI: 10.3201/eid1910.130730] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Laboratory-confirmed cases of subclinical infection with avian influenza A(H5N1) virus in humans are rare, and the true number of these cases is unknown. We describe the identification of a laboratory-confirmed subclinical case in a woman during an influenza A(H5N1) contact investigation in northern Vietnam.
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Patel RB, Mathur MB, Gould M, Uyeki TM, Bhattacharya J, Xiao Y, Khazeni N. Demographic and clinical predictors of mortality from highly pathogenic avian influenza A (H5N1) virus infection: CART analysis of international cases. PLoS One 2014; 9:e91630. [PMID: 24667532 PMCID: PMC3965392 DOI: 10.1371/journal.pone.0091630] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2013] [Accepted: 02/11/2014] [Indexed: 11/19/2022] Open
Abstract
Background Human infections with highly pathogenic avian influenza (HPAI) A (H5N1) viruses have occurred in 15 countries, with high mortality to date. Determining risk factors for morbidity and mortality from HPAI H5N1 can inform preventive and therapeutic interventions. Methods We included all cases of human HPAI H5N1 reported in World Health Organization Global Alert and Response updates and those identified through a systematic search of multiple databases (PubMed, Scopus, and Google Scholar), including articles in all languages. We abstracted predefined clinical and demographic predictors and mortality and used bivariate logistic regression analyses to examine the relationship of each candidate predictor with mortality. We developed and pruned a decision tree using nonparametric Classification and Regression Tree methods to create risk strata for mortality. Findings We identified 617 human cases of HPAI H5N1 occurring between December 1997 and April 2013. The median age of subjects was 18 years (interquartile range 6–29 years) and 54% were female. HPAI H5N1 case-fatality proportion was 59%. The final decision tree for mortality included age, country, per capita government health expenditure, and delay from symptom onset to hospitalization, with an area under the receiver operator characteristic (ROC) curve of 0.81 (95% CI: 0.76–0.86). Interpretation A model defined by four clinical and demographic predictors successfully estimated the probability of mortality from HPAI H5N1 illness. These parameters highlight the importance of early diagnosis and treatment and may enable early, targeted pharmaceutical therapy and supportive care for symptomatic patients with HPAI H5N1 virus infection.
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Affiliation(s)
- Rita B. Patel
- Division of Pulmonary and Critical Care Medicine, Stanford University Medical Center, Stanford, California, United States of America
| | - Maya B. Mathur
- Division of Pulmonary and Critical Care Medicine, Stanford University Medical Center, Stanford, California, United States of America
- * E-mail:
| | - Michael Gould
- Kaiser Permanente Southern California, Pasadena, California, United States of America
| | - Timothy M. Uyeki
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
| | - Jay Bhattacharya
- Center for Health Policy and Center for Primary Care and Outcomes Research, Stanford University, Stanford, California, United States of America
| | - Yang Xiao
- Department of Languages, Literatures, and Cultures, University of South Carolina, Columbia, South Carolina, United States of America
| | - Nayer Khazeni
- Division of Pulmonary and Critical Care Medicine, Stanford University Medical Center, Stanford, California, United States of America
- Center for Health Policy and Center for Primary Care and Outcomes Research, Stanford University, Stanford, California, United States of America
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Mertz D, Kim TH, Johnstone J, Lam PP, Science M, Kuster SP, Fadel SA, Tran D, Fernandez E, Bhatnagar N, Loeb M. Populations at risk for severe or complicated Avian Influenza H5N1: a systematic review and meta-analysis. PLoS One 2014; 9:e89697. [PMID: 24603885 PMCID: PMC3948335 DOI: 10.1371/journal.pone.0089697] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 01/21/2014] [Indexed: 11/24/2022] Open
Abstract
Background Little is known about risk factors for severe outcomes in patients infected with H5N1 and no systematic review has been conducted. Understanding risk factors is an important step for prioritizing prophylaxis or treatment in the event of a pandemic. Objectives To systematically evaluate risk factors for severe outcomes in patients with avian influenza H5N1 infection. Data sources MEDLINE, EMBASE, CINAHL, GlobalHealth, and CENTRAL through March 2011 Eligibility criteria for selecting studies Observational studies of any design published in English, French, Spanish, German or Korean that reported on risk factor-outcome combinations of interest in participants with confirmed H5N1 infections. Outcomes considered included death, ventilator support, hospital and ICU admission, pneumonia, and composite outcomes. Study appraisal Risk of bias was assessed using the Newcastle-Ottawa scale (NOS). Results We identified 20 studies reporting on 999 patients infected with H5N1. The majority of studies (n = 14, 70%) were at intermediate risk of bias, i.e. 4–6 points on the NOS. Females were at increased risk of death (OR 1.75, 95% CI 1.27–2.44), while young age, in particular <5 years of age (OR 0.44, 95% CI 0.25–0.79 for death), was protective. Data on traditional risk factors was scarce and requires further studies. Another major limitation in the published literature was lack of adjustment for confounders. Interpretation Females were at increased risk for complications following H5N1 infection while young age protected against severe outcomes. Research on traditional risk factors was limited and is required.
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Affiliation(s)
- Dominik Mertz
- Department of Medicine, McMaster University, Hamilton, Ontario, Canada
- Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario, Canada
- Michael G. DeGroote Institute for Infectious Diseases Research, McMaster University, Hamilton, Ontario, Canada
| | - Tae Hyong Kim
- Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario, Canada
- Division of Infectious Diseases, Departments of Internal Medicine, Soon Chun Hyang University Seoul Hospital, Seoul, Republic of Korea
| | - Jennie Johnstone
- Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario, Canada
| | - Po-Po Lam
- Department of Microbiology, Mount Sinai Hospital, Toronto, Ontario, Canada
- Division of Epidemiology, Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
| | - Michelle Science
- Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario, Canada
- Division of Infectious Diseases, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Ontario, Canada
| | - Stefan P. Kuster
- Department of Microbiology, Mount Sinai Hospital, Toronto, Ontario, Canada
- Division of Infectious Diseases and Hospital Epidemiology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Shaza A. Fadel
- Division of Epidemiology, Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada
| | - Dat Tran
- Division of Infectious Diseases, Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Ontario, Canada
| | - Eduardo Fernandez
- Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario, Canada
| | - Neera Bhatnagar
- Health Sciences Library, McMaster University, Hamilton, Ontario, Canada
| | - Mark Loeb
- Department of Medicine, McMaster University, Hamilton, Ontario, Canada
- Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario, Canada
- Michael G. DeGroote Institute for Infectious Diseases Research, McMaster University, Hamilton, Ontario, Canada
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
- * E-mail:
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Yu H, Cowling BJ, Feng L, Lau EHY, Liao Q, Tsang TK, Peng Z, Wu P, Liu F, Fang VJ, Zhang H, Li M, Zeng L, Xu Z, Li Z, Luo H, Li Q, Feng Z, Cao B, Yang W, Wu JT, Wang Y, Leung GM. Human infection with avian influenza A H7N9 virus: an assessment of clinical severity. Lancet 2013; 382:138-45. [PMID: 23803487 PMCID: PMC3801178 DOI: 10.1016/s0140-6736(13)61207-6] [Citation(s) in RCA: 209] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
BACKGROUND Characterisation of the severity profile of human infections with influenza viruses of animal origin is a part of pandemic risk assessment, and an important part of the assessment of disease epidemiology. Our objective was to assess the clinical severity of human infections with avian influenza A H7N9 virus, which emerged in China in early 2013. METHODS We obtained information about laboratory-confirmed cases of avian influenza A H7N9 virus infection reported as of May 28, 2013, from an integrated database built by the Chinese Center for Disease Control and Prevention. We estimated the risk of fatality, mechanical ventilation, and admission to the intensive care unit for patients who required hospital admission for medical reasons. We also used information about laboratory-confirmed cases detected through sentinel influenza-like illness surveillance to estimate the symptomatic case fatality risk. FINDINGS Of 123 patients with laboratory-confirmed avian influenza A H7N9 virus infection who were admitted to hospital, 37 (30%) had died and 69 (56%) had recovered by May 28, 2013. After we accounted for incomplete data for 17 patients who were still in hospital, we estimated the fatality risk for all ages to be 36% (95% CI 26-45) on admission to hospital. Risks of mechanical ventilation or fatality (69%, 95% CI 60-77) and of admission to an intensive care unit, mechanical ventilation, or fatality (83%, 76-90) were high. With assumptions about coverage of the sentinel surveillance network and health-care-seeking behaviour for patients with influenza-like illness associated with influenza A H7N9 virus infection, and pro-rata extrapolation, we estimated that the symptomatic case fatality risk could be between 160 (63-460) and 2800 (1000-9400) per 100,000 symptomatic cases. INTERPRETATION Human infections with avian influenza A H7N9 virus seem to be less serious than has been previously reported. Many mild cases might already have occurred. Continued vigilance and sustained intensive control efforts are needed to minimise the risk of human infection. FUNDING Chinese Ministry of Science and Technology; Research Fund for the Control of Infectious Disease; Hong Kong University Grants Committee; China-US Collaborative Program on Emerging and Re-emerging Infectious Diseases; Harvard Center for Communicable Disease Dynamics; US National Institute of Allergy and Infectious Disease; and the US National Institutes of Health.
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Affiliation(s)
- Hongjie Yu
- Division of Infectious Disease, Key Laboratory of Surveillance and Early-warning on Infectious Disease, Chinese Center for Disease Control and Prevention, Beijing, China
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Toner ES, Adalja AA, Nuzzo JB, Inglesby TV, Henderson DA, Burke DS. Assessment of serosurveys for H5N1. Clin Infect Dis 2013; 56:1206-12. [PMID: 23386633 DOI: 10.1093/cid/cit047] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND It has been suggested that the true case-fatality rate of human H5N1 influenza infection is appreciably less than the figure of approximately 60% that is based on official World Health Organization (WHO)-confirmed case reports because asymptomatic cases may have been missed. A number of seroepidemiologic studies have been conducted in an attempt to identify such missed cases. METHODS We conducted a comprehensive literature review of all English-language H5N1 human serology surveys with detailed attention to laboratory methodology used (including whether investigators used criteria set by the WHO to define positive cases), laboratory controls used, and the clades/genotypes involved. RESULTS Twenty-nine studies were included in the analysis. Few reported using unexposed control groups and one-third did not apply WHO criteria. Of studies that used WHO criteria, only 4 found any seropositive results to clades/genotypes of H5N1 that are currently circulating. No studies reported seropositive results to the clade 2/genotype Z viruses that have spread throughout Eurasia and Africa. CONCLUSIONS This review suggests that the frequency of positive H5 serology results is likely to be low; therefore, it is essential that future studies adhere to WHO criteria and include unexposed controls in their laboratory assays to limit the likelihood of false-positive results.
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Affiliation(s)
- Eric S Toner
- Center for Biosecurity, University of Pittsburgh Medical Center, Baltimore, MD 21202, USA.
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Boni MF, Nguyen TD, de Jong MD, van Doorn HR. Virulence attenuation during an influenza A/H5N1 pandemic. Philos Trans R Soc Lond B Biol Sci 2013; 368:20120207. [PMID: 23382429 PMCID: PMC3675429 DOI: 10.1098/rstb.2012.0207] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
More than 15 years after the first human cases of influenza A/H5N1 in Hong Kong, the world remains at risk for an H5N1 pandemic. Preparedness activities have focused on antiviral stockpiling and distribution, development of a human H5N1 vaccine, operationalizing screening and social distancing policies, and other non-pharmaceutical interventions. The planning of these interventions has been done in an attempt to lessen the cumulative mortality resulting from a hypothetical H5N1 pandemic. In this theoretical study, we consider the natural limitations on an H5N1 pandemic's mortality imposed by the virus' epidemiological–evolutionary constraints. Evolutionary theory dictates that pathogens should evolve to be relatively benign, depending on the magnitude of the correlation between a pathogen's virulence and its transmissibility. Because the case fatality of H5N1 infections in humans is currently 60 per cent, it is doubtful that the current viruses are close to their evolutionary optimum for transmission among humans. To describe the dynamics of virulence evolution during an H5N1 pandemic, we build a mathematical model based on the patterns of clinical progression in past H5N1 cases. Using both a deterministic model and a stochastic individual-based simulation, we describe (i) the drivers of evolutionary dynamics during an H5N1 pandemic, (ii) the range of case fatalities for which H5N1 viruses can successfully cause outbreaks in humans, and (iii) the effects of different kinds of social distancing on virulence evolution. We discuss two main epidemiological–evolutionary features of this system (i) the delaying or slowing of an epidemic which results in a majority of hosts experiencing an attenuated virulence phenotype and (ii) the strong evolutionary pressure for lower virulence experienced by the virus during a period of intense social distancing.
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Affiliation(s)
- Maciej F Boni
- Oxford University Clinical Research Unit, Wellcome Trust Major Overseas Programme, Ho Chi Minh City, Vietnam.
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25
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Abstract
If accidentally released, mammalian-transmissible influenza A/H5N1 viruses could pose a greater threat to public health than possibly any other infectious agent currently under study in laboratories, because of such viruses’ likely combination of transmissibility and virulence to humans. We advocate explicit risk-benefit assessments before work on such pathogens is permitted or funded, improvement of biosafety practices and enforcement, and harmonization of criteria for permitting such experiments across government agencies, as well as internationally. Such potential pandemic pathogens, as they have been called, jeopardize not only laboratory workers and their contacts, but also the wider population, who should be involved in assessments of when such risks are acceptable in the service of scientific knowledge that may itself bear major public health benefits.
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Wang TT, Palese P. Response to Comment on “Seroevidence for H5N1 Influenza Infections in Humans: Meta-Analysis”. Science 2012. [DOI: 10.1126/science.1221633] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
We address points made in the comment by Van Kerkhove
et al
. and explain why human H5N1 virus infections are much more common than was previously thought.
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Affiliation(s)
- Taia T. Wang
- Department of Microbiology, Mount Sinai School of Medicine, New York, NY 10029, USA
| | - Peter Palese
- Department of Microbiology, Mount Sinai School of Medicine, New York, NY 10029, USA
- Department of Medicine, Mount Sinai School of Medicine, New York, NY 10029, USA
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