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Mellou K, Tryfinopoulou K, Emmanouil M, Gkolfinopoulou K, Sapounas S, Evangelidou M, Moulopoulou P, Miaoulis E, Angelakis E, Sourvinos G, Zaoutis T, Paraskevis D. Influenza transmission during COVID-19 measures downscaling in Greece, August 2022: evidence for the need of continuous integrated surveillance of respiratory viruses. Euro Surveill 2023; 28:2200754. [PMID: 37440348 PMCID: PMC10347892 DOI: 10.2807/1560-7917.es.2023.28.28.2200754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Accepted: 04/05/2023] [Indexed: 07/15/2023] Open
Abstract
After the near absence of influenza and other respiratory viruses during the first 2 years of the COVID-19 pandemic, an increased activity of mainly influenza A(H3N2) was detected at the beginning of August 2022 in Greece on three islands. Of 33 cases with respiratory symptoms testing negative for SARS-CoV-2 with rapid antigen tests, 24 were positive for influenza: 20 as A(H3N2) subtype and four as A(H1N1)pdm09 subtype. Phylogenetic analysis of selected samples from both subtypes was performed and they fell into clusters within subclades that included the 2022/23 vaccine strains. Our data suggest that influenza can be transmitted even in the presence of another highly infectious pathogen, such as SARS-CoV-2, with a similar transmission mode. We highlight the need for implementing changes in the current influenza surveillance and suggest a move from seasonal to continuous surveillance, especially in areas with a high number of tourists. Year-round surveillance would allow for a timelier start of vaccination campaigns and antiviral drugs procurement processes.
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Affiliation(s)
| | | | - Mary Emmanouil
- Diagnostic Department and Public Health Laboratories, Hellenic Pasteur Institute, Athens, Greece
| | | | | | - Maria Evangelidou
- Diagnostic Department and Public Health Laboratories, Hellenic Pasteur Institute, Athens, Greece
| | | | | | - Emmanouil Angelakis
- Diagnostic Department and Public Health Laboratories, Hellenic Pasteur Institute, Athens, Greece
| | - George Sourvinos
- Laboratory of Clinical Virology, School of Medicine, University of Crete, Heraklion, Greece
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2
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Maltezou HC, Asimakopoulos G, Stavrou S, Daskalakis G, Koutroumanis P, Sindos M, Theodora M, Katerelos P, Kostis E, Gavrili S, Kossyvakis A, Theodoridou M, Mentis A, Drakakis P, Loutradis D, Rodolakis A. Effectiveness of quadrivalent influenza vaccine in pregnant women and infants, 2018-2019. Vaccine 2020; 38:4625-4631. [PMID: 32402751 DOI: 10.1016/j.vaccine.2020.04.060] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Revised: 04/21/2020] [Accepted: 04/23/2020] [Indexed: 01/01/2023]
Abstract
Influenza is associated with an increased risk for serious illness, hospitalization and/or death in pregnant women and young infants. We prospectively studied the effectiveness of a quadrivalent inactivated influenza vaccine (QIV) in pregnant women and their infants during the 2018-2019 influenza season. A QIV was offered to pregnant women cared in a maternity hospital in Athens. Women were contacted weekly by telephone during the influenza season and PCR test was offered to women or infants who developed influenza-like illness (ILI). We studied 423 pregnant women and 446 infants. Unvaccinated pregnant women had a 7.5% probability to develop laboratory-confirmed influenza compared to 2.1% among vaccinated women (Odds ratio: 3.6; confidence intervals: 1.14-11.34, p-value = 0.029). Infants whose mothers were not vaccinated had a 7.9% probability to develop laboratory-confirmed influenza compared to 2.8% among infants of vaccinated mothers (Odds ratio = 2.849, confidence intervals: 0.892-9.102, p-value = 0.053). Cox regression analyses showed that QIV vaccination was significantly associated with a decreased probability for laboratory-confirmed influenza, ILI, healthcare seeking and hospitalization among pregnant women and a decreased probability for laboratory-confirmed influenza, healthcare seeking and prescription of antibiotics among infants. The effectiveness of QIV against laboratory-confirmed influenza was 72% among pregnant women and 64.5% among infants during the 2018-2019 influenza season. Vaccination of pregnant women with the QIV was associated with a lower risk for laboratory-confirmed influenza for them and their infants during the influenza season. Our findings strongly support the World Health Organization recommendations for vaccinating pregnant women against influenza.
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Affiliation(s)
- Helena C Maltezou
- Directorate of Epidemiological Surveillance and Interventions for Infectious Diseases, National Public Health Organization, Athens, Greece.
| | - George Asimakopoulos
- First Department of Gynecology and Obstetrics, National Kapodistrian University of Athens, Alexandra General Hospital, Athens, Greece
| | - Sofoklis Stavrou
- First Department of Gynecology and Obstetrics, National Kapodistrian University of Athens, Alexandra General Hospital, Athens, Greece
| | - George Daskalakis
- First Department of Gynecology and Obstetrics, National Kapodistrian University of Athens, Alexandra General Hospital, Athens, Greece
| | - Pelopidas Koutroumanis
- First Department of Gynecology and Obstetrics, National Kapodistrian University of Athens, Alexandra General Hospital, Athens, Greece
| | - Michael Sindos
- First Department of Gynecology and Obstetrics, National Kapodistrian University of Athens, Alexandra General Hospital, Athens, Greece
| | - Marianna Theodora
- First Department of Gynecology and Obstetrics, National Kapodistrian University of Athens, Alexandra General Hospital, Athens, Greece
| | - Panos Katerelos
- Directorate of Epidemiological Surveillance and Interventions for Infectious Diseases, National Public Health Organization, Athens, Greece
| | | | - Stavroula Gavrili
- Neonatal Intensive Care Unit, Alexandra General Hospital, Athens, Greece
| | - Athanassios Kossyvakis
- National Influenza Reference Laboratory of Southern Greece, Hellenic Pasteur Institute, Athens, Greece
| | - Maria Theodoridou
- First Department of Pediatrics, National Kapodistrian University of Athens, Aghia Sophia Children's Hospital, Athens, Greece
| | - Andreas Mentis
- National Influenza Reference Laboratory of Southern Greece, Hellenic Pasteur Institute, Athens, Greece
| | - Petros Drakakis
- First Department of Gynecology and Obstetrics, National Kapodistrian University of Athens, Alexandra General Hospital, Athens, Greece
| | - Dimitrios Loutradis
- First Department of Gynecology and Obstetrics, National Kapodistrian University of Athens, Alexandra General Hospital, Athens, Greece
| | - Alexandros Rodolakis
- First Department of Gynecology and Obstetrics, National Kapodistrian University of Athens, Alexandra General Hospital, Athens, Greece
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3
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Mouratidou E, Lambrou A, Andreopoulou A, Gioula G, Exindari M, Kossyvakis A, Pogka V, Mentis A, Georgakopoulou T, Lytras T. Influenza vaccine effectiveness against hospitalization with laboratory-confirmed influenza in Greece: A pooled analysis across six seasons, 2013-2014 to 2018-2019. Vaccine 2020; 38:2715-2724. [PMID: 32033848 DOI: 10.1016/j.vaccine.2020.01.083] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 01/24/2020] [Accepted: 01/27/2020] [Indexed: 11/24/2022]
Abstract
BACKGROUND Monitoring seasonal influenza Vaccine Effectiveness (VE) is key to inform vaccination strategies and sustain uptake. Pooling data across multiple seasons increases precision and allows for subgroup analyses, providing more conclusive evidence. Our aim was to assess VE against hospitalization with laboratory-confirmed influenza in Greece over six seasons, from 2013 to 2014 to 2018-2019, using routinely collected surveillance data. METHODS Swab samples from hospitalized patients across the country were tested for influenza by RT-PCR. We used the test-negative design, with patients testing positive for influenza serving as cases and those testing negative serving as controls. VE was calculated as one minus the Odds Ratio (OR) for influenza vaccination, estimated by mixed-effects logistic regression and adjusted for age, sex, hospitalization type (being in intensive care or not), time from symptom onset to swabbing, and calendar time. Stratified estimates by age and hospitalization type were obtained, and also subgroup estimates by influenza type/subtype and season. Antigenic and genetic characterization of a subset of circulating influenza strains was performed. RESULTS A total of 3,882 test-positive cases and 5,895 test-negative controls were analyzed. Across all seasons, adjusted VE was 45.5% (95% CI: 31.6-56.6) against all influenza, 62.8% against A(H1N1)pdm09 (95% CI: 40.7-76.7), 28.2% against A(H3N2) (95% CI: 12.0-41.3) and 45.5% against influenza B (95% CI: 29.1-58.1). VE was slightly lower for patients aged 60 years and over, and similar between patients hospitalized inside or outside intensive care. Circulating A(H1N1)pdm09 and B strains were antigenically similar to the vaccine strains, whereas A(H3N2) were not. CONCLUSION Our results confirm the public health benefits from seasonal influenza vaccination, despite the suboptimal effectiveness against A(H3N2) strains. Continued monitoring of VE is essential, and routinely collected surveillance data can be valuable in this regard.
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Affiliation(s)
- Elisavet Mouratidou
- National Public Health Organization, Athens, Greece; European Programme for Intervention Epidemiology Training (EPIET), European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden.
| | | | | | - Georgia Gioula
- National Influenza Centre for Northern Greece, Medical School, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Maria Exindari
- National Influenza Centre for Northern Greece, Medical School, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Athanasios Kossyvakis
- National Influenza Centre for Southern Greece, Hellenic Pasteur Institute, Athens, Greece
| | - Vasiliki Pogka
- National Influenza Centre for Southern Greece, Hellenic Pasteur Institute, Athens, Greece
| | - Andreas Mentis
- National Influenza Centre for Southern Greece, Hellenic Pasteur Institute, Athens, Greece
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4
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Rath B, Maltezou HC, Papaevangelou V, Papagrigoriou-Theodoridou MA, Alchikh M, Myles P, Schweiger B. Partnering for enhanced digital surveillance of influenza-like disease and the effect of antivirals and vaccines (PEDSIDEA). Influenza Other Respir Viruses 2019; 13:309-318. [PMID: 31169347 PMCID: PMC6586183 DOI: 10.1111/irv.12645] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Accepted: 03/15/2019] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Standardised clinical outcome measures are urgently needed for the surveillance of influenza and influenza-like illness (ILI) based on individual patient data (IPD). OBJECTIVES We report a multicentre prospective cohort using a predefined disease severity score in routine care. PATIENTS/METHODS The Vienna Vaccine Safety initiative (ViVI) Disease Severity Score ("ViVI Score") was made available as an android-based mobile application to three paediatric hospitals in Berlin and Athens between 2013 and 2016. Healthcare professionals assessed ILI patients at the point of care including severity, risk factors and use of antibiotics/antivirals/vaccines. RT-PCR for influenza A/B viruses was performed at the Hellenic Pasteur Institute and the Robert Koch Institute. PCR testing was blinded to severity scoring and vice versa. RESULTS A total of 1615 children aged 0-5 years (54.4% males) were assessed at the three sites. The mean age was 1.7 years (SD 1.5; range 0-5.9). The success rate (completion of the scoring without disruption to the ER workflow) was 100%. ViVI Disease Severity Scores ranged from 0 to 35 (mean 13.72). Disease severity in the Berlin Cohort was slightly higher (mean 15.26) compared to the Athens Cohorts (mean 10.86 and 11.13). The administration of antibiotics was most prevalent in the Berlin Cohort, with 41.2% on antibiotics (predominantly cefuroxime) as opposed to only 0.5% on neuraminidase inhibitors. Overall, Risk-adjusted ViVI Scores were significantly linked to the prescription of both, antibiotics and antivirals. CONCLUSIONS The Risk-adjusted ViVI Score enables a precision medicine approach to managing ILI in multicentre settings. Using mobile applications, severity data will be obtained in real time with important implications for the evaluation of antiviral/vaccine use.
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Affiliation(s)
- Barbara Rath
- Vienna Vaccine Safety Initiative, Berlin, Germany.,Department of Epidemiology and Public Health, The University of Nottingham School of Medicine, Nottingham, UK
| | - Helena C Maltezou
- Department for Interventions in Healthcare Facilities, Hellenic Centre for Disease Control and Prevention, Athens, Greece
| | - Vassiliki Papaevangelou
- Third Department of Paediatrics, University General Hospital 'Attikon', National Kapodistrian University of Athens, Athens, Greece
| | | | - Maren Alchikh
- Vienna Vaccine Safety Initiative, Berlin, Germany.,Department of Paediatrics, Charité University Medical Centre, Berlin, Germany
| | - Puja Myles
- Department of Epidemiology and Public Health, The University of Nottingham School of Medicine, Nottingham, UK
| | - Brunhilde Schweiger
- National Reference Centre for Influenza, Robert Koch Institute, Berlin, Germany
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5
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Melidou A, Gioula G, Exindari M, Ioannou E, Gkolfinopoulou K, Georgakopoulou T, Tsiodras S, Papa A. Ιnfluenza A(H3N2) genetic variants in vaccinated patients in northern Greece. J Clin Virol 2017; 94:29-32. [PMID: 28734139 DOI: 10.1016/j.jcv.2017.07.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2017] [Revised: 06/29/2017] [Accepted: 07/08/2017] [Indexed: 10/19/2022]
Abstract
BACKGROUND Influenza A(H3N2) viruses predominated during the influenza 2016/2017 season and showed extensive genetic diversification. A high vaccination failure rate was noticed during the 2016/17 season in Greece, especially among the elderly. OBJECTIVES The scope of the study was to investigate the genetic characteristics of A(H3N2) circulating viruses and viruses detected in vaccinated patients. STUDY DESIGN Virus samples originated from vaccinated and unvaccinated patients, obtained at the National Influenza Centre for northern Greece. Phylogenetic analysis and comparison of the haemagglutinin gene of the viruses to the vaccine virus A/Hong Kong/4801/2014 was performed. RESULTS The majority of analysed viruses are clustering in the genetic clade 3C.2a, and in a newly emerged subclade, designated as 3C.2a1. The highest proportion of viruses detected in vaccinated patients fell into a distinct subcluster within the 3C.2a1 subclade, which is characterised by the amino acid substitutions N122D and T135K in haemagglutinin. CONCLUSIONS Viruses that belong to the 3C.2a clade are generally considered to resemble antigenically to the northern hemisphere vaccine component A/Hong Kong/4801/2014 that was recommended by WHO to be included also into the 2017/18 vaccine. However, viruses belonging to a specific 3C.2a1 subcluster was extensively circulating in northern Greece and among vaccinated individuals. Both substitutions carried by this strain were located on antigenic sites and caused losses of N-linked glycosylation sites of the virus, which could potentially affect viral antigenicity. Further studies are needed to determine the antigenicity of this variant strain and its possible implication in vaccine effectiveness.
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Affiliation(s)
- A Melidou
- National Influenza Centre for northern Greece, Department of Microbiology, Medical School, Aristotle University of Thessaloniki, Greece.
| | - G Gioula
- National Influenza Centre for northern Greece, Department of Microbiology, Medical School, Aristotle University of Thessaloniki, Greece
| | - M Exindari
- National Influenza Centre for northern Greece, Department of Microbiology, Medical School, Aristotle University of Thessaloniki, Greece
| | - E Ioannou
- National Influenza Centre for northern Greece, Department of Microbiology, Medical School, Aristotle University of Thessaloniki, Greece
| | - K Gkolfinopoulou
- Hellenic Centre for Disease Control and Prevention (KEELPNO), Athens, Greece
| | - T Georgakopoulou
- Hellenic Centre for Disease Control and Prevention (KEELPNO), Athens, Greece
| | - S Tsiodras
- Hellenic Centre for Disease Control and Prevention (KEELPNO), Athens, Greece; 4th Department of Internal Medicine, National and Kapodistrian University of Athens Medical School, Athens, Greece
| | - A Papa
- National Influenza Centre for northern Greece, Department of Microbiology, Medical School, Aristotle University of Thessaloniki, Greece
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6
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Kossyvakis A, Mentis AFA, Tryfinopoulou K, Pogka V, Kalliaropoulos A, Antalis E, Lytras T, Meijer A, Tsiodras S, Karakitsos P, Mentis AF. Antiviral susceptibility profile of influenza A viruses; keep an eye on immunocompromised patients under prolonged treatment. Eur J Clin Microbiol Infect Dis 2016; 36:361-371. [PMID: 27848039 DOI: 10.1007/s10096-016-2809-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 10/03/2016] [Indexed: 11/24/2022]
Abstract
There was an increase in severe and fatal influenza cases in Greece during the 2011-2015 post-pandemic period. To investigate causality, we determined neuraminidase (NA) inhibitor susceptibility and resistance-conferring NA and hemagglutinin (HA) mutations in circulating influenza type A viruses during the pandemic (2009-2010) and post-pandemic periods in Greece. One hundred thirty-four influenza A(H1N1)pdm09 and 95 influenza A(H3N2) viruses submitted to the National Influenza Reference Laboratory of Southern Greece were tested for susceptibility to oseltamivir and zanamivir. Antiviral resistance was assessed by neuraminidase sequence analysis, as well as the fluorescence-based 50 % inhibitory concentration (IC50) method. Five influenza A(H1N1)pdm09 viruses (2.2 %) showed significantly reduced inhibition by oseltamivir (average IC50 300.60nM vs. 1.19nM) by Gaussian kernel density plot analysis. These viruses were isolated from immunocompromised patients and harbored the H275Y oseltamivir resistance-conferring NA substitution. All A(H1N1)pdm09 viruses were zanamivir-susceptible, and all A(H3N2) viruses were susceptible to both drugs. Oseltamivir-resistant viruses did not form a distinct cluster by phylogenetic analysis. Permissive mutations were detected in immunogenic and non immunogenic NA regions of both oseltamivir- resistant and susceptible viruses in the post-pandemic seasons. Several amino acid substitutions in the HA1 domain of the HA gene of post-pandemic viruses were identified. This study indicated low resistance to NAIs among tested influenza viruses. Antiviral resistance emerged only in immunocompromised patients under long-term oseltamivir treatment. Sequential sample testing in this vulnerable group of patients is recommended to characterise resistance or reinfection and viral evolution.
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Affiliation(s)
- A Kossyvakis
- National Influenza Reference Laboratory of Southern Greece, Hellenic Pasteur Institute, 127, Vas. Sofias Ave., 11521, Athens, Greece
| | - A-F A Mentis
- National Influenza Reference Laboratory of Southern Greece, Hellenic Pasteur Institute, 127, Vas. Sofias Ave., 11521, Athens, Greece.,Johns Hopkins University, AAP, Baltimore, MD, USA
| | - K Tryfinopoulou
- European Programme for Public Health Microbiology Training (EUPHEM), European Centre for Disease Prevention and Control, Stockholm, Sweden.,Antimicrobial Resistance and Healthcare-associated Infections Laboratory, National School of Public Health, Athens, Greece.,Hellenic Central Public Health Laboratory, Hellenic Centre for Disease Control and Prevention, Athens, Greece
| | - V Pogka
- National Influenza Reference Laboratory of Southern Greece, Hellenic Pasteur Institute, 127, Vas. Sofias Ave., 11521, Athens, Greece
| | - A Kalliaropoulos
- National Influenza Reference Laboratory of Southern Greece, Hellenic Pasteur Institute, 127, Vas. Sofias Ave., 11521, Athens, Greece
| | - E Antalis
- 4th Academic Department of Internal Medicine and Infectious Diseases, Attikon University Hospital, University of Athens Medical School, Athens, Greece
| | - T Lytras
- Department of Epidemiological Surveillance and Intervention, Hellenic Centre for Disease Control and Prevention, Athens, Greece.,Centre for Research in Environmental Epidemiology (CREAL), Barcelona, Spain.,Department of Experimental and Health Sciences, Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - A Meijer
- National Institute for Public Health and the Environment, Centre for Infectious Disease Control, Bilthoven, Netherlands
| | - S Tsiodras
- 4th Academic Department of Internal Medicine and Infectious Diseases, Attikon University Hospital, University of Athens Medical School, Athens, Greece
| | - P Karakitsos
- Department of Cytopathology, Attikon University Hospital, University of Athens Medical School, Athens, Greece
| | - A F Mentis
- National Influenza Reference Laboratory of Southern Greece, Hellenic Pasteur Institute, 127, Vas. Sofias Ave., 11521, Athens, Greece.
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7
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Broberg E, Hungnes O, Schweiger B, Prosenc K, Daniels R, Guiomar R, Ikonen N, Kossyvakis A, Pozo F, Puzelli S, Thomas I, Waters A, Wiman Å, Meijer A. Improving influenza virological surveillance in Europe: strain-based reporting of antigenic and genetic characterisation data, 11 European countries, influenza season 2013/14. Euro Surveill 2016; 21:30370. [PMID: 27762211 PMCID: PMC5073191 DOI: 10.2807/1560-7917.es.2016.21.41.30370] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 04/25/2016] [Indexed: 11/20/2022] Open
Abstract
Influenza antigenic and genetic characterisation data are crucial for influenza vaccine composition decision making. Previously, aggregate data were reported to the European Centre for Disease Prevention and Control by European Union/European Economic Area (EU/EEA) countries. A system for collecting case-specific influenza antigenic and genetic characterisation data was established for the 2013/14 influenza season. In a pilot study, 11 EU/EEA countries reported through the new mechanism. We demonstrated feasibility of reporting strain-based antigenic and genetic data and ca 10% of influenza virus-positive specimens were selected for further characterisation. Proportions of characterised virus (sub)types were similar to influenza virus circulation levels. The main genetic clades were represented by A/StPetersburg/27/2011(H1N1)pdm09 and A/Texas/50/2012(H3N2). A(H1N1)pdm09 viruses were more prevalent in age groups (by years) < 1 (65%; p = 0.0111), 20-39 (50%; p = 0.0046) and 40-64 (55%; p = 0.00001) while A(H3N2) viruses were most prevalent in those ≥ 65 years (62%*; p = 0.0012). Hospitalised patients in the age groups 6-19 years (67%; p = 0.0494) and ≥ 65 years (52%; p = 0.0005) were more frequently infected by A/Texas/50/2012 A(H3N2)-like viruses compared with hospitalised cases in other age groups. Strain-based reporting enabled deeper understanding of influenza virus circulation among hospitalised patients and substantially improved the reporting of virus characterisation data. Therefore, strain-based reporting of readily available data is recommended to all reporting countries within the EU/EEA.
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MESH Headings
- Adolescent
- Adult
- Age Distribution
- Aged
- Child
- Child, Preschool
- Epidemiological Monitoring
- Europe/epidemiology
- European Union
- Feasibility Studies
- Hemagglutination Inhibition Tests
- Hospitalization/statistics & numerical data
- Humans
- Influenza A Virus, H1N1 Subtype/genetics
- Influenza A Virus, H1N1 Subtype/immunology
- Influenza A Virus, H1N1 Subtype/isolation & purification
- Influenza A Virus, H3N2 Subtype/genetics
- Influenza A Virus, H3N2 Subtype/immunology
- Influenza A Virus, H3N2 Subtype/isolation & purification
- Influenza Vaccines/administration & dosage
- Influenza Vaccines/immunology
- Influenza, Human/epidemiology
- Influenza, Human/prevention & control
- Influenza, Human/virology
- Middle Aged
- RNA, Viral/genetics
- Seasons
- Sentinel Surveillance
- Sequence Analysis, DNA
- Sex Distribution
- Vaccination/statistics & numerical data
- Young Adult
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Affiliation(s)
- Eeva Broberg
- European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden
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8
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Interim estimates of divergence date and vaccine strain match of human influenza A(H3N2) virus from systematic influenza surveillance (2010-2015) in Hangzhou, southeast of China. Int J Infect Dis 2015; 40:17-24. [PMID: 26417878 DOI: 10.1016/j.ijid.2015.09.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Revised: 09/17/2015] [Accepted: 09/19/2015] [Indexed: 11/21/2022] Open
Abstract
OBJECTIVES In the post-pandemic period 2010-2015, seasonal influenza A(H3N2) virus predominated in Hangzhou, southeast of China, with an increased activity and semi-annual seasons. This study utilized HA virus gene segment sequences to analyze the divergence date and vaccine strain match of human influenza A(H3N2) virus from systematic influenza surveillance in Hangzhou. METHODS Virological and serological analyses of 124 representative A(H3N2) viruses from prospective studies of systematic surveillance samples were conducted to quantify the genetic and antigenic characteristics and their vaccine strain match. RESULTS Bayesian phylogenetic inference showed that two separate subgroups 3C.3 and 3C.2 probably diverged from group 3C in early 2012 and then evolved into groups 3C.3a and 3C.2a, respectively, in the 2014/15 influenza season. Furthermore, high amino acid substitution rates of the HA1 subunit were found in A(H3N2) group 3C.2a variants, indicating that increased antigenic drift of A(H3N2) group 3C.2a virus is associated with a vaccine mismatch to the 2015/16 vaccine reference strain Switzerland/9715293/2013 (group 3C.3a). CONCLUSIONS A portion of the group 3C.2a isolates are not covered by the current A(H3N2) vaccine strain. These findings offer insights into the emergence of group 3C.2a variants with epidemic potential in the imminent influenza seasons.
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9
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Lee HK, Tang JWT, Loh TP, Oon LLE, Koay ESC. Predicting clinical severity based on substitutions near epitope A of influenza A/H3N2. INFECTION GENETICS AND EVOLUTION 2015; 34:292-7. [PMID: 26118307 DOI: 10.1016/j.meegid.2015.06.025] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Revised: 06/15/2015] [Accepted: 06/25/2015] [Indexed: 01/03/2023]
Abstract
Epitopes are the main targets for specific antibodies in the host defense systems. Recent studies have shown that amino acid (aa) substitutions located within the influenza A/H3N2 hemagglutinin 1 (HA1) epitopes A-E, particularly in A and B, result in antigenic drift. Viruses with such drift mutations may have resulted in more severe influenza-related illness during influenza epidemics between late 2012 and early 2015. We sought to quantify vaccine mismatches in epitopes A-E of the HA1 protein, and correlate these with the severity of the patient's illness. The influenza A/H3N2 clinical samples were collected between April 2009 and November 2013 (n=206). Patients were clinically stratified into groups with mild, moderate, and severe influenza-like illness (ILI). The impact of the number of aa mismatches in each of epitopes A-E, gender, age groups (⩽18, 19-64, ⩾65 years), and comorbidities on the likelihood that patients would suffer moderate and/or severe ILI due to influenza A/H3N2 infection were assessed. A higher number of aa mismatches in epitope A between the vaccine and locally circulating viruses correlated with more severe influenza infection, although this correlation was most significant with pre-existing comorbidities. A practical application of this finding would be to monitor patients (especially those in high-risk groups) infected with such viruses more closely, as they are at increased risk of developing more serious disease. Epidemiologically, it was of interest to note that viruses from subclade 3A of Victoria/208 strain were not detected in Singapore between 2009 and 2012. By contrast, these viruses were detected at a prevalence of up to 40% in the 2011-2012 influenza seasons in other regions of the Northern and Southern hemispheres. Such findings support the rationale for more regionally customized seasonal influenza vaccine compositions to optimize the protection of the population against locally circulating virus strains.
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Affiliation(s)
- Hong Kai Lee
- Department of Pathology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Department of Laboratory Medicine, National University Hospital, National University Health System, Singapore
| | - Julian Wei-Tze Tang
- Clinical Microbiology, University Hospitals of Leicester NHS Trust, Leicester, United Kingdom.
| | - Tze Ping Loh
- Department of Laboratory Medicine, National University Hospital, National University Health System, Singapore
| | | | - Evelyn Siew-Chuan Koay
- Department of Pathology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Department of Laboratory Medicine, National University Hospital, National University Health System, Singapore.
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