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An inactivated Ross River virus vaccine is well tolerated and immunogenic in an adult population in a randomized phase 3 trial. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2014; 22:267-73. [PMID: 25540268 DOI: 10.1128/cvi.00546-14] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Ross River virus (RRV) is endemic in Australia and several South Pacific Islands. More than 90,000 cases of RRV disease, which is characterized by debilitating polyarthritis, were reported in Australia in the last 20 years. There is no vaccine available to prevent RRV disease. A phase 3 study was undertaken at 17 sites in Australia to investigate the safety and immunogenicity of an inactivated whole-virus Vero cell culture-derived RRV vaccine in 1,755 healthy younger adults aged 16 to 59 years and 209 healthy older adults aged ≥60 years. Participants received a 2.5-μg dose of Al(OH)(3)-adjuvanted RRV vaccine, with a second and third dose after 3 weeks and 6 months, respectively. Vaccine-induced RRV-specific neutralizing and total IgG antibody titers were measured after each immunization. Vaccine safety was monitored over the entire study period. The vaccine was safe and well-tolerated after each vaccination. No cases of arthritis resembling RRV disease were reported. The most frequently reported systemic reactions were headache, fatigue, and malaise; the most frequently reported injection site reactions were tenderness and pain. After the third immunization, 91.5% of the younger age group and 76.0% of the older age group achieved neutralizing antibody titers of ≥1:10; 89.1% of the younger age group and 70.9% of the older age group achieved enzyme-linked immunosorbent assay (ELISA) titers of ≥11 PanBio units. A whole-virus Vero cell culture-derived RRV vaccine is well tolerated in an adult population and induces antibody titers associated with protection from RRV disease in the majority of individuals. (This study is registered at www.clinicaltrials.gov under registration no. NCT01242670.).
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Remoli ME, Marchi A, Fortuna C, Benedetti E, Minelli G, Fiorentini C, Mel R, Venturi G, Ciufolini MG. Anti-tick-borne encephalitis (TBE) virus neutralizing antibodies dynamics in natural infections versus vaccination. Pathog Dis 2014; 73:1-3. [DOI: 10.1093/femspd/ftu002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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103
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Pierson TC, Diamond MS. A game of numbers: the stoichiometry of antibody-mediated neutralization of flavivirus infection. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2014; 129:141-66. [PMID: 25595803 DOI: 10.1016/bs.pmbts.2014.10.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The humoral response contributes to the protection against viral pathogens. Although antibodies have the potential to inhibit viral infections via several mechanisms, an ability to neutralize viruses directly may be particularly important. Neutralizing antibody titers are commonly used as predictors of protection from infection, especially in the context of vaccine responses and immunity. Despite the simplicity of the concept, how antibody binding results in virus inactivation is incompletely understood despite decades of research. Flaviviruses have been an attractive system in which to seek a structural and quantitative understanding of how antibody interactions with virions modulate infection because of the contribution of antibodies to both protection and pathogenesis. This review will present a stoichiometric model of antibody-mediated neutralization of flaviviruses and discuss how these concepts can inform the development of vaccines and antibody-based therapeutics.
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Affiliation(s)
- Theodore C Pierson
- Viral Pathogenesis Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA.
| | - Michael S Diamond
- Departments of Medicine, Molecular Microbiology, Pathology & Immunology, Center for Human Immunology and Immunotherapy Programs, Washington University School of Medicine, St. Louis, Missouri, USA.
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104
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Dorko E, Rimárová K, Kizek P, Stebnický M, Zákutná Ľ. Increasing Incidence of Tick-Borne Encephalitis and Its Importance in the Slovak Republic. Cent Eur J Public Health 2014; 22:277-81. [DOI: 10.21101/cejph.a3939] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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105
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Šmit R, Postma MJ. Review of tick-borne encephalitis and vaccines: clinical and economical aspects. Expert Rev Vaccines 2014; 14:737-47. [DOI: 10.1586/14760584.2015.985661] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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106
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Variation of the specificity of the human antibody responses after tick-borne encephalitis virus infection and vaccination. J Virol 2014; 88:13845-57. [PMID: 25253341 DOI: 10.1128/jvi.02086-14] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Tick-borne encephalitis (TBE) virus is an important human-pathogenic flavivirus endemic in large parts of Europe and Central and Eastern Asia. Neutralizing antibodies specific for the viral envelope protein E are believed to mediate long-lasting protection after natural infection and vaccination. To study the specificity and individual variation of human antibody responses, we developed immunoassays with recombinant antigens representing viral surface protein domains and domain combinations. These allowed us to dissect and quantify antibody populations of different fine specificities in sera of TBE patients and vaccinees. Postinfection and postvaccination sera both displayed strong individual variation of antibody titers as well as the relative proportions of antibodies to different domains of E, indicating that the immunodominance patterns observed were strongly influenced by individual-specific factors. The contributions of these antibody populations to virus neutralization were quantified by serum depletion analyses and revealed a significantly biased pattern. Antibodies to domain III, in contrast to what was found in mouse immunization studies with TBE and other flaviviruses, did not play any role in the human neutralizing antibody response, which was dominated by antibodies to domains I and II. Importantly, most of the neutralizing activity could be depleted from sera by a dimeric soluble form of the E protein, which is the building block of the icosahedral herringbone-like shell of flaviviruses, suggesting that antibodies to more complex quaternary epitopes involving residues from adjacent dimers play only a minor role in the total response to natural infection and vaccination in humans. IMPORTANCE Tick-borne encephalitis (TBE) virus is a close relative of yellow fever, dengue, Japanese encephalitis, and West Nile viruses and distributed in large parts of Europe and Central and Eastern Asia. Antibodies to the viral envelope protein E prevent viral attachment and entry into cells and thus mediate virus neutralization and protection from disease. However, the fine specificity and individual variation of neutralizing antibody responses are currently not known. We have therefore developed new in vitro assays for dissecting the antibody populations present in blood serum and determining their contribution to virus neutralization. In our analysis of human postinfection and postvaccination sera, we found an extensive variation of the antibody populations present in sera, indicating substantial influences of individual-specific factors that control the specificity of the antibody response. Our study provides new insights into the immune response to an important human pathogen that is of relevance for the design of novel vaccines.
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107
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Lani R, Moghaddam E, Haghani A, Chang LY, AbuBakar S, Zandi K. Tick-borne viruses: a review from the perspective of therapeutic approaches. Ticks Tick Borne Dis 2014; 5:457-65. [PMID: 24907187 DOI: 10.1016/j.ttbdis.2014.04.001] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Revised: 03/07/2014] [Accepted: 04/01/2014] [Indexed: 12/30/2022]
Abstract
Several important human diseases worldwide are caused by tick-borne viruses. These diseases have become important public health concerns in recent years. The tick-borne viruses that cause diseases in humans mainly belong to 3 families: Bunyaviridae, Flaviviridae, and Reoviridae. In this review, we focus on therapeutic approaches for several of the more important tick-borne viruses from these 3 families. These viruses are Crimean-Congo hemorrhagic fever virus (CCHF) and the newly discovered tick-borne phleboviruses, known as thrombocytopenia syndromevirus (SFTSV), Heartland virus and Bhanja virus from the family Bunyaviridae, tick-borne encephalitis virus (TBEV), Powassan virus (POWV), Louping-ill virus (LIV), Omsk hemorrhagic fever virus (OHFV), Kyasanur Forest disease virus (KFDV), and Alkhurma hemorrhagic fever virus (AHFV) from the Flaviviridae family. To date, there is no effective antiviral drug available against most of these tick-borne viruses. Although there is common usage of antiviral drugs such as ribavirin for CCHF treatment in some countries, there are concerns that ribavirin may not be as effective as once thought against CCHF. Herein, we discuss also the availability of vaccines for the control of these viral infections. The lack of treatment and prevention approaches for these viruses is highlighted, and we hope that this review may increase public health awareness with regard to the threat posed by this group of viruses.
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Affiliation(s)
- Rafidah Lani
- Tropical Infectious Disease Research and Education Centre (TIDREC), Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Ehsan Moghaddam
- Tropical Infectious Disease Research and Education Centre (TIDREC), Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Amin Haghani
- Department of Environmental and Occupational Health, Faculty of Medicine and Health Sciences, University Putra Malaysia, Malaysia
| | - Li-Yen Chang
- Tropical Infectious Disease Research and Education Centre (TIDREC), Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Sazaly AbuBakar
- Tropical Infectious Disease Research and Education Centre (TIDREC), Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia
| | - Keivan Zandi
- Tropical Infectious Disease Research and Education Centre (TIDREC), Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
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108
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Yu C, Achazi K, Möller L, Schulzke JD, Niedrig M, Bücker R. Tick-borne encephalitis virus replication, intracellular trafficking, and pathogenicity in human intestinal Caco-2 cell monolayers. PLoS One 2014; 9:e96957. [PMID: 24820351 PMCID: PMC4018392 DOI: 10.1371/journal.pone.0096957] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Accepted: 04/13/2014] [Indexed: 12/27/2022] Open
Abstract
Tick-borne encephalitis virus (TBEV) is one of the most important vector-borne viruses in Europe and Asia. Its transmission mainly occurs by the bite of an infected tick. However, consuming milk products from infected livestock animals caused TBEV cases. To better understand TBEV transmission via the alimentary route, we studied viral infection of human intestinal epithelial cells. Caco-2 cells were used to investigate pathological effects of TBEV infection. TBEV-infected Caco-2 monolayers showed morphological changes including cytoskeleton rearrangements and cytoplasmic vacuolization. Ultrastructural analysis revealed dilatation of the rough endoplasmic reticulum and further enlargement to TBEV containing caverns. Caco-2 monolayers maintained an intact epithelial barrier with stable transepithelial electrical resistance (TER) during early stage of infection. Concomitantly, viruses were detected in the basolateral medium, implying a transcytosis pathway. When Caco-2 cells were pre-treated with inhibitors of cellular pathways of endocytosis TBEV cell entry was efficiently blocked, suggesting that actin filaments (Cytochalasin) and microtubules (Nocodazole) are important for PI3K-dependent (LY294002) virus endocytosis. Moreover, experimental fluid uptake assay showed increased intracellular accumulation of FITC-dextran containing vesicles. Immunofluorescence microscopy revealed co-localization of TBEV with early endosome antigen-1 (EEA1) as well as with sorting nexin-5 (SNX5), pointing to macropinocytosis as trafficking mechanism. In the late phase of infection, further evidence was found for translocation of virus via the paracellular pathway. Five days after infection TER was slightly decreased. Epithelial barrier integrity was impaired due to increased epithelial apoptosis, leading to passive viral translocation. These findings illuminate pathomechanisms in TBEV infection of human intestinal epithelial cells and viral transmission via the alimentary route.
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Affiliation(s)
- Chao Yu
- Centre for Biological Threats and Special Pathogens, ZBS 1: Highly Pathogenic Viruses, Robert Koch Institute, Berlin, Germany
| | - Katharina Achazi
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Lars Möller
- Centre for Biological Threats and Special Pathogens, ZBS 4: Advanced Light and Electron Microscopy, Robert Koch Institute, Berlin, Germany
| | - Joerg D. Schulzke
- Department of Gastroenterology, Infectious Diseases and Rheumatology, Division of Nutritional Medicine, Charité - Universitätsmedizin Berlin, Campus Benjamin Franklin, Berlin, German
- * E-mail:
| | - Matthias Niedrig
- Centre for Biological Threats and Special Pathogens, ZBS 1: Highly Pathogenic Viruses, Robert Koch Institute, Berlin, Germany
| | - Roland Bücker
- Department of Gastroenterology, Infectious Diseases and Rheumatology, Division of Nutritional Medicine, Charité - Universitätsmedizin Berlin, Campus Benjamin Franklin, Berlin, German
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109
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Wichtige, durch Vektoren übertragene Infektionskrankheiten beim Menschen in Deutschland. Bundesgesundheitsblatt Gesundheitsforschung Gesundheitsschutz 2014; 57:557-67. [DOI: 10.1007/s00103-013-1925-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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110
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Abstract
UNLABELLED The production of neutralizing antibodies (NAbs) is a correlate of protection for many human vaccines, including currently licensed vaccines against flaviviruses. NAbs are typically measured using a plaque reduction neutralization test (PRNT). Despite its extensive use, parameters that impact the performance of the PRNT have not been investigated from a mechanistic perspective. The results of a recent phase IIb clinical trial of a tetravalent dengue virus (DENV) vaccine suggest that NAbs, as measured using a PRNT performed with Vero cells, do not correlate with protection. This surprising finding highlights the importance of understanding how well the PRNT captures the complexity of the NAb response to DENV. In this study, we demonstrated that the structural heterogeneity of flaviviruses arising from inefficient virion maturation impacts the results of neutralization assays in a cell type-dependent manner. Neutralization titers of several monoclonal antibodies were significantly reduced when assayed on Vero cells compared to Raji cells expressing DC-SIGNR. This pattern can be explained by differences in the efficiency with which partially mature flaviviruses attach to each cell type, rather than a differential capacity of antibody to block infection. Vero cells are poorly permissive to the fraction of virions that are most sensitive to neutralization. Analysis of sera from recipients of live-attenuated monovalent DENV vaccine candidates revealed a strong correlation between the sensitivity of serum antibodies to the maturation state of DENV and cell type-dependent patterns of neutralization. Cross-reactive patterns of neutralization may be underrepresented by the "gold-standard" PRNT that employs Vero cells. IMPORTANCE Cell type-dependent patterns of neutralization describe a differential capacity of antibodies to inhibit virus infection when assayed on multiple cellular substrates. In this study, we established a link between antibodies that neutralize infection in a cell type-dependent fashion and those sensitive to the maturation state of the flavivirus virion. We demonstrated that cell type-dependent neutralization reflects a differential capacity to measure neutralization of viruses that are incompletely mature. Partially mature virions that most efficiently bind maturation state-sensitive antibodies are poorly represented by assays typically used in support of flavivirus vaccine development. The selection of cellular substrate for neutralization assays may significantly impact evaluation of the neutralization potency of the polyclonal response. These data suggest that current assays do not adequately capture the full complexity of the neutralizing antibody response and may hinder the identification of correlates of protection following flavivirus vaccination.
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111
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Schuler M, Zimmermann H, Altpeter E, Heininger U. Epidemiology of tick-borne encephalitis in Switzerland, 2005 to 2011. Euro Surveill 2014; 19. [DOI: 10.2807/1560-7917.es2014.19.13.20756] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Binary file ES_Abstracts_Final_ECDC.txt matches
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Affiliation(s)
- M Schuler
- Division of Infectious Diseases and Vaccines, University Children’s Hospital (UKBB), Switzerland
| | - H Zimmermann
- Division of Transmissible Diseases, Federal Office of Public Health (FOPH), Berne, Switzerland
| | - E Altpeter
- Division of Transmissible Diseases, Federal Office of Public Health (FOPH), Berne, Switzerland
| | - U Heininger
- Division of Infectious Diseases and Vaccines, University Children’s Hospital (UKBB), Switzerland
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112
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Schosser R, Reichert A, Mansmann U, Unger B, Heininger U, Kaiser R. Irregular tick-borne encephalitis vaccination schedules: The effect of a single catch-up vaccination with FSME-IMMUN. A prospective non-interventional study. Vaccine 2014; 32:2375-81. [DOI: 10.1016/j.vaccine.2014.01.072] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Revised: 01/16/2014] [Accepted: 01/28/2014] [Indexed: 12/30/2022]
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113
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Stefanoff P, Orlíková H, Príkazský V, Beneš Č, Rosińska M. Cross-Border Surveillance Differences: Tick-Borne Encephalitis and Lyme Borreliosis in the Czech Republic and Poland, 1999-2008. Cent Eur J Public Health 2014; 22:54-9. [DOI: 10.21101/cejph.a3937] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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114
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Wang HJ, Li XF, Ye Q, Li SH, Deng YQ, Zhao H, Xu YP, Ma J, Qin ED, Qin CF. Recombinant chimeric Japanese encephalitis virus/tick-borne encephalitis virus is attenuated and protective in mice. Vaccine 2014; 32:949-56. [DOI: 10.1016/j.vaccine.2013.12.050] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 11/14/2013] [Accepted: 12/18/2013] [Indexed: 12/30/2022]
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115
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Arnež M, Avšič-Županc T. Tick-borne encephalitis in children: an update on epidemiology and diagnosis. Expert Rev Anti Infect Ther 2014; 7:1251-60. [DOI: 10.1586/eri.09.99] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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116
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117
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118
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VanBlargan LA, Mukherjee S, Dowd KA, Durbin AP, Whitehead SS, Pierson TC. The type-specific neutralizing antibody response elicited by a dengue vaccine candidate is focused on two amino acids of the envelope protein. PLoS Pathog 2013; 9:e1003761. [PMID: 24348242 PMCID: PMC3857832 DOI: 10.1371/journal.ppat.1003761] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Accepted: 09/27/2013] [Indexed: 11/18/2022] Open
Abstract
Dengue viruses are mosquito-borne flaviviruses that circulate in nature as four distinct serotypes (DENV1-4). These emerging pathogens are responsible for more than 100 million human infections annually. Severe clinical manifestations of disease are predominantly associated with a secondary infection by a heterotypic DENV serotype. The increased risk of severe disease in DENV-sensitized populations significantly complicates vaccine development, as a vaccine must simultaneously confer protection against all four DENV serotypes. Eliciting a protective tetravalent neutralizing antibody response is a major goal of ongoing vaccine development efforts. However, a recent large clinical trial of a candidate live-attenuated DENV vaccine revealed low protective efficacy despite eliciting a neutralizing antibody response, highlighting the need for a better understanding of the humoral immune response against dengue infection. In this study, we sought to identify epitopes recognized by serotype-specific neutralizing antibodies elicited by monovalent DENV1 vaccination. We constructed a panel of over 50 DENV1 structural gene variants containing substitutions at surface-accessible residues of the envelope (E) protein to match the corresponding DENV2 sequence. Amino acids that contribute to recognition by serotype-specific neutralizing antibodies were identified as DENV mutants with reduced sensitivity to neutralization by DENV1 immune sera, but not cross-reactive neutralizing antibodies elicited by DENV2 vaccination. We identified two mutations (E126K and E157K) that contribute significantly to type-specific recognition by polyclonal DENV1 immune sera. Longitudinal and cross-sectional analysis of sera from 24 participants of a phase I clinical study revealed a markedly reduced capacity to neutralize a E126K/E157K DENV1 variant. Sera from 77% of subjects recognized the E126K/E157K DENV1 variant and DENV2 equivalently (<3-fold difference). These data indicate the type-specific component of the DENV1 neutralizing antibody response to vaccination is strikingly focused on just two amino acids of the E protein. This study provides an important step towards deconvoluting the functional complexity of DENV serology following vaccination.
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Affiliation(s)
- Laura A. VanBlargan
- Viral Pathogenesis Section, Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Swati Mukherjee
- Viral Pathogenesis Section, Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Kimberly A. Dowd
- Viral Pathogenesis Section, Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Anna P. Durbin
- Johns Hopkins School of Public Health, Baltimore, Maryland, United States of America
| | - Stephen S. Whitehead
- Laboratory of Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Theodore C. Pierson
- Viral Pathogenesis Section, Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
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119
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Beck C, Jimenez-Clavero MA, Leblond A, Durand B, Nowotny N, Leparc-Goffart I, Zientara S, Jourdain E, Lecollinet S. Flaviviruses in Europe: complex circulation patterns and their consequences for the diagnosis and control of West Nile disease. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2013; 10:6049-83. [PMID: 24225644 PMCID: PMC3863887 DOI: 10.3390/ijerph10116049] [Citation(s) in RCA: 124] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Revised: 10/24/2013] [Accepted: 10/29/2013] [Indexed: 12/11/2022]
Abstract
In Europe, many flaviviruses are endemic (West Nile, Usutu, tick-borne encephalitis viruses) or occasionally imported (dengue, yellow fever viruses). Due to the temporal and geographical co-circulation of flaviviruses in Europe, flavivirus differentiation by diagnostic tests is crucial in the adaptation of surveillance and control efforts. Serological diagnosis of flavivirus infections is complicated by the antigenic similarities among the Flavivirus genus. Indeed, most flavivirus antibodies are directed against the highly immunogenic envelope protein, which contains both flavivirus cross-reactive and virus-specific epitopes. Serological assay results should thus be interpreted with care and confirmed by comparative neutralization tests using a panel of viruses known to circulate in Europe. However, antibody cross-reactivity could be advantageous in efforts to control emerging flaviviruses because it ensures partial cross-protection. In contrast, it might also facilitate subsequent diseases, through a phenomenon called antibody-dependent enhancement mainly described for dengue virus infections. Here, we review the serological methods commonly used in WNV diagnosis and surveillance in Europe. By examining past and current epidemiological situations in different European countries, we present the challenges involved in interpreting flavivirus serological tests and setting up appropriate surveillance programs; we also address the consequences of flavivirus circulation and vaccination for host immunity.
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Affiliation(s)
- Cécile Beck
- UMR1161 Virologie INRA, ANSES, ENVA, EU-RL on equine West Nile disease, Animal Health Laboratory, ANSES, Maisons-Alfort 94704, France; E-Mails: (C.B.); (S.Z.)
| | | | - Agnès Leblond
- Département Hippique, VetAgroSup, Marcy l’Etoile 69280, France; E-Mail:
- UR346, INRA, Saint Genès Champanelle 63122, France; E-Mail:
| | - Benoît Durand
- Epidemiology Unit, Animal Health Laboratory, ANSES, Maisons-Alfort 94704, France; E-Mail:
| | - Norbert Nowotny
- Viral Zoonoses, Emerging and Vector-Borne Infections Group, Institute of Virology, University of Veterinary Medicine Vienna, Vienna 1210, Austria; E-Mail:
- Department of Microbiology and Immunology, College of Medicine and Health Sciences, Sultan Qaboos University, Muscat 123, Sultanate of Oman
| | | | - Stéphan Zientara
- UMR1161 Virologie INRA, ANSES, ENVA, EU-RL on equine West Nile disease, Animal Health Laboratory, ANSES, Maisons-Alfort 94704, France; E-Mails: (C.B.); (S.Z.)
| | - Elsa Jourdain
- UR346, INRA, Saint Genès Champanelle 63122, France; E-Mail:
| | - Sylvie Lecollinet
- UMR1161 Virologie INRA, ANSES, ENVA, EU-RL on equine West Nile disease, Animal Health Laboratory, ANSES, Maisons-Alfort 94704, France; E-Mails: (C.B.); (S.Z.)
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120
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Possible future monoclonal antibody (mAb)-based therapy against arbovirus infections. BIOMED RESEARCH INTERNATIONAL 2013; 2013:838491. [PMID: 24058915 PMCID: PMC3766601 DOI: 10.1155/2013/838491] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Revised: 07/05/2013] [Accepted: 07/11/2013] [Indexed: 11/17/2022]
Abstract
More than 150 arboviruses belonging to different families are known to infect humans, causing endemic infections as well as epidemic outbreaks. Effective vaccines to limit the occurrence of some of these infections have been licensed, while for the others several new immunogens are under development mostly for their improvements concerning safety and effectiveness profiles. On the other hand, specific and effective antiviral drugs are not yet available, posing an urgent medical need in particular for emergency cases. Neutralizing monoclonal antibodies (mAbs) have been demonstrated to be effective in the treatment of several infectious diseases as well as in preliminary in vitro and in vivo models of arbovirus-related infections. Given their specific antiviral activity as well-tolerated molecules with limited side effects, mAbs could represent a new therapeutic approach for the development of an effective treatment, as well as useful tools in the study of the host-virus interplay and in the development of more effective immunogens. However, before their use as candidate therapeutics, possible hurdles (e.g., Ab-dependent enhancement of infection, occurrence of viral escape variants) must be carefully evaluated. In this review are described the main arboviruses infecting humans and candidate mAbs to be possibly used in a future passive immunotherapy.
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121
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Abstract
PURPOSE OF REVIEW Vector-borne diseases (VBDs) are difficult to prevent and control because it is hard to predict the complex habits of mosquitoes, ticks and fleas; most vector-borne viruses or bacteria infect animals as well as humans, which further adds to this difficulty. Thus, prevention is the best protection against VBD. RECENT FINDINGS Vaccines are available for yellow fever, Japanese encephalitis and tick-borne encephalitis and several vaccines are in clinical trials for dengue fever. Antimalarial intermittent preventive therapy (sulfadoxine-pyrimethamine) and insecticide-treated mosquito nets are associated with a decreased risk of neonatal mortality and lower birth-weight. Permethrin-impregnated clothing for the prevention of tick bites has been shown effective in reducing tick bites. SUMMARY Much progress has been made in terms of development of preventive vaccines and medicines, but there is more work that needs to be done. Efforts still need to continue on raising awareness for prevention of VBD.
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122
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Unger B, Barrett PN. Tick-borne encephalitis vaccines. Intern Med J 2013; 43:838-9. [DOI: 10.1111/imj.12189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Accepted: 04/08/2013] [Indexed: 11/29/2022]
Affiliation(s)
- B. Unger
- Baxter Innovations GmbH; Vienna; Austria
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123
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Correlation of TBE incidence with red deer and roe deer abundance in Slovenia. PLoS One 2013; 8:e66380. [PMID: 23776668 PMCID: PMC3679065 DOI: 10.1371/journal.pone.0066380] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Accepted: 05/06/2013] [Indexed: 12/30/2022] Open
Abstract
Tick-borne encephalitis (TBE) is a virus infection which sometimes causes human disease. The TBE virus is found in ticks and certain vertebrate tick hosts in restricted endemic localities termed TBE foci. The formation of natural foci is a combination of several factors: the vectors, a suitable and numerous enough number of hosts and in a habitat with suitable vegetation and climate. The present study investigated the influence of deer on the incidence of tick-borne encephalitis. We were able to obtain data from deer culls. Using this data, the abundance of deer was estimated and temporal and spatial analysis was performed. The abundance of deer has increased in the past decades, as well as the incidence of tick-borne encephalitis. Temporal analysis confirmed a correlation between red deer abundance and tick-borne encephalitis occurrence. Additionally, spatial analysis established, that in areas with high incidence of tick-borne encephalitis red deer density is higher, compared to areas with no or few human cases of tick-borne encephalitis. However, such correlation could not be confirmed between roe deer density and the incidence of tick-borne encephalitis. This is presumably due to roe deer density being above a certain threshold so that availability of tick reproduction hosts has no apparent effect on ticks' host finding and consequently may not be possible to correlate with incidence of human TBE.
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124
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Grgič-Vitek M. Estimating vaccination coverage against tick-borne encephalitis: comment on: Košnik IG, Lah AK. A campaign to increase the vaccination rate in a highly endemic tick-borne encephalitis region of Slovenia. Vaccine 2013;31(5):732-4. Vaccine 2013; 32:2944. [PMID: 23747455 DOI: 10.1016/j.vaccine.2013.05.093] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Revised: 05/20/2013] [Accepted: 05/22/2013] [Indexed: 11/19/2022]
Affiliation(s)
- Marta Grgič-Vitek
- National Institute of Public Health, Trubarjeva 2, 1000 Ljubljana, Slovenia.
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125
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Heinz FX, Stiasny K, Holzmann H, Grgic-Vitek M, Kriz B, Essl A, Kundi M. Vaccination and tick-borne encephalitis, central Europe. Emerg Infect Dis 2013; 19:69-76. [PMID: 23259984 PMCID: PMC3557984 DOI: 10.3201/eid1901.120458] [Citation(s) in RCA: 136] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Tick-borne encephalitis is a disease of the brain caused by a virus found in many parts of Europe as well as central and eastern Asia. As the name indicates, the virus is spread by tick bites. The number of people infected each year varies according to complex interactions involving the ticks’environment, the weather, and human socioeconomic and vaccination status. To determine how well vaccine protects against the disease, researchers compared the number of cases in 3 neighboring countries in which vaccination coverage differs but many other factors remain the same: Austria (where more than three quarters of the population are vaccinated) and Slovenia and the Czech Republic (where less than one quarter of the population are vaccinated). They found far fewer cases in Austria, indicating that vaccination is an excellent way to prevent this disease. Tick-borne encephalitis (TBE) is a substantial public health problem in many parts of Europe and Asia. To assess the effect of increasing TBE vaccination coverage in Austria, we compared incidence rates over 40 years for highly TBE-endemic countries of central Europe (Czech Republic, Slovenia, and Austria). For all 3 countries we found extensive annual and longer range fluctuations and shifts in distribution of patient ages, suggesting major variations in the complex interplay of factors influencing risk for exposure to TBE virus. The most distinctive effect was found for Austria, where mass vaccination decreased incidence to ≈16% of that of the prevaccination era. Incidence rates remained high for the nonvaccinated population. The vaccine was effective for persons in all age groups. During 2000–2011 in Austria, ≈4,000 cases of TBE were prevented by vaccination.
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Affiliation(s)
- Franz X Heinz
- Department of Virology, Medical University of Vienna, Vienna, Austria.
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126
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Lantos PM. Lyme disease vaccination: are we ready to try again? THE LANCET. INFECTIOUS DISEASES 2013; 13:643-4. [PMID: 23665340 DOI: 10.1016/s1473-3099(13)70085-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Paul M Lantos
- Department of Internal Medicine, Duke University School of Medicine, Durham, NC 27710, USA.
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127
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Amicizia D, Domnich A, Panatto D, Lai PL, Cristina ML, Avio U, Gasparini R. Epidemiology of tick-borne encephalitis (TBE) in Europe and its prevention by available vaccines. Hum Vaccin Immunother 2013; 9:1163-71. [PMID: 23377671 PMCID: PMC3899155 DOI: 10.4161/hv.23802] [Citation(s) in RCA: 113] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Revised: 01/21/2013] [Accepted: 01/28/2013] [Indexed: 12/30/2022] Open
Abstract
Tick-borne Encephalitis (TBE), which is caused by a Flavivirus, is the most common tick-transmitted disease in Central and Eastern Europe and Russia. Today, TBE is endemic in 27 European countries, and has become an international public health problem. The epidemiology of TBE is changing owing to various factors, such as improvements in diagnosis and case reporting, increased recreational activities in areas populated by ticks, and changes in climatic conditions affecting tick habitats. Vaccination remains the most effective protective measure against TBE for people living in risk zones, occupationally exposed subjects and travelers to endemic areas. The vaccines currently in use are FSME-Immun(®), Encepur(®), EnceVir(®) and TBE vaccine Moscow(®). The numerous studies performed on the efficacy and safety of these vaccines have shown a high level of immunogenicity and an excellent safety profile. Several studies have also shown a high level of cross-protection among strains belonging to different subtypes. In the present paper we attempted to describe the continuously changing epidemiology of TBE in European States and to overview clinical development of available vaccines paying particular attention on cross-protection elicited by the vaccines.
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Affiliation(s)
- Daniela Amicizia
- Department of Health Sciences; University of Genoa; Genoa, Italy
| | | | | | - Piero Luigi Lai
- Department of Health Sciences; University of Genoa; Genoa, Italy
| | | | - Ulderico Avio
- Business Unit Manager Vaccines; Baxter S.p.A.; Rome, Italy
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128
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Diosa-Toro M, Urcuqui-Inchima S, Smit JM. Arthropod-borne flaviviruses and RNA interference: seeking new approaches for antiviral therapy. Adv Virus Res 2013; 85:91-111. [PMID: 23439025 PMCID: PMC7149629 DOI: 10.1016/b978-0-12-408116-1.00004-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Flaviviruses are the most prevalent arthropod-borne viruses worldwide, and nearly half of the 70 Flavivirus members identified are human pathogens. Despite the huge clinical impact of flaviviruses, there is no specific human antiviral therapy available to treat infection with any of the flaviviruses. Therefore, there is a continued search for novel therapies, and this review describes the current knowledge on the usage of RNA interference (RNAi) in combating flavivirus infections. RNAi is a process of sequence-specific gene silencing triggered by double-stranded RNA. Antiviral RNAi strategies against arthropod-borne flaviviruses have been reported and although several hurdles must be overcome to employ this technology in clinical applications, they potentially represent a new therapeutic tool.
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Affiliation(s)
- Mayra Diosa-Toro
- Department of Medical Microbiology, Molecular Virology Section, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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129
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Kollaritsch H, Paulke-Korinek M, Holzmann H, Hombach J, Bjorvatn B, Barrett A. Vaccines and vaccination against tick-borne encephalitis. Expert Rev Vaccines 2013; 11:1103-19. [PMID: 23151167 DOI: 10.1586/erv.12.86] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Tick-borne encephalitis (TBE) is an emerging viral zoonosis and is endemic from Japan, China, Mongolia and Russia, to Central Europe and France. There is no specific treatment and TBE can be fatal. The four licensed prophylactic vaccines are produced according to WHO manufacturing requirements. Large clinical trials and postmarketing surveillance demonstrated safety and efficacy of the two European vaccines. The two Russian vaccines showed their effectiveness in daily use, but limited published data are available on controlled clinical trials. Vaccination recommendations in endemic areas vary significantly. In some countries, public vaccination programs are implemented. The WHO has recently issued recommendations on evidence-based use of TBE vaccines. However, more data are needed regarding safety, efficacy and long-term protection after vaccination.
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Affiliation(s)
- Herwig Kollaritsch
- Department of Specific Prophylaxis and Tropical Medicine, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Kinderspitalgasse 15, Vienna, Austria
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130
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Paulke-Korinek M, Kollaritsch H, Aberle SW, Zwazl I, Schmidle-Loss B, Vécsei A, Kundi M. Sustained low hospitalization rates after four years of rotavirus mass vaccination in Austria. Vaccine 2013; 31:2686-91. [PMID: 23597718 DOI: 10.1016/j.vaccine.2013.04.001] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Revised: 03/15/2013] [Accepted: 04/02/2013] [Indexed: 11/27/2022]
Abstract
This hospital based surveillance study evaluates the effects of the rotavirus mass vaccination program, which was initiated in Austria in August 2007. Since then, incidence rates of rotavirus hospitalizations in children <15 years of age have decreased by 70% and 64% in 2010 and 2011 compared to the pre-vaccination era (2001-2005). Incidence rates were highest in children <90 days of age, highlighting the importance of the early start of active rotavirus immunization. In children between 2 and 3.5 years in 2011, who were in the second and third year after vaccination in the universal mass vaccination program, incidence rates remained low suggesting sustained protection after vaccination up to three years. In the years 2010 and 2011, field effectiveness of the vaccines was between 79% and 96%, depending on the assumptions made for children without information on vaccination history. From genotyping an increase of the prevalence of G2P[4] in children with breakthrough infection (disease despite vaccination) can be suspected. The rate of severe adverse events was 1.3-1.5 per 10(-5) administered doses of rotavirus vaccines and no death, intussusception or Kawasaki disease was reported in 2010 and 2011 following rotavirus vaccination.
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Affiliation(s)
- Maria Paulke-Korinek
- Institute of Specific Prophylaxis and Tropical Medicine, Medical University Vienna, Austria
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131
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Acute Viral Infections of the Central Nervous System in Immunocompetent Adults: Diagnosis and Management. Drugs 2013; 73:131-58. [DOI: 10.1007/s40265-013-0007-5] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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132
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Paulke-Korinek M, Kundi M, Laaber B, Brodtraeger N, Seidl-Friedrich C, Wiedermann U, Kollaritsch H. Factors associated with seroimmunity against tick borne encephalitis virus 10 years after booster vaccination. Vaccine 2013; 31:1293-7. [DOI: 10.1016/j.vaccine.2012.12.075] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Revised: 12/06/2012] [Accepted: 12/24/2012] [Indexed: 11/16/2022]
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133
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Zavadska D, Anca I, André F, Bakir M, Chlibek R, Čižman M, Ivaskeviciene I, Mangarov A, Mészner Z, Pokorn M, Prymula R, Richter D, Salman N, Šimurka P, Tamm E, Tešović G, Urbancikova I, Usonis V. Recommendations for tick-borne encephalitis vaccination from the Central European Vaccination Awareness Group (CEVAG). Hum Vaccin Immunother 2013; 9:362-74. [PMID: 23291941 PMCID: PMC3859759 DOI: 10.4161/hv.22766] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Revised: 10/27/2012] [Accepted: 11/03/2012] [Indexed: 12/13/2022] Open
Abstract
Tick-borne encephalitis (TBE) is a viral neurological zoonotic disease transmitted to humans by ticks or by consumption of unpasteurized dairy products from infected cows, goats, or sheep. TBE is highly endemic in areas of Central and Eastern Europe and Russia where it is a major public health concern. However, it is difficult to diagnose TBE as clinical manifestations tend to be relatively nonspecific and a standardized case definition does not exist across the region. TBE is becoming more important in Europe due to the appearance of new endemic areas. Few Central European Vaccination Awareness Group (CEVAG) member countries have implemented universal vaccination programmes against TBE and vaccination coverage is not considered sufficient to control the disease. When implemented, immunization strategies only apply to risk groups under certain conditions, with no harmonized recommendations available to date across the region. Effective vaccination programmes are essential in preventing the burden of TBE. This review examines the current situation of TBE in CEVAG countries and contains recommendations for the vaccination of children and high-risk groups. For countries at very high risk of TBE infections, CEVAG strongly recommends the introduction of universal TBE vaccination in children > 1 y of age onwards. For countries with a very low risk of TBE, recommendations should only apply to those traveling to endemic areas. Overall, it is generally accepted that each country should be free to make its own decision based on regional epidemiological data and the vaccination calendar, although recommendations should be made, especially for those living in endemic areas.
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Affiliation(s)
- Dace Zavadska
- Department of Pediatrics; Riga Stradins University; Riga, Latvia
| | - Ioana Anca
- Carol Davila University of Medicine and Pharmacy; Institute for Mother and Child Care; Bucharest, Romania
| | | | - Mustafa Bakir
- Department of Pediatrics; Division of Pediatric Infectious Diseases; Marmara University School of Medicine; Istanbul, Turkey
| | - Roman Chlibek
- Faculty of Military Health Sciences; University of Defence; Hradec Kralove, Czech Republic
| | - Milan Čižman
- Department of Infectious Diseases; University Medical Centre; Ljubljana, Slovenia
| | - Inga Ivaskeviciene
- Faculty of Medicine; Vilnius University Clinic of Children’s Diseases; Vilnius, Lithuania
| | | | | | - Marko Pokorn
- Department of Infectious Diseases; University Medical Centre; Ljubljana, Slovenia
| | - Roman Prymula
- Faculty of Military Health Sciences; University of Defence; Hradec Kralove, Czech Republic
- University Hospital; Hradec Kralove, Czech Republic
| | - Darko Richter
- Department of Pediatrics; University Hospital Center; Zagreb, Croatia
| | - Nuran Salman
- Division of Infectious Disease and Clinical Microbiology; University of Istanbul; Istanbul Turkey
| | - Pavol Šimurka
- Pediatric Clinic; Faculty Hospital; University of Trencin; Trenčín, Slovakia
| | - Eda Tamm
- Children’s Clinic of Tartu University Hospital; Tartu, Estonia
| | - Goran Tešović
- Paediatric Infectious Diseases Department; University of Zagreb School of Medicine; Zagreb, Croatia
| | - Ingrid Urbancikova
- Department of Paediatric Infectious Diseases; Children’s Faculty Hospital; Košice, Slovakia
| | - Vytautas Usonis
- Faculty of Medicine; Vilnius University Clinic of Children’s Diseases; Vilnius, Lithuania
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134
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Košnik IG, Lah AK. A campaign to increase the vaccination rate in a highly endemic tick-borne encephalitis region of Slovenia. Vaccine 2013; 31:732-4. [DOI: 10.1016/j.vaccine.2012.12.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Revised: 11/30/2012] [Accepted: 12/02/2012] [Indexed: 12/16/2022]
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135
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Baldovin T, Mel R, Bertoncello C, Carpenè G, Soppelsa F, Giliberti A, Baldo V. Persistence of immunity to tick-borne encephalitis after vaccination and natural infection. J Med Virol 2012; 84:1274-8. [PMID: 22711356 DOI: 10.1002/jmv.23313] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Long-term persistence of immunity was assessed in 66 patients who had contracted tick-borne encephalitis (TBE) and in 126 subjects who had completed primary TBE immunization using a conventional three-dose schedule from 3 to 8 years earlier. Immunity was tested in the subjects stratified by age as follows: ≤40 years (N = 37); 41-60 years (N = 100); and over 60 years (N = 55). Antibody levels decreased significantly with increasing age in the vaccinated cohort by comparison with the individuals who had previously contracted TBE. Consistently higher geometric mean antibody levels were found in the patients infected naturally. When the vaccinated subjects were compared, subjects ≤40 years old had significantly higher antibody levels than either of the older groups. Analyzing immunity to TBE over time revealed a remarkable (50%) decline in seroprotection rates in the vaccinated group at 50 months of follow-up, while stable, high levels persisted in all subjects after natural TBE infection. In the vaccinees over 60 years old, the TBE antibody levels reached 60% at 60 months, and 20% at 70 months of follow-up; in contrast, in the 41-60-year-old group, the antibody levels remained high for 70 months, and then fell rapidly. For people aged <60 years old, booster doses are recommended every 5 years after the fourth dose of vaccine, which should be administered 3 years after primary immunization. In subjects aged 60 years or older, booster doses should be given every 3 years.
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Affiliation(s)
- Tatjana Baldovin
- Department of Molecular Medicine, Institute of Hygiene, University of Padua, Italy.
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136
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Heinz FX, Stiasny K. Flaviviruses and flavivirus vaccines. Vaccine 2012; 30:4301-6. [PMID: 22682286 DOI: 10.1016/j.vaccine.2011.09.114] [Citation(s) in RCA: 195] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2011] [Revised: 09/16/2011] [Accepted: 09/23/2011] [Indexed: 12/28/2022]
Abstract
Several human-pathogenic flaviviruses (including yellow fever, dengue, Japanese encephalitis, West Nile and tick-borne encephalitis viruses) have a significant public health impact in different parts of the world and the potential of emerging in previously non-endemic regions. For some viruses, the structure of the most important immunogen, the envelope protein E, has been determined to atomic resolution by X-ray crystallography, and the architecture of virus particles has been resolved by cryo-electron microscopy. Through the combination of structural and immunological investigations, we now have a detailed understanding of the mechanisms of virus neutralization and antibody-dependent enhancement (ADE) of infectivity at a molecular level. The latter phenomenon has been proposed to play an important role in the immunopathology of severe forms of dengue virus infections (hemorrhagic dengue fever and dengue shock syndrome) and is therefore of special relevance in the context of dengue vaccines. Effective human vaccines are in use for the prophylaxis of yellow fever (live attenuated), Japanese encephalitis (live attenuated and inactivated whole virus), and tick-borne encephalitis (inactivated whole virus). Although dengue is the most important flavivirus with respect to global disease incidence, the development and use of vaccines has been hampered so far by the theoretical risk of vaccine-related adverse events such as immune enhancement of infection and the requirement to induce a long-lasting protective immune response against all four dengue serotypes simultaneously. Currently, several kinds of dengue vaccines are in development, but only one of these candidates (a chimeric dengue-yellow fever live attenuated vaccine) has reached the stage of phase 3 clinical trials.
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Affiliation(s)
- Franz X Heinz
- Department of Virology, Medical University of Vienna, Kinderspitalgasse 15, 1095 Vienna, Austria.
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137
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Stefanoff P, Rosinska M, Samuels S, White DJ, Morse DL, Randolph SE. A national case-control study identifies human socio-economic status and activities as risk factors for tick-borne encephalitis in Poland. PLoS One 2012; 7:e45511. [PMID: 23029063 PMCID: PMC3446880 DOI: 10.1371/journal.pone.0045511] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Accepted: 08/21/2012] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Tick-borne encephalitis (TBE) is endemic to Europe and medically highly significant. This study, focused on Poland, investigated individual risk factors for TBE symptomatic infection. METHODS AND FINDINGS In a nation-wide population-based case-control study, of the 351 TBE cases reported to local health departments in Poland in 2009, 178 were included in the analysis. For controls, of 2704 subjects (matched to cases by age, sex, district of residence) selected at random from the national population register, two were interviewed for each case and a total of 327 were suitable for the analysis. Questionnaires yielded information on potential exposure to ticks during the six weeks (maximum incubation period) preceding disease onset in each case. Independent associations between disease and socio-economic factors and occupational or recreational exposure were assessed by conditional logistic regression, stratified according to residence in known endemic and non-endemic areas. Adjusted population attributable fractions (PAF) were computed for significant variables. In endemic areas, highest TBE risk was associated with spending ≥10 hours/week in mixed forests and harvesting forest foods (adjusted odds ratio 19.19 [95% CI: 1.72-214.32]; PAF 0.127 [0.064-0.193]), being unemployed (11.51 [2.84-46.59]; 0.109 [0.046-0.174]), or employed as a forester (8.96 [1.58-50.77]; 0.053 [0.011-0.100]) or non-specialized worker (5.39 [2.21-13.16]; 0.202 [0.090-0.282]). Other activities (swimming, camping and travel to non-endemic regions) reduced risk. Outside TBE endemic areas, risk was greater for those who spent ≥10 hours/week on recreation in mixed forests (7.18 [1.90-27.08]; 0.191 [0.065-0.304]) and visited known TBE endemic areas (4.65 [0.59-36.50]; 0.058 [-0.007-0.144]), while travel to other non-endemic areas reduced risk. CONCLUSIONS These socio-economic factors and associated human activities identified as risk factors for symptomatic TBE in Poland are consistent with results from previous correlational studies across eastern Europe, and allow public health interventions to be targeted at particularly vulnerable sections of the population.
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Affiliation(s)
- Pawel Stefanoff
- Department of Epidemiology, National Institute of Public Health – National Institute of Hygiene, Warsaw, Poland
| | - Magdalena Rosinska
- Department of Epidemiology, National Institute of Public Health – National Institute of Hygiene, Warsaw, Poland
| | - Steven Samuels
- State University of New York at Albany, School of Public Health, Rensselaer, New York, United States of America
| | - Dennis J. White
- State University of New York at Albany, School of Public Health, Rensselaer, New York, United States of America
- New York State Department of Health, Albany, New York, United States of America
| | - Dale L. Morse
- National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, United States of America
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138
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Smit R. Cost-effectiveness of tick-borne encephalitis vaccination in Slovenian adults. Vaccine 2012; 30:6301-6. [PMID: 22885012 DOI: 10.1016/j.vaccine.2012.07.083] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Revised: 07/26/2012] [Accepted: 07/30/2012] [Indexed: 11/17/2022]
Abstract
BACKGROUND Slovenia is an endemic country with a high incidence rate of tick-borne encephalitis (TBE) and low vaccination coverage. TBE causes high costs for the health care insurances as well as the society due to hospitalization and frequent long term or permanent neurological sequelae. Vaccination is effective and a safe prophylaxis against TBE. OBJECTIVE The purpose of this study was to evaluate the incremental cost-effectiveness ratio (ICER) between vaccination and no vaccination in Slovenia. The results are shown as cost per quality-adjusted life year (QALY) gained from the view of the health care payer and the society. METHODS Based on the natural course of the disease, the Markov model was used for comparing the economic and health outcomes of vaccinated and unvaccinated groups from 18 to 80 years of age. RESULTS The incremental cost-effectiveness ratio from the current Slovenian vaccination programme for FSME-Immun(®) compared to no vaccination amounts to € 15,128 per QALY gained and for Encepur(®) € 20,099 per QALY gained from the view of the health care payer. From the view of the society vaccination is cost saving, mainly due to avoiding the high indirect costs. CONCLUSIONS According to the cost-effectiveness threshold as proposed by the Slovenian Health Council, the current Slovenian vaccination programme against TBE is cost-effective from the health care payer's perspective and also economical from the society's perspective.
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Affiliation(s)
- Renata Smit
- University of Ljubljana, Faculty of Pharmacy, Department of Social Pharmacy, Ljubljana, Slovenia. renata
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139
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Kaiser R. Tick-borne encephalitis: Clinical findings and prognosis in adults. Wien Med Wochenschr 2012; 162:239-43. [DOI: 10.1007/s10354-012-0105-0] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Accepted: 04/19/2012] [Indexed: 01/31/2023]
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140
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Jelinek T. TBE—update on vaccination recommendations for children, adolescents, and adults. Wien Med Wochenschr 2012; 162:248-51. [DOI: 10.1007/s10354-012-0112-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Accepted: 04/17/2012] [Indexed: 12/30/2022]
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141
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Lobigs M, Diamond MS. Feasibility of cross-protective vaccination against flaviviruses of the Japanese encephalitis serocomplex. Expert Rev Vaccines 2012; 11:177-87. [PMID: 22309667 DOI: 10.1586/erv.11.180] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Serological cross-reactivity providing cross-protective immunity between antigenically related viruses is a cornerstone of vaccination. It was the immunological basis for the first human vaccine against smallpox introduced more than 200 years ago, and continues to underpin modern vaccine development as has recently been shown for human papillomavirus vaccines, which confer cross-protection against other oncogenic papillomavirus types not present in the vaccine. Here, we review the feasibility of cross-protective vaccination against an antigenic group of clinically important viruses belonging to the Japanese encephalitis serocomplex in the Flaviviridae family. We will discuss evidence suggesting that 'new generation' flavivirus vaccines may provide effective cross-protective immunity against heterologous Japanese encephalitis serocomplex viruses, and appraise potential risks associated with cross-reactive vaccine immunity. The review will also focus on the structural and mechanistic basis for cross-protective immunity among this group of flaviviruses, which is predominantly mediated by antibodies against a single viral surface protein.
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Affiliation(s)
- Mario Lobigs
- Department of Emerging Pathogens & Vaccines, John Curtin School of Medical Research, The Australian National University, PO Box 334, Canberra, 2600, ACT, Australia.
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142
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Tick-borne encephalitis (TBE): an underestimated risk…still: report of the 14th annual meeting of the International Scientific Working Group on Tick-Borne Encephalitis (ISW-TBE). Ticks Tick Borne Dis 2012; 3:197-201. [PMID: 22765977 DOI: 10.1016/j.ttbdis.2012.03.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Accepted: 03/23/2012] [Indexed: 11/22/2022]
Abstract
Today, the risk of getting tick-borne encephalitis (TBE) is still underestimated in many parts of Europe and worldwide. Therefore, the 14th meeting of the International Scientific Working Group on Tick-Borne Encephalitis (ISW-TBE) - a group of neurologists, general practitioners, clinicians, travel physicians, virologists, pediatricians, and epidemiologists - was held under the title "Tick-borne encephalitis: an underestimated risk…still". Among the discussed issues were: TBE, an underestimated risk in children, a case report in two Dutch travelers, the very emotional report of a tick victim, an overview of the epidemiological situation, investigations to detect new TBE cases in Italy, TBE virus (TBEV) strains circulation in Northern Europe, TBE Program of the European Centre for Disease Prevention and Control (ECDC), efforts to increase the TBE vaccination rate in the Czech Republic, positioning statement of the World Health Organization (WHO), and TBE in dogs. To answer the question raised above: Yes, the risk of getting TBE is underestimated in children and adults, because awareness is still too low. It is still underestimated in several areas of Europe, where, for a lack of human cases, TBEV is thought to be absent. It is underestimated in travelers, because they still do not know enough about the risk, and diagnostic awareness in non-endemic countries is still low.
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143
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Quantitative determination of IgM antibodies reduces the pitfalls in the serodiagnosis of tick-borne encephalitis. J Clin Virol 2012; 54:115-20. [DOI: 10.1016/j.jcv.2012.02.016] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Revised: 02/06/2012] [Accepted: 02/13/2012] [Indexed: 12/12/2022]
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144
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Uzcátegui NY, Sironen T, Golovljova I, Jääskeläinen AE, Välimaa H, Lundkvist Å, Plyusnin A, Vaheri A, Vapalahti O. Rate of evolution and molecular epidemiology of tick-borne encephalitis virus in Europe, including two isolations from the same focus 44 years apart. J Gen Virol 2012; 93:786-796. [DOI: 10.1099/vir.0.035766-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Tick-borne encephalitis virus (TBEV) is a member of the family Flaviviridae. It is transmitted by Ixodes spp. ticks in a cycle involving rodents and small mammals. TBEV has three subtypes: European, Siberian and Far Eastern. The virus causes thousands of cases of meningoencephalitis in Europe annually, with an increasing trend. The increase may be attributed to a complex network of elements, including climatic, environmental and socio-economic factors. In an attempt to understand the evolutionary history and dispersal of TBEV, to existing genetic data we add two novel complete ORF sequences of TBEV strains from northern Europe and the completion of the genome of four others. Moreover, we provide a unique measure for the natural rate of evolution of TBEV by studying two isolations from the same forest on an island in Åland archipelago 44 years apart. For all isolates, we analysed the phylogeny, rate of evolution and probable time of radiation of the different TBEV strains. The results show that the two lineages of TBEV in different Ixodes species have evolved independently for approximately 3300 years. Notably, rapid radiation of TBEV-Eur occurred approximately 300 years ago, without the large-scale geographical clustering observed previously for the Siberian subtype. The measurements from the natural rate of evolution correlated with the estimates done by phylogenetic programs, demonstrating their robustness.
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Affiliation(s)
- Nathalie Y. Uzcátegui
- Infection Biology Research Program, Department of Virology, Haartman Institute, PO Box 21, FI-00014 University of Helsinki, Helsinki, Finland
| | - Tarja Sironen
- Infection Biology Research Program, Department of Virology, Haartman Institute, PO Box 21, FI-00014 University of Helsinki, Helsinki, Finland
| | - Irina Golovljova
- Department of Virology, National Institute for Health Development, EE-11619 Tallinn, Estonia
- Center for Microbiological Preparedness, Swedish Institute for Infectious Disease Control, SE-17182 Solna, Sweden
| | - Anu E. Jääskeläinen
- Infection Biology Research Program, Department of Virology, Haartman Institute, PO Box 21, FI-00014 University of Helsinki, Helsinki, Finland
| | - Hannamari Välimaa
- Department of Virology, Helsinki University Hospital Laboratory (HUSLAB), PO Box 400, FI-00029 HUS, Helsinki, Finland
- Infection Biology Research Program, Department of Virology, Haartman Institute, PO Box 21, FI-00014 University of Helsinki, Helsinki, Finland
| | - Åke Lundkvist
- Center for Microbiological Preparedness, Swedish Institute for Infectious Disease Control, SE-17182 Solna, Sweden
| | - Alexander Plyusnin
- Infection Biology Research Program, Department of Virology, Haartman Institute, PO Box 21, FI-00014 University of Helsinki, Helsinki, Finland
| | - Antti Vaheri
- Department of Virology, Helsinki University Hospital Laboratory (HUSLAB), PO Box 400, FI-00029 HUS, Helsinki, Finland
- Infection Biology Research Program, Department of Virology, Haartman Institute, PO Box 21, FI-00014 University of Helsinki, Helsinki, Finland
| | - Olli Vapalahti
- Department of Basic Veterinary Sciences, Faculty of Veterinary Medicine, PO Box 66, FI-00014 University of Helsinki, Helsinki, Finland
- Department of Virology, Helsinki University Hospital Laboratory (HUSLAB), PO Box 400, FI-00029 HUS, Helsinki, Finland
- Infection Biology Research Program, Department of Virology, Haartman Institute, PO Box 21, FI-00014 University of Helsinki, Helsinki, Finland
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145
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Stiasny K, Aberle JH, Keller M, Grubeck-Loebenstein B, Heinz FX. Age affects quantity but not quality of antibody responses after vaccination with an inactivated flavivirus vaccine against tick-borne encephalitis. PLoS One 2012; 7:e34145. [PMID: 22461903 PMCID: PMC3312914 DOI: 10.1371/journal.pone.0034145] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2011] [Accepted: 02/22/2012] [Indexed: 02/07/2023] Open
Abstract
The impairment of immune functions in the elderly (immunosenescence) results in post-vaccination antibody titers that are significantly lower than in young individuals. It is, however, a controversial question whether also the quality of antibodies declines with age. In this study, we have therefore investigated the age-dependence of functional characteristics of antibody responses induced by vaccination with an inactivated flavivirus vaccine against tick-borne encephalitis (TBE). For this purpose, we quantified TBE virus-specific IgG and neutralizing antibody titers in post-vaccination sera from groups of young and elderly healthy adults and determined antibody avidities and NT/ELISA titer ratios (functional activity). In contrast to the quantitative impairment of antibody production in the elderly, we found no age-related differences in the avidity and functional activity of antibodies induced by vaccination, which also appeared to be independent of the age at primary immunization. There was no correlation between antibody avidity and NT/ELISA ratios suggesting that additional factors affect the quality of polyclonal responses, independent of age. Our work indicates that healthy elderly people are able to produce antibodies in response to vaccination with similar avidity and functional activity as young individuals, albeit at lower titers.
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Affiliation(s)
- Karin Stiasny
- Department of Virology, Medical University of Vienna, Vienna, Austria.
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146
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Degrees of maturity: the complex structure and biology of flaviviruses. Curr Opin Virol 2012; 2:168-75. [PMID: 22445964 DOI: 10.1016/j.coviro.2012.02.011] [Citation(s) in RCA: 166] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Revised: 02/20/2012] [Accepted: 02/22/2012] [Indexed: 11/21/2022]
Abstract
Flaviviruses are small enveloped virions that enter target cells in a pH-dependent fashion. Virus attachment, entry, and membrane fusion are orchestrated by the envelope (E) and pre-membrane (prM) proteins, the two structural proteins displayed on the surface of virions. Flaviviruses assemble as an immature non-infectious form onto which prM and E form trimeric spikes. During egress from infected cells, flaviviruses undergo dramatic structural changes characterized by the formation of a herringbone arrangement of E proteins that lie flat against the surface of the virion and cleavage of the prM protein by the cellular protease furin. The result is a relatively smooth, infectious mature virion. This dynamic process is now understood in structural detail at the atomic level. However, recent studies indicate that many of the virions released from cells share structural features of both immature and mature virus particles. These mosaic partially mature virions are infectious and interact uniquely with target cells and the host immune response. Here, we will discuss recent advances in our understanding of the biology and significance of partially mature flaviviruses.
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147
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Tick-borne encephalitis virus-neutralizing antibodies in different immunoglobulin preparations. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2012; 19:623-5. [PMID: 22379062 DOI: 10.1128/cvi.05705-11] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Patients with primary immunodeficiency (PIDs) depend on the presence of a variety of antibody specificities in intravenous immunoglobulin (IVIG). Using the tick-borne encephalitis virus (TBEV), geographic variability in IVIG antibody content was shown. Care should therefore be exercised when treating PIDs in a given geography, as only locally sourced plasma contains the antibody specificities against the circulating pathogens in the given locality.
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148
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Pediatric tick-borne infections of the central nervous system in an endemic region of Sweden: a prospective evaluation of clinical manifestations. Eur J Pediatr 2012; 171:347-52. [PMID: 21842178 DOI: 10.1007/s00431-011-1542-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2011] [Accepted: 07/26/2011] [Indexed: 12/30/2022]
Abstract
UNLABELLED Tick-borne encephalitis (TBE) and neuroborreliosis (NB) are well-known central nervous system (CNS) infections in children. Childhood tick-borne CNS infections are generally described as mild conditions. However, this view has recently been challenged, and the natural course, including potential sequelae, has been debated. If the diseases present with nonspecific symptoms and signs, some children may elude diagnosis. This study estimates the incidence of symptomatic tick-borne CNS infections in children under medical care and describes the spectrum of manifestations. One hundred twenty-four children with neurologic symptoms attending the Pediatric Emergency Department were included prospectively. Anti-TBE virus and anti-Borrelia serology results were analyzed together with inflammatory parameters in the blood and cerebrospinal fluid. Nearly one fourth of the children with neurologic symptoms were diagnosed with a tick-borne CNS infection (TBE, n = 10 [8%] and NB, n = 21 [16.8%]). In general, these children displayed an indistinct medical history and presented with nonspecific signs such as malaise/fatigue and headache. Diagnosis was based on analysis of acute and convalescent sera. Blood inflammatory parameters were nonspecific and did not contribute to the diagnostics. CONCLUSION Pediatric tick-borne CNS infections are unexpectedly common and should be considered in children with unspecific and unexplained acute CNS-related symptoms.
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149
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Askling H, Vene S, Rombo L, Lindquist L. Immunogenicity of delayed TBE-vaccine booster. Vaccine 2012; 30:499-502. [DOI: 10.1016/j.vaccine.2011.11.061] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2011] [Revised: 11/11/2011] [Accepted: 11/15/2011] [Indexed: 12/30/2022]
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150
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Fritz R, Orlinger KK, Hofmeister Y, Janecki K, Traweger A, Perez-Burgos L, Barrett PN, Kreil TR. Quantitative comparison of the cross-protection induced by tick-borne encephalitis virus vaccines based on European and Far Eastern virus subtypes. Vaccine 2011; 30:1165-9. [PMID: 22178103 DOI: 10.1016/j.vaccine.2011.12.013] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Revised: 11/22/2011] [Accepted: 12/02/2011] [Indexed: 11/15/2022]
Abstract
Tick-borne encephalitis virus (TBEV) is a flavivirus of wide geographic distribution and the causative agent of tick-borne encephalitis (TBE), an infection of the central nervous system. TBE has the highest incidence rate in Russia, where locally produced as well as Western European vaccines for the prevention of TBE are available. The Western European vaccines are based on TBE viruses that belong to the European subtype, while the Russian vaccines are based on Far Eastern subtype viruses. The question of to which extent vaccination with a vaccine based on the European subtype is effective in protecting against the heterologous Far Eastern virus subtype - and vice versa - has not been answered conclusively. Here we immunized mice with TBE vaccines based on European and Far Eastern subtype viruses, and used an unbiased hybrid virus test system to determine cross-neutralizing antibody titers and cross-protective efficacy. All vaccines tested elicited cross-protective responses against the heterologous strains, similar to those induced against the respective homologous vaccine strains. These data, therefore, fully support the use of TBE vaccines in geographic regions where virus subtypes heterologous to the vaccine strains are prevalent.
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Affiliation(s)
- Richard Fritz
- Baxter BioScience, Vaccine Research and Development, Biomedical Research Centre, Uferstrasse 15, A-2304 Orth a.d. Donau, Austria
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