Abstract
In Denmark, the 2012/13 influenza season has been dominated by influenza A(H3N2). We estimated the vaccine effectiveness (VE) of the trivalent influenza vaccine by linking national registers in a test-negative case-control study of patients tested for influenza aged ≥65 years. The adjusted VE against laboratory-confirmed influenza A and B was -11% (95% CI: -41 to 14) and 69% (95% CI: 26 to 87), respectively. Genetic characterisation of the influenza A(H3N2) viruses indicated genetic drift, with seven substitutions at key antigenic sites.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Aged
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Aged, 80 and over
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Case-Control Studies
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Denmark / epidemiology
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Female
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Hemagglutination Inhibition Tests
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Humans
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Influenza A Virus, H3N2 Subtype / genetics*
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Influenza A Virus, H3N2 Subtype / immunology
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Influenza A Virus, H3N2 Subtype / isolation & purification*
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Influenza Vaccines / administration & dosage
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Influenza Vaccines / immunology*
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Influenza, Human / diagnosis
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Influenza, Human / epidemiology
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Influenza, Human / virology*
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Male
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Outcome Assessment, Health Care*
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Population Surveillance
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RNA, Viral / genetics
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Real-Time Polymerase Chain Reaction
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Reverse Transcriptase Polymerase Chain Reaction
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Sequence Analysis, DNA
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Sex Distribution
Substances
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Influenza Vaccines
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RNA, Viral