Vaccine effectiveness of 2011/12 trivalent seasonal influenza vaccine in preventing laboratory-confirmed influenza in primary care in the United Kingdom: evidence of waning intra-seasonal protection.
Euro Surveill
; 18(5)2013 Jan 31.
Article
em En
| MEDLINE
| ID: mdl-23399424
ABSTRACT
The 2011/12 season was characterised by unusually late influenza A (H3N2) activity in the United Kingdom (UK). We measured vaccine effectiveness (VE) of the 2011/12 trivalent seasonal influenza vaccine (TIV) in a test-negative casecontrol study in primary care. Overall VE against confirmed influenza A (H3N2) infection, adjusted for age, surveillance scheme and month, was 23% (95% confidence interval (CI) -10 to 47). Stratified analysis by time period gave an adjusted VE of 43% (95% CI -34 to 75) for October 2011 to January 2012 and 17% (95% CI -24 to 45) for February 2012 to April 2012. Stratified analysis by time since vaccination gave an adjusted VE of 53% (95% CI 0 to 78) for those vaccinated less than three months, and 12% (95% CI -31 to 41) for those vaccinated three months or more before onset of symptoms (test for trend p=0.02). For confirmed influenza B infection, adjusted VE was 92% (95% CI 38 to 99). A proportion (20.6%) of UK influenza A(H3N2) viruses circulating in 2011/12 showed reduced reactivity (fourfold difference in haemagglutination inhibition assays) to the A/Perth/16/2009 2011/12 vaccine component, with no significant change in proportion over the season. Overall TIV protection against influenza A(H3N2) infection was low, with significant intraseasonal waning.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Vacinas contra Influenza
/
Influenza Humana
Tipo de estudo:
Diagnostic_studies
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Observational_studies
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Risk_factors_studies
Limite:
Adolescent
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Adult
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Aged
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Child
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Female
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Humans
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Male
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Middle aged
País/Região como assunto:
Europa
Idioma:
En
Revista:
Euro Surveill
Assunto da revista:
DOENCAS TRANSMISSIVEIS
Ano de publicação:
2013
Tipo de documento:
Article
País de afiliação:
Reino Unido