Effect of vaccines and antivirals during the major 2009 A(H1N1) pandemic wave in Norway--and the influence of vaccination timing.
PLoS One
; 7(1): e30018, 2012.
Article
em En
| MEDLINE
| ID: mdl-22253862
ABSTRACT
To evaluate the impact of mass vaccination with adjuvanted vaccines (eventually 40% population coverage) and antivirals during the 2009 influenza pandemic in Norway, we fitted an age-structured SEIR model using data on vaccinations and sales of antivirals in 2009/10 in Norway to Norwegian ILI surveillance data from 5 October 2009 to 4 January 2010. We estimate a clinical attack rate of approximately 30% (28.7-29.8%), with highest disease rates among children 0-14 years (43-44%). Vaccination started in week 43 and came too late to have a strong influence on the pandemic in Norway. Our results indicate that the countermeasures prevented approximately 11-12% of potential cases relative to an unmitigated pandemic. Vaccination was found responsible for roughly 3 in 4 of the avoided infections. An estimated 50% reduction in the clinical attack rate would have resulted from vaccination alone, had the campaign started 6 weeks earlier. Had vaccination been prioritized for children first, the intervention should have commenced approximately 5 weeks earlier in order to achieve the same 50% reduction. In comparison, we estimate that a non-adjuvanted vaccination program should have started 8 weeks earlier to lower the clinical attack rate by 50%. In conclusion, vaccination timing was a critical factor in relation to the spread of the 2009 A(H1N1) influenza. Our results also corroborate the central role of children for the transmission of A(H1N1) pandemic influenza.
Texto completo:
1
Coleções:
01-internacional
Contexto em Saúde:
1_ASSA2030
/
2_ODS3
Base de dados:
MEDLINE
Assunto principal:
Antivirais
/
Vacinas contra Influenza
/
Vacinação
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Vírus da Influenza A Subtipo H1N1
/
Pandemias
Tipo de estudo:
Diagnostic_studies
/
Prevalence_studies
/
Risk_factors_studies
Limite:
Adolescent
/
Adult
/
Aged
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Child
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Child, preschool
/
Humans
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Infant
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Middle aged
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Newborn
País/Região como assunto:
Europa
Idioma:
En
Revista:
PLoS One
Ano de publicação:
2012
Tipo de documento:
Article