Challenges in confirming a varicella outbreak in the two-dose vaccine era.
Vaccine
; 30(48): 6935-9, 2012 Nov 06.
Article
em En
| MEDLINE
| ID: mdl-22884663
ABSTRACT
BACKGROUND:
A second dose of varicella vaccine was recommended for U.S. children in 2006. We investigated a suspected varicella outbreak in School District X, Texas to determine 2-dose varicella vaccine effectiveness (VE).METHODS:
A varicella case was defined as an illness with maculopapulovesicular rash without other explanation with onset during April 1-June 10, 2011, in a School District X student. We conducted a retrospective cohort in the two schools with the majority of cases. Lesion, saliva, and environmental specimens were collected for varicella-zoster virus (VZV) PCR testing. VE was calculated using historic attack rates among unvaccinated.RESULTS:
In School District X, 82 varicella cases were reported, including 60 from Schools A and B. All cases were mild, with a median of 14 lesions. All 10 clinical specimens and 58 environmental samples tested negative for VZV. Two-dose varicella vaccination coverage was 66.4% in Schools A and B. Varicella VE in affected classrooms was 80.9% (95% CI 67.2-88.9) among 1-dose vaccinees and 94.7% (95% CI 89.2-97.4) among 2-dose vaccinees in School A, with a second dose incremental VE of 72.1% (95% CI 39.0-87.3). Varicella VE among School B students did not differ significantly by dose (80.1% vs. 84.2% among 1-dose and 2-dose vaccinees, respectively).CONCLUSION:
Laboratory testing could not confirm varicella as the etiology of this outbreak; clinical and epidemiologic data suggests varicella as the likely cause. Better diagnostics are needed for diagnosis of varicella in vaccinated individuals so that appropriate outbreak control measures can be implemented.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Varicela
/
Surtos de Doenças
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Vacina contra Varicela
Tipo de estudo:
Diagnostic_studies
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Observational_studies
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Risk_factors_studies
Limite:
Adolescent
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Child
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Child, preschool
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Female
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Humans
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Male
País/Região como assunto:
America do norte
Idioma:
En
Revista:
Vaccine
Ano de publicação:
2012
Tipo de documento:
Article
País de afiliação:
Estados Unidos