Assessing different measures of population-level vaccine protection using a case-control study.
Vaccine
; 33(48): 6878-83, 2015 Nov 27.
Article
en En
| MEDLINE
| ID: mdl-26364121
ABSTRACT
BACKGROUND:
Case-control studies have not been examined for their utility in assessing population-level vaccine protection in individually randomized trials.METHODS:
We used the data of a randomized, placebo-controlled trial of a cholera vaccine to compare the results of case-control analyses with those of cohort analyses. Cases of cholera were selected from the trial population followed for three years following dosing. For each case, we selected 4 age-matched controls who had not developed cholera. For each case and control, GIS was used to calculate vaccine coverage of individuals in a surrounding "virtual" cluster. Specific selection strategies were used to evaluate the vaccine protective effects.RESULTS:
66,900 out of 108,389 individuals received two doses of the assigned regimen. For direct protection among subjects in low vaccine coverage clusters, we observed 78% (95% CI 47-91%) protection in a cohort analysis and 84% (95% CI 60-94%) in case-control analysis after adjusting for confounding factors. Using our GIS-based approach, estimated indirect protection was 52% (95% CI 10-74%) in cohort and 76% (95% CI 47-89%) in case control analysis. Estimates of total and overall effectiveness were similar for cohort and case-control analyses.CONCLUSION:
The findings show that case-control analyses of individually randomized vaccine trials may be used to evaluate direct as well as population-level vaccine protection.Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Vacunas contra el Cólera
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Ensayos Clínicos Controlados Aleatorios como Asunto
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Cólera
Tipo de estudio:
Clinical_trials
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Etiology_studies
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Incidence_studies
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Observational_studies
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Risk_factors_studies
Límite:
Adolescent
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Adult
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Aged
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Aged80
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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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Infant
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Male
Idioma:
En
Revista:
Vaccine
Año:
2015
Tipo del documento:
Article