After adjusting for bias in meta-analysis seasonal influenza vaccine remains effective in community-dwelling elderly. Darvishian, M.; Gefenaite, G.; Turner, R., M.; Pechlivanoglou, P.; Van Der Hoek, W.; Van Den Heuvel, E., R.; and Hak, E. Journal of Clinical Epidemiology, 67(7):734-744, Elsevier Inc, 2014.
After adjusting for bias in meta-analysis seasonal influenza vaccine remains effective in community-dwelling elderly [pdf]Paper  abstract   bibtex   
Objective To compare the performance of the bias-adjusted meta-analysis to the conventional meta-analysis assessing seasonal influenza vaccine effectiveness among community-dwelling elderly aged 60 years and older. Study Design and Setting Systematic literature search revealed 14 cohort studies that met inclusion and exclusion criteria. Laboratory-confirmed influenza, influenza-like illness, hospitalization from influenza and/or pneumonia, and all-cause mortality were study outcomes. Potential biases were identified using bias checklists. The magnitude and uncertainty of biases were assessed by expert opinion. Pooled odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated using random effects model. Results After incorporating biases, overall effect estimates regressed slightly toward no effect, with the largest relative difference between conventional and bias-adjusted ORs for laboratory-confirmed influenza (OR, 0.18; 95% CI: 0.01, 3.00 vs. OR, 0.23; 95% CI: 0.03, 2.04). In most of the studies, CIs widened reflecting uncertainties about the biases. The between-study heterogeneity reduced considerably with the largest reduction for all-cause mortality (I2 = 4%, P = 0.39 vs. I2 = 91%, P < 0.01). Conclusion This case study showed that after addressing potential biases influenza vaccine was still estimated effective in preventing hospitalization from influenza and/or pneumonia and all-cause mortality. Increasing the number of assessors and incorporating empirical evidence might improve the new bias-adjustment method. © 2014 The Authors. Published by Elsevier Inc. All rights reserved.
@article{
 title = {After adjusting for bias in meta-analysis seasonal influenza vaccine remains effective in community-dwelling elderly},
 type = {article},
 year = {2014},
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 keywords = {Vaccine effectiveness},
 pages = {734-744},
 volume = {67},
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 publisher = {Elsevier Inc},
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 abstract = {Objective To compare the performance of the bias-adjusted meta-analysis to the conventional meta-analysis assessing seasonal influenza vaccine effectiveness among community-dwelling elderly aged 60 years and older. Study Design and Setting Systematic literature search revealed 14 cohort studies that met inclusion and exclusion criteria. Laboratory-confirmed influenza, influenza-like illness, hospitalization from influenza and/or pneumonia, and all-cause mortality were study outcomes. Potential biases were identified using bias checklists. The magnitude and uncertainty of biases were assessed by expert opinion. Pooled odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated using random effects model. Results After incorporating biases, overall effect estimates regressed slightly toward no effect, with the largest relative difference between conventional and bias-adjusted ORs for laboratory-confirmed influenza (OR, 0.18; 95% CI: 0.01, 3.00 vs. OR, 0.23; 95% CI: 0.03, 2.04). In most of the studies, CIs widened reflecting uncertainties about the biases. The between-study heterogeneity reduced considerably with the largest reduction for all-cause mortality (I2 = 4%, P = 0.39 vs. I2 = 91%, P < 0.01). Conclusion This case study showed that after addressing potential biases influenza vaccine was still estimated effective in preventing hospitalization from influenza and/or pneumonia and all-cause mortality. Increasing the number of assessors and incorporating empirical evidence might improve the new bias-adjustment method. © 2014 The Authors. Published by Elsevier Inc. All rights reserved.},
 bibtype = {article},
 author = {Darvishian, Maryam and Gefenaite, Giedre and Turner, Rebecca M. and Pechlivanoglou, Petros and Van Der Hoek, Wim and Van Den Heuvel, Edwin R. and Hak, Eelko},
 journal = {Journal of Clinical Epidemiology},
 number = {7}
}
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