Applying Current Methods for Estimating Influenza Burden to an Academic Health Sciences Centre

Abstract

Public health planning for influenza is based on morbidity and mortality estimates derived from statistical models. Lower than anticipated 2009 H1N1 pandemic death estimates have raised questions about the method. Examining the statistical method is important for future policy and program development. We compared the main methods of estimating influenza burden through a systematic literature review and by comparing statistical estimates of influenza-attributable burden at the Ottawa Hospital (TOH) to clinical estimates validated through chart review. We identified heterogeneity in methods used to estimate influenza-attributable mortality in the literature which resulted in within-season estimate variation by study. We found statistical estimates of influenza burden at TOH to be 4-8 times greater than clinically validated data. We also found no significant association between the outcomes examined and epidemic periods at TOH. The findings of this study suggest discordance between model estimates by model approach and between model estimates and validated findings. Examining reasons for these discordances should be pursued.