Estimating influenza-related hospitalization in The Netherlands.

The purpose of this study was to examine the impact of influenza on hospitalization in The Netherlands. Two methods were applied to estimate this effect: (a) regression analysis and (b) comparison of hospitalization in epidemic years with non-epidemic years. Hospital discharge rates in 1984-93 have been considered. The study shows that, during the period studied, on average, almost 2700 people were hospitalized for influenza per annum, and that influenza was diagnosed as the main cause for hospitalization in only a fraction of these hospitalizations (326: 12%). From an economic perspective, these results imply that the cost-effectiveness of vaccination against influenza may be severely underestimated when looking only at changes achieved in the number of hospitalizations attributed to influenza.