Second Study sites protocols and clearance from Ethical Committee to measure influenza vaccine effectiveness.

This will include additional information obtained through deliverables D4.1. The study sites will adapt the generic influenza protocol by describing the study design(s), the outcomes, the settings (GP, hospital based), the types of vaccines, the plan of analysis, the variables that will be included in the analysis and how these are obtained, how previous vaccinations are accounted for etc. The plan of analysis will describe how to measure vaccine effectiveness (direct effect) in the elderly population, including adjustment for confounders by covariates or (if possible) imputations.