Generic protocols to measure influenza vaccine effectiveness at primary care and hospital level, using a test-negative design and screening method.

The generic protocols will include a description of the study design, the setting(s), the plan of analysis for study site estimates and for pooled estimates, the minimum set of variables to be collected, the sample size. They will specify the parts that each study site will have to document when writing the study site protocol. The generic protocols will detail the methods used and the plan of analysis to answer to specific research questions such as the effect of previous vaccinations and the duration of protection).