title: Author's reply: Regarding the editorial by Penttinen and Friede.
authors.affiliation: European Centre for Disease Prevention and Control (ECDC), Stockholm, Sweden.
authors.forename: Pasi M
authors.initials: PM
authors.lastname: Penttinen
authors.forename: Martin H
authors.initials: MH
authors.lastname: Friede
mesh_terms: D006801:Humans; D007252:Influenza Vaccines; D007251:Influenza, Human
chemical_list: D007252:Influenza Vaccines
keywords: Keywords: influenza; vaccine effectiveness; vaccines and immunisation