title: Case-control studies to assess vaccine effectiveness? Yes, but not this way.
authors.forename: Enrique
authors.initials: E
authors.lastname: Bernaola
authors.forename: Mercedes
authors.initials: M
authors.lastname: Herranz
authors.forename: Nuria
authors.initials: N
authors.lastname: Clerigue
authors.forename: Francisco
authors.initials: F
authors.lastname: Gil
mesh_terms: D016022:Case-Control Studies; D006801:Humans; D011008:Pneumococcal Infections / Q000453:epidemiology / Q000517:prevention & control*; D022242:Pneumococcal Vaccines; D012307:Risk Factors; D015983:Selection Bias
chemical_list: D022242:Pneumococcal Vaccines