Clinical Research Directory

Inclusion Criteria: * Patients hospitalized with newly diagnosed type 1 diabetes mellitus. * Written informed consent (parents, legal guardian). Exclusion Criteria: * Influenza vaccination during the current influenza season. * Strong indication for influenza vaccination for non-diabetic disease. * Severe allergy to eggs or previous allergic reaction to influenza vaccine. * Suspicion of febrile illness or acute, ongoing infection. * Hypersensitivity to the active substances or ingredients of Vaxigrip Tetra or against any residues, such as eggs (ovalbumin or chicken proteins), neomycin, formaldehyde and octoxinol. * Patients with endogenic or iatrogenic immunosuppression that may result in reduced immunization response. * Inability to provide informed consent from a parent or legal guardian. * Age \<7 or ≥18 years. * Previous randomization in the INVITED trial.