University Hospital Inselspital, Berne Collaborator: Boehringer Ingelheim Abbott Merck Sharp & Dohme Corp. Solvay Pharmaceuticals https://ichgcp.net/clinical-trials-registry/NCT00783380 March 2008 Phase 4 Virosomal influenza vaccine Influvacplus 2005/2006, Solvay Pharma AG, Bern, Switzerland Assigned to all 4 groups if immunocompromized patients https://clinicaltrials.gov/ct2/history/NCT00783380?V_2=View