Intrahospital Influenza Vaccination in Patients at High Cardiovascular Risk (VACC-UP)

The aim of this study is to evaluate the effect of offering intrahospital influenza vaccination as an adjunct to active counseling during the index hospitalization to adult patients hospitalized for acute coronary syndrome (ACS) or congestive heart failure (CHF), compared with active counseling alone, on influenza vaccination rates in patients at high cardiovascular risk. Patients are randomized 1:1 to either an offer of bedside intrahospital influenza vaccination according to the recommendations of the German Standing Vaccination Committee (STIKO) in addition to standardized active counseling (intervention group), or standardized active counseling plus the standard-of-care recommendation for ambulatory vaccination in the discharge papers (control group). The primary endpoint is the influenza vaccination rate at the end of the index season (March 31).

Inclusion Criteria: * Age 18 years or older * Hospitalized due to acute coronary syndrome (ACS) or congestive heart failure (CHF) and fulfilling the criteria for influenza vaccination according to the recommendations of the German Standing Vaccination Committee (STIKO) * Written informed consent Exclusion Criteria: * Already received seasonal influenza vaccination in the current season, based on self-reported vaccination status and/or vaccination certificate * Laboratory-confirmed active influenza infection during the index hospitalization * Contraindication for vaccination (e.g., known allergy) * Inability to provide written informed consent