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

July 18, 2026 updated by: Stephan Baldus

Intrahospital Vaccination and Active Counseling Versus Active Counseling Alone to Increase Seasonal Influenza immUnization in Patients at High Cardiovascular Risk in Germany: The Randomized Controlled VACC-UP Study

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).

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

482

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

  • Germany
      • Cologne, Germany, 50937
        • Clinic III for Internal Medicine, University Hospital of Cologne
        • Contact:
        • Principal Investigator:
          • Stephan Baldus, Prof. Dr. med.
      • Hamburg, Germany, 20246
        • Department of Cardiology, University Heart and Vascular Centre Hamburg
        • Principal Investigator:
          • Natalie Arnold, Dr. med.

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

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

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Health Services Research
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Intrahospital vaccination offer
Patients receive standardized active influenza vaccination counseling and are additionally offered bedside intrahospital vaccination against seasonal influenza according to the latest STIKO recommendations at any time prior to discharge during the index hospitalization.
Biological: Intrahospital seasonal influenza vaccination offer
Offer of bedside vaccination against seasonal influenza during the index hospitalization, administered in a standardized manner by trained treating physicians according to the latest STIKO recommendations and the respective product information. The appropriate vaccine is selected according to current recommendations (e.g., high-dose quadrivalent vaccine for patients aged 60 years and older, standard-dose quadrivalent vaccine otherwise). Vaccination is offered from September 1 to February 28 of the respective influenza season.
Other Names:
  • Seasonal influenza vaccine (high-dose or standard-dose according to STIKO recommendations)
Behavioral: Standardized active influenza vaccination counseling
Standardized active counseling on influenza vaccination using a cardiovascular gain-framed information sheet, including the recommendation to be vaccinated and the opportunity to discuss vaccination with the treating physician. Counseling is provided to all patients in both arms after completion of the baseline 7C questionnaire and prior to randomization.
Active Comparator: Active counseling alone (standard of care)
Patients receive standardized active influenza vaccination counseling and the current standard of care in Germany, i.e., the recommendation to obtain ambulatory influenza vaccination as stated in the discharge papers. No intrahospital influenza vaccination is administered during the index hospitalization.
Behavioral: Standardized active influenza vaccination counseling
Standardized active counseling on influenza vaccination using a cardiovascular gain-framed information sheet, including the recommendation to be vaccinated and the opportunity to discuss vaccination with the treating physician. Counseling is provided to all patients in both arms after completion of the baseline 7C questionnaire and prior to randomization.
Behavioral: Standard of care discharge recommendation for ambulatory vaccination
Current standard of care in Germany: the recommendation to obtain ambulatory influenza vaccination from the primary care physician, stated in the discharge papers.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Influenza vaccination rate at the end of the index influenza season
Time Frame: From randomization to the end of the index influenza season (March 31), up to approximately 7 months
Proportion of patients vaccinated against seasonal influenza at the end of the index season (defined as March 31). For intervention group patients vaccinated during the index hospitalization, vaccination status is documented from inpatient medical records. For control group patients and intervention group patients who declined intrahospital vaccination, self-reported vaccination status is assessed by telephone interview beginning April 1 and cross-validated with data from the treating general practitioner.
From randomization to the end of the index influenza season (March 31), up to approximately 7 months

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Influenza vaccination rate at the end of the post-index influenza season
Time Frame: From randomization to the end of the post-index influenza season (March 31 of the following year), up to approximately 19 months
Proportion of patients vaccinated against seasonal influenza at the end of the post-index season. For all patients, self-reported vaccination status is assessed by telephone interview beginning April 1 of the post-index season and cross-validated with data from the treating general practitioner.
From randomization to the end of the post-index influenza season (March 31 of the following year), up to approximately 19 months
Association of the individual components of the 7C psychological antecedents of vaccination questionnaire with vaccination status
Time Frame: Baseline (prior to counseling and randomization) and end of the index influenza season (March 31), up to approximately 7 months
Association of the individual components of the 7C psychological antecedents of vaccination questionnaire (7-point scale, long version), assessed at baseline prior to active counseling, with vaccination status at the end of the index season. Assessed using univariate and multivariable regression models reporting odds ratios with 95% confidence intervals.
Baseline (prior to counseling and randomization) and end of the index influenza season (March 31), up to approximately 7 months
Patient satisfaction with the offer of intrahospital influenza vaccination
Time Frame: During the index hospitalization, up to approximately 14 days
Descriptive assessment of patient satisfaction with the intrahospital vaccination offer, based on a study-specific patient satisfaction questionnaire completed by patients in the intervention group.
During the index hospitalization, up to approximately 14 days

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Stephan Baldus

Collaborators

Sanofi

Investigators

  • Principal Investigator: Stephan Baldus, Prof. Dr. med., Clinic III for Internal Medicine, University Hospital of Cologne
  • Study Director: Sebastian Heyne, Dr. med., Clinic III for Internal Medicine, University Hospital of Cologne

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

September 1, 2026

Primary Completion (Estimated)

March 1, 2028

Study Completion (Estimated)

June 1, 2029

Study Registration Dates

First Submitted

July 18, 2026

First Submitted That Met QC Criteria

July 18, 2026

First Posted (Actual)

July 23, 2026

Study Record Updates

Last Update Posted (Actual)

July 23, 2026

Last Update Submitted That Met QC Criteria

July 18, 2026

Last Verified

July 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 26-1232

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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