The early safety profile of simultaneous vaccination against influenza and Respiratory Syncytial Virus (RSV) in patients with high-risk heart failure.

The safety of simultaneous vaccination for Respiratory Syncytial Virus (RSV) and influenza in vulnerable high-risk heart failure (HF) patients remains unclear. In an open-label, prospective study, 105 patients received concurrent influenza (Vaxigrip Tetra, season 2023/2024, Sanofi) and RSV (Arexvy, GSK) vaccinations from September 15th to November 17th, 2023. Adverse events were collected on the fourth-day post-vaccination. Overall, the vaccination was well tolerated, with the most common reaction being injection site pain (63 %). General symptoms occurred in 33 % of patients, predominantly fatigue (23 %), myalgia (12 %), and headache (9 %). Grade 3 reactions were observed in 6 % of patients, and a few experienced temperature elevation or flu-like symptoms, managing them with antipyretics. Notably, there were no exacerbations of HF, hospitalizations, or deaths within a week post-vaccination. This study indicates the safety of simultaneous influenza and RSV vaccination in high-risk HF patients, with a low incidence of mild adverse events.