Acceptance and Impact of Nirsevimab and the RSVpreF Vaccine Following Implementation in Austria

Michaela Höck¹Wegene Borena²Juergen Brunner³Karina Wechselberger¹Johanna Scheiring¹Elisabeth Ralser¹Ulrike Pupp Peglow¹Peter Wöckinger¹Elisabeth D´Costa⁴Verena Kaiser³Klaus Kapelari³Gisa Gerold²Thomas Müller³Ursula Kiechl-Kohlendorfer¹Elke Griesmaier^5*

• ¹Department of Pediatrics II, Innsbruck Medical University, Innsbruck, Austria
• ²Medizinische Universitat Innsbruck Institut fur Hygiene und Medizinische Mikrobiologie, Innsbruck, Austria
• ³Department of Pediatrics I, Innsbruck Medical University, Innsbruck, Austria
• ⁴Department of Gynecology and Obstetrics, Innsbruck Medical University, Innsbruck, Austria
• ⁵Innsbruck Medical University, Innsbruck, Austria

Background Since summer 2024, passive immunization with nirsevimab (Beyfortus®) has been recommended for all infants in Austria to prevent severe respiratory syncytial virus (RSV) infection. Maternal vaccination with RSVpreF (Abrysvo®), offering transplacental protection became available in autumn 2023. The expected public health benefits of these preventive strategies depend largely on widespread acceptance; however, real-world data from Austria are currently lacking. Objective To assess the acceptance and impact of RSV immunization strategies during the 2024/2025 season in Tyrol, Austria. Methods A retrospective study was conducted including all live births at three Tyrolean maternity wards (Innsbruck, Hall, Schwaz) from December 5, 2024, to April 15, 2025. Immunization rates were analyzed, and RSV-related hospitalization frequency and duration were compared to pre-pandemic seasons. Results Of 1,156 newborns, 57% received nirsevimab and 12% had maternal RSVpreF protection, resulting in almost 70% overall coverage. RSV-related hospitalizations for children under one year of age significantly decreased from 151 in pre-pandemic seasons to 47 in the post-nirsevimab season (p = 0.018). The median age at hospital admission was significantly higher (p < 0.001), and length of stay shorter (p = 0.031) during the post-nirsevimab season. Importantly, none of the hospitalized infants had received nirsevimab, and only one was born to a vaccinated mother. Conclusion Our findings highlight the positive impact of both RSV immunization strategies – nirsevimab and RSVpreF vaccine – while underscoring the need to enhance public awareness and education to improve immunization rates. Strengthening future immunization campaigns will be key to achieving broader protection for the pediatric population and further reducing RSV-associated morbidity in early life.