European RSV immunization linked to drop in infant hospitalizations
Infant RSV Hospitalizations Drop Following Immunization Rollouts Across Europe
National immunization programs utilizing nirsevimab or maternal vaccination against respiratory syncytial virus (RSV) are associated with large reductions in infant hospitalizations across Europe, though countries have implemented these measures with wide variation, particularly for preterm infants. Two European studies presented on October 29 at the Congress of the European Paediatric Academic Societies (CEPAS) 2026 detailed these findings.
The research evaluated real-world public health impacts across Spain, the Netherlands, and the United Kingdom by examining routine hospital administrative data for infants aged 24 months or younger hospitalized with lower respiratory tract infections or RSV-related lower respiratory tract infections. Jeroen Geurtsen, MSc, of Global Medical Vaccines at Sanofi B.V. in Amsterdam, pointed out that although long-acting monoclonal antibodies such as nirsevimab have been available since 2022, European countries have implemented them in different ways.
Key Clinical Takeaways:
- Spain introduced universal nirsevimab immunization for all infants in autumn 2023, achieving a 66.9% average reduction in RSV-related lower respiratory tract infection hospitalizations among infants aged 0-12 months.
- The UK implemented year-round maternal RSV vaccination in September 2024, adding nirsevimab for high-risk infants and those born before 32 weeks’ gestation by September 2025, which linked to a 32.5% reduction in hospitalizations for infants aged 0-12 months.
- The Netherlands introduced universal nirsevimab coverage in autumn 2025 following out-of-pocket maternal vaccination options, showing a 46.4% decrease in RSV-related lower respiratory tract infection hospitalizations over a single post-implementation season.
Real-World Effectiveness Across Three European Nations
To examine real-world public health impact, researchers analyzed four consecutive RSV seasons between June 2022 and May 2026. Just under half of all hospital admissions occurred in infants aged zero to six months, with a further one-quarter occurring in those aged seven to 12 months. The mean age at admission ranged from seven to nine months, and roughly three-fifths of the hospitalized infants were male.
In Spain, the 66.9% average reduction in RSV-related lower respiratory tract infection hospitalizations among infants aged 0-12 months across three post-implementation seasons rose to 75.7% in infants aged 0-6 months, compared with 36.8% in those aged 7-12 months. In the UK, the 32.5% average reduction across two post-implementation seasons included a 39.8% decrease in infants aged 0-6 months versus 5.1% in those aged 7-12 months. In the Netherlands, the 46.4% decrease over a single post-implementation season included a 56.1% drop in infants aged 0-6 months compared with 26.5% in those aged 7-12 months.
According to information gathered from intensive care units in Spain and the UK, ICU admissions for babies aged 0-12 months dropped by 74.5% and 49.7% respectively, whereas the typical duration of an ICU stay remained largely unchanged.
Immunization Strategy Disparities for Preterm Infants
In a separate presentation, Sara Marie Nilsen, PhD, of the Department of Clinical and Molecular Medicine at the Norwegian University of Science and Technology in Trondheim, Norway, outlined a mapping of immunization strategies against RSV and influenza in children born preterm. Nilsen noted that preterm-born children face a 10-fold increased risk of respiratory tract infections requiring hospitalization if born before 28 weeks’ gestation, and that this heightened risk extends beyond infancy into early childhood.
When researchers evaluated vaccination frameworks across the 11 nations involved in the EU-backed IMPROVE PRETERM initiative—namely Denmark, Estonia, Finland, France, Germany, Norway, Poland, Portugal, Sweden, Switzerland, and the UK—they uncovered significant divergence heading into the 2025-2026 season. France, Finland, Germany, Portugal, Sweden, and Switzerland offered universal RSV protection for all infants, while the remaining five countries had some form of restriction based on weeks of gestation. Denmark, France, Poland, Switzerland, and the UK provided free national maternal vaccination programs, whereas the other six countries did not.
For a child’s second RSV season, only Switzerland maintained a specific strategy for children born before 32 weeks’ gestation. For influenza immunization, only Norway specified gestational age as an eligibility criterion, targeting infants born before 32 weeks’ gestation. Session co-chair Jasna Petrić Duvnjak, MD, a pediatric pulmonologist at Poliklinika Pediatri in Split, Croatia, questioned the root causes of these national divergences.
Why are we so different? Why do we have so different schedules?
Petrić Duvnjak suggested that while cultural hesitation regarding vaccination plays a role, the primary driver is political, noting that decision-makers are not physicians or clinicians involved in caring for sick children. The REACH study was funded by Sanofi and AstraZeneca, with several authors employed by Sanofi. The IMPROVE PRETERM project received funding from the European Union’s Horizon Europe Research and Innovation program.
Disclaimer: The information provided in this article is for educational and scientific communication purposes only and does not constitute medical advice. Always consult with a qualified healthcare provider regarding any medical condition, diagnosis, or treatment plan.