Journal Article

Respiratory syncytial virus–related lower respiratory tract infection hospitalizations in infants receiving nirsevimab in Galicia (Spain): the NIRSE-GAL study

Suárez-Gaiche, Nuria, González-Pérez, Juan-Manuel, Platero-Alonso, Leticia, Salas, Antonio, Dacosta-Urbieta, Ana, Nartallo-Penas, Victoria, Rivero-Calle, Irene, Otero-Barrós, María-Teresa, Piñeiro-Sotelo, Marta, Santiago-Pérez, María-Isolina, Martinón-Torres, Federico, Ces-Ozores, Olga-María, Pérez-Martínez, Olaia, Durán-Parrondo, Carmen, Manzanares, Angela, Jin, Jing, Alvárez-Gil, Rosa-María, Mallah, Narmeen, Kramer, Rolf, Mirás-Carballal, Susana, Pardo-Seco, Jacobo, Rodríguez-Tenreiro-Sánchez, Carmen

2025

Overview

As part of the NIRSEGAL study ( https://www.nirsegal.es/en ), we present the clinical characteristics and course of respiratory syncytial virus (RSV)-related low respiratory tract infection (LRTI) hospitalizations in infants eligible for nirsevimab administration during the 2023–2024 season. Infants eligible for nirsevimab immunization (born between 1 April, 2023, and 30 March, 2024) who were hospitalized due to RSV-related LRTI between September 25, 2023, and April 15, 2024, in a hospital from the Galician Public Health system were included. Clinical and demographic characteristics of RSV-related LRTI hospitalizations were analyzed, with comparisons made between breakthrough cases (those immunized with nirsevimab) and non-breakthrough cases. During the study period, 69 RSV-related LRTI hospitalizations were recorded, with a median hospital stay of 4 (interquartile range (IQR) 3–6) days; 65.2% ( N  = 45) were breakthrough cases. The median age was 2.7 (IQR 1.5–5.2) months, and more than half of them ( N  = 39, 56.5%) were male. The incidence of cases was parallel to the RSV epidemic curve, suggesting no waning of nirsevimab efficacy. Of the total hospitalizations, 16 infants (23.2%) had a high-risk condition, 44 (63.8%) needed oxygen support, 15 (21.7%) were admitted to the intensive care unit (ICU), and 11 (15.9%) received non-invasive mechanical ventilation (NIMV). No statistically significant differences were observed in these characteristics when comparing breakthrough and non-breakthrough cases. Conclusion : In the nirsevimab era, a substantial proportion of children who were hospitalized for RSV-related LRTI needed oxygen support, NIMV, and ICU admission. Clinical characteristics, timing, and outcomes were comparable between breakthrough and non-breakthrough cases. Trial registration : The NIRSE-GAL study protocol was registered on ClinicalTrials.gov (NCT06180993). What is Known : • Nirsevimab, a long-acting monoclonal antibody, has shown high effectiveness in preventing RSV-related hospitalizations and has been included in some European countries’ immunization programs . What is New: • During the first RSV season after the universal implementation of nirsevimab in Galicia (Spain), a large proportion of hospitalized infants had high-risk conditions, yet disease severity markers (oxygen need, ICU admission, NIVM) were comparable between breakthrough and non-breakthrough cases . • No signal of waning protection over time was observed among breakthrough cases, reinforcing the potential value of early, season-wide immunization .

• Publisher: Springer Berlin Heidelberg,Springer Nature B.V
• Subject: Antibodies, Monoclonal, Humanized - therapeutic use / Antiviral Agents - therapeutic use / Brief Report / Female / Hospitalization / Hospitalization - statistics & numerical data / Humans / Immunization / Infant / Infants / Male / Mechanical ventilation / Medicine / Medicine & Public Health / Monoclonal antibodies / Oxygen / Pediatrics / Public health / Respiratory syncytial virus / Respiratory Syncytial Virus Infections - drug therapy / Respiratory Syncytial Virus Infections - epidemiology / Respiratory Syncytial Virus Infections - therapy / Respiratory tract infection / Respiratory Tract Infections - epidemiology / Respiratory Tract Infections - therapy / Respiratory Tract Infections - virology / Spain - epidemiology / Statistical analysis