Nirsevimab Cuts RSV Hospitalizations in Spanish Study

TOPLINE:

The introduction of universal passive immunisation with nirsevimab, a long-acting monoclonal antibody, led to significant reductions in hospitalizations and paediatric intensive care admissions for respiratory syncytial virus–associated lower respiratory tract infections (RSV-LRTIs), particularly benefiting infants younger than 6 months.

METHODOLOGY:

• Researchers carried out a prospective observational study at a tertiary hospital in Spain to examine if universally administering nirsevimab could reduce hospitalizations and paediatric intensive care admissions due to RSV-LRTIs in children younger than 5 years.
• They analysed 311 patients (median age, 4.9 months; 57.5% boys), comparing hospitalization rates during the October 2023-March 2024 RSV season — when nirsevimab was administered — with those during two pre-pandemic seasons (2018-2019 and 2019-2020) and one post-pandemic season (2022-2023).
• Nirsevimab immunoprophylaxis was given to all newborns with a gestational age of at least 35 weeks, to infants younger than 6 months, and to high-risk children younger than 2 years.

TAKEAWAY:

• RSV-LRTI hospitalizations in infants younger than 6 months declined by 83.3% (95% CI, 70.9-95.8) during the period when nirsevimab was administered compared with those in the pre-pandemic periods and declined by 90.8% (95% CI, 83.6-98.0) compared with those in the post-pandemic period.
• Additionally, paediatric intensive care admissions declined by 73.3% during the period when nirsevimab was administered compared with those in the pre-pandemic periods and by 87.9% compared with those in the post-pandemic period.
• The median age of hospitalized patients significantly increased during the nirsevimab period, rising to 15.6 months, whereas it was 4 months and 3.4 months in the pre- and post-pandemic periods, respectively (P < .001).
• Additionally, hospital stays were shorter during the nirsevimab period, with a median of 4 days, whereas they lasted a median of 6 days and 5 days in the pre- and post-pandemic periods, respectively (P = .003).

IN PRACTICE:

“These findings are encouraging, and it is anticipated that in the coming years, nirsevimab prophylaxis will mitigate the significant burden on healthcare services during the winter season,” the authors wrote.

SOURCE:

The study was led by Lorena Bermúdez-Barrezueta, Faculty of Medicine, Valladolid University, Valladolid, Spain. It was published online on May 16, 2025, in the European Journal of Pediatrics.

LIMITATIONS:

This was a single-centre study with a limited sample size.

DISCLOSURES:

The study was supported by FEDER European Funds and the Junta de Castilla y León under the Research and Innovation Strategy for Smart Specialization and partially funded by the Ernesto Sanchez Villares Foundation.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.