Work

Changes in RSV-associated lower respiratory tract infections among hospitalized and outpatient children under 2 years in Northern Bavaria after general recommendation of Nirsevimab immunization in 2024

Year: 2025

Type: article

Abstract: PURPOSE: This study investigated changes in the incidence and age distribution of RSV-associated lower respiratory tract infections (RSV-LRTI) among children in Northern Bavaria after the general recommendation of Nirsevimab immunization in 2024. METHODS: Postnatal Nirsevimab immunization coverage was assessed at the University Hospital Würzburg (UKW) in children born between 11/2024 and 03/2025. Age distribution of in- and outpatients < 2 years with PCR-confirmed RSV-LRTI was assessed from UKW (ICD-10 based) and pediatric practices in Würzburg for November-March in 2022/23 (S1), 2023/24 (S2) and 2024/25 (S3). Age distribution of RSV cases from nationwide mandatory laboratory RSV surveillance (Robert Koch-Institute) was analyzed for November-March in 2023/24 and 2024/25. RESULTS: Between 11/2024 and 03/2025, postnatal Nirsevimab immunization coverage for newborns at the UKW was 68% (566/833). In the RSV seasons S1/S2/S3, 98/84/29 children < 2 years with RSV-LRTI were hospitalized. The proportion of children < 1 year decreased from 78%/80% in S1/S2 to 42% in S3 (S1 vs. S3 p < 0.001, S2 vs. S3 p < 0.001). In 36/68/30 outpatients < 2 years with RSV-LRTI, the proportion of children < 1 year decreased from 44%/60% in S1/S2 to 33% in S3 (S1 vs. S3 p = 0.358; S2 vs. S3 p = 0.014). In nationwide laboratory RSV surveillance, 23,171/12,826 children < 2 years were reported in S2/S3, with a decrease in the proportion of children < 1 year from 65% in S2 to 47% in S3 (p < 0.001). CONCLUSIONS: We observed a clear decrease of RSV-LRTI in hospitalized and outpatient infants < 1 year of age in the first RSV season, suggesting a relevant impact following Nirsevimab recommendation in Germany.

Source: Infection

DOI: 10.1007/s15010-025-02654-1