tetano
Editor, Senior Moderator
Clin Microbiol Infect
. 2026 Apr 11:S1198-743X(26)00186-2.
doi: 10.1016/j.cmi.2026.04.003. Online ahead of print.
Genomic Surveillance of Respiratory Syncytial Virus (RSV) during 2023/2024 Nirsevimab prophylaxis, Eastern Spain, early results
Beatriz Mengual-Chuliá[SUP] 1 [/SUP], Cristian Launes[SUP] 2 [/SUP], Elena Cazorla[SUP] 3 [/SUP], Mónica López-Lacort[SUP] 4 [/SUP], Cintia Muñoz-Quiles[SUP] 4 [/SUP], Ainara Mira-Iglesias[SUP] 4 [/SUP], Marta Agüera[SUP] 5 [/SUP], Daniel Penela-Sánchez[SUP] 6 [/SUP], María Garcés-Sánchez[SUP] 7 [/SUP], Carlos Fernández-García[SUP] 8 [/SUP], Héctor Cervera[SUP] 3 [/SUP], Mario Carballido-Fernández[SUP] 9 [/SUP], Ana Pineda-Caplliure[SUP] 10 [/SUP], Juan Mollar-Maseres[SUP] 11 [/SUP], Maruan Shalabi-Benavent[SUP] 12 [/SUP], Francisco Sanz-Herrero[SUP] 13 [/SUP], Javier Díez-Domingo[SUP] 14 [/SUP], Carmen Muñoz-Almagro[SUP] 15 [/SUP], Alejandro Orrico-Sánchez[SUP] 14 [/SUP], F Xavier López-Labrador[SUP] 16 [/SUP]; MEDIPRIM and VAHNSI networks; MEDIPRIM network and collaborators; VAHNSI network and collaborators
Collaborators, Affiliations
Objectives: Nirsevimab is a recombinant monoclonal antibody used to prevent lower respiratory tract infections caused by respiratory syncytial virus (RSV) in infants under one year of age. In Spain a universal immunization program for all children under one year is in place since October 2023. Our goal was to detect potential changes in the viral F protein related to nirsevimab prophylaxis.
Methods: We conducted whole-genome sequencing of 68 RSV isolates from both outpatient (n=24) and inpatient (n=59) infants under one year of age, immunized (n=42) or not (n=41) with nirsevimab, during the 2023/2024 season in Eastern Spain.
Results: The distribution of RSV clades and amino acid substitutions at nirsevimab binding sites on the F protein was (nirsevimab recipients vs. non-recipients): A.D.1 (35.71% [n=15] vs. 41.46% [n=17]); A.D.3 (9.52% [n=4] vs. 19.51% [n=8]); A.D.5 (16.66% [n=7] vs. 7.32% [n=3]); and B.D.E.1 (9.52% [n=4] vs. 24.39% [n=10]). Primary care versus inpatient distributions were A.D.1 (29.17% [n=7] vs. 42.40% [n=25]), A.D.3 (0% [n=0] vs. 20.34% [n=12]), A.D.5 (4.17% [n=1] vs. 15.25% [n=9]), and B.D.E.1 (8.33% [n=2] vs. 20.34% [n=12]). Small numbers precluded meaningful statistical comparisons. Only two clade A.D.3 isolates out of 68 RSV-A viruses showed mutations/substitutions at nirsevimab binding sites on the F protein, one of them from a nirsevimab recipient. For RSV-B, all isolates were clade B.D.E.1 carrying three substitutions at nirsevimab binding sites (I206M+Q209+S211N), regardless of nirsevimab immunization status or care setting.
Conclusions: Our study presents data from Spain, showing that the selection of nirsevimab resistance mutations has not emerged as a significant concern during the first passive immunization season, in line with other reports from France, the USA and Australia. Genome characterization of RSV will be useful for monitoring immune prophylaxis campaigns, and the emergence of potential resistance in the future.
Keywords: ILI; LRTI; Monoclonal antibody; NGS; SARI; bronchiolitis; immune escape; mutation.
. 2026 Apr 11:S1198-743X(26)00186-2.
doi: 10.1016/j.cmi.2026.04.003. Online ahead of print.
Genomic Surveillance of Respiratory Syncytial Virus (RSV) during 2023/2024 Nirsevimab prophylaxis, Eastern Spain, early results
Beatriz Mengual-Chuliá[SUP] 1 [/SUP], Cristian Launes[SUP] 2 [/SUP], Elena Cazorla[SUP] 3 [/SUP], Mónica López-Lacort[SUP] 4 [/SUP], Cintia Muñoz-Quiles[SUP] 4 [/SUP], Ainara Mira-Iglesias[SUP] 4 [/SUP], Marta Agüera[SUP] 5 [/SUP], Daniel Penela-Sánchez[SUP] 6 [/SUP], María Garcés-Sánchez[SUP] 7 [/SUP], Carlos Fernández-García[SUP] 8 [/SUP], Héctor Cervera[SUP] 3 [/SUP], Mario Carballido-Fernández[SUP] 9 [/SUP], Ana Pineda-Caplliure[SUP] 10 [/SUP], Juan Mollar-Maseres[SUP] 11 [/SUP], Maruan Shalabi-Benavent[SUP] 12 [/SUP], Francisco Sanz-Herrero[SUP] 13 [/SUP], Javier Díez-Domingo[SUP] 14 [/SUP], Carmen Muñoz-Almagro[SUP] 15 [/SUP], Alejandro Orrico-Sánchez[SUP] 14 [/SUP], F Xavier López-Labrador[SUP] 16 [/SUP]; MEDIPRIM and VAHNSI networks; MEDIPRIM network and collaborators; VAHNSI network and collaborators
Collaborators, Affiliations
- PMID: 41974354
- DOI: 10.1016/j.cmi.2026.04.003
Objectives: Nirsevimab is a recombinant monoclonal antibody used to prevent lower respiratory tract infections caused by respiratory syncytial virus (RSV) in infants under one year of age. In Spain a universal immunization program for all children under one year is in place since October 2023. Our goal was to detect potential changes in the viral F protein related to nirsevimab prophylaxis.
Methods: We conducted whole-genome sequencing of 68 RSV isolates from both outpatient (n=24) and inpatient (n=59) infants under one year of age, immunized (n=42) or not (n=41) with nirsevimab, during the 2023/2024 season in Eastern Spain.
Results: The distribution of RSV clades and amino acid substitutions at nirsevimab binding sites on the F protein was (nirsevimab recipients vs. non-recipients): A.D.1 (35.71% [n=15] vs. 41.46% [n=17]); A.D.3 (9.52% [n=4] vs. 19.51% [n=8]); A.D.5 (16.66% [n=7] vs. 7.32% [n=3]); and B.D.E.1 (9.52% [n=4] vs. 24.39% [n=10]). Primary care versus inpatient distributions were A.D.1 (29.17% [n=7] vs. 42.40% [n=25]), A.D.3 (0% [n=0] vs. 20.34% [n=12]), A.D.5 (4.17% [n=1] vs. 15.25% [n=9]), and B.D.E.1 (8.33% [n=2] vs. 20.34% [n=12]). Small numbers precluded meaningful statistical comparisons. Only two clade A.D.3 isolates out of 68 RSV-A viruses showed mutations/substitutions at nirsevimab binding sites on the F protein, one of them from a nirsevimab recipient. For RSV-B, all isolates were clade B.D.E.1 carrying three substitutions at nirsevimab binding sites (I206M+Q209+S211N), regardless of nirsevimab immunization status or care setting.
Conclusions: Our study presents data from Spain, showing that the selection of nirsevimab resistance mutations has not emerged as a significant concern during the first passive immunization season, in line with other reports from France, the USA and Australia. Genome characterization of RSV will be useful for monitoring immune prophylaxis campaigns, and the emergence of potential resistance in the future.
Keywords: ILI; LRTI; Monoclonal antibody; NGS; SARI; bronchiolitis; immune escape; mutation.