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Observational Study
. 2024 Dec;18(12):e70054.
doi: 10.1111/irv.70054.

Changes in Respiratory Syncytial Virus-Associated Hospitalisations Epidemiology After Nirsevimab Introduction in Lyon, France

Cécile Chauvel  1   2 , Côme Horvat  3 , Etienne Javouhey  3   4 , Yves Gillet  3   5 , Juliette Hassenboehler  1   2 , Claire Nour Abou Chakra  1   2 , Corinne Ragouilliaux  6 , Franck Plaisant  7 , Dominique Ploin  3   8 , Marine Butin  5   9 , Jean-Sebastien Casalegno  8   10 , Marta C Nunes  1   2   11
Affiliations
Observational Study

Changes in Respiratory Syncytial Virus-Associated Hospitalisations Epidemiology After Nirsevimab Introduction in Lyon, France

Cécile Chauvel et al. Influenza Other Respir Viruses. 2024 Dec.

Abstract

Background: Respiratory Syncytial Virus (RSV) is a major health concern, particularly for infants. In France, Nirsevimab, a long-acting monoclonal antibody to prevent RSV-associated lower respiratory tract infections (LRTI) was available from September 2023. We described RSV-associated LRTI hospitalisations during the 2023-2024 season among infants younger than six months born at the Hospices Civils de Lyon (HCL), and evaluated the effectiveness of Nirsevimab against RSV-LRTI hospitalisation.

Methods: This observational study included infants born and hospitalised at the HCL during the 2023-2024 season, along with pre-COVID-19 and 2022-2023 seasons. Information on Nirsevimab immunisation status, clinical and perinatal variables were collected through routine care. Infants' characteristics and incidence rate of hospitalisation per 100 births during 2023-2024 were compared with the historical periods overall and by delay between birth and the onset of the RSV season. Nirsevimab effectiveness was computed by the screening method.

Results: During the 2023-2024 season, 83 infants younger than six months were hospitalised with an RSV-associated LRTI. Compared with the historical periods (640 pre-COVID-19 and 123 in 2022-2023), these infants were older. Incidence rate for infants born during the period when immunisation was available were lower than the previous seasons; incidence rate ratios were 0.45 (95% confidence interval [CI]: 0.33; 0.62) in 2023-2024 compared with pre-COVID-19 period and 0.53 (95%CI: 0.36; 0.77) compared with 2022-2023 season. Nirsevimab effectiveness was 78.3% (95%CI: 55.9; 89.5) with a coverage of 79.3% in the two main HCL maternities.

Conclusions: High Nirsevimab coverage and effectiveness were estimated in a real-world setting. A change in the age distribution of RSV-associated LRTI hospitalisations in 2023-2024 was noted compared with historical seasons.

Keywords: Beyfortus; LRTI; Nirsevimab; RSV; effectiveness; monoclonal antibody; paediatrics; real‐world evidence.

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Conflict of interest statement

MCN reports grants from Sanofi; and personal fees from Pfizer and Sanofi. EJ reports personal fees from Sanofi. None declared for the other authors.

Figures

FIGURE 1
FIGURE 1
Epidemic curves of RSV‐associated lower respiratory tract infection hospitalisations among infants younger than six months born at the Hospices Civils de Lyon. Shaded area represents the RSV‐associated hospitalisations during the 2023–2024 season.RSV‐associated lower respiratory tract infection hospitalisations detected in the historical season: 2015–2016:141, 2016–2017:103, 2017–2018:119, 2018–2019:140, 2019–2020:137, 2022–2023:123.
FIGURE 2
FIGURE 2
Incidence of RSV‐associated lower respiratory tract infection hospitalisations during the first six months of life among the Hospices Civils de Lyon birth cohort for pre‐COVID‐19, 2022–2023 and 2023–2024 seasons. *For 2023–2024 season, overall includes all infants born from 18 September to 31 December 2023 (−2 to 2 months). In panels B and D, the dotted vertical line corresponds to the first administration of Nirsevimab.
See this image and copyright information in PMC

References

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