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Published on: December 10, 2013
Real-world effectiveness of nirsevimab against respiratory syncytial virus disease in infants: a systematic review
Dewan Md Sumsuzzman1, Zhen Wang2, Joanne M Langley3
1Agent-Based Modelling Laboratory, York University, Toronto, ON, Canada.
Insights
Nirsevimab significantly reduced hospitalizations and respiratory infections in infants. This real-world evidence confirms its effectiveness in preventing respiratory syncytial virus (RSV) disease and lowering healthcare demands.
Area of Science:
- Immunology
- Public Health
- Pediatrics
Background:
- Nirsevimab, approved in 2023, is used in infant immunization programs to prevent respiratory syncytial virus (RSV) lower respiratory tract infections (LRTI).
- Real-world data is crucial to confirm clinical trial benefits and inform immunization policies.
- This study evaluates the effectiveness of nirsevimab in real-world infant immunization programs.
Purpose of the Study:
- To assess the real-world effectiveness of nirsevimab in preventing RSV-related outcomes in infants.
- To validate clinical trial findings through a systematic review and meta-analysis of observational studies.
- To guide future immunization strategies for RSV prevention in infants.
Main Methods:
- A systematic review and meta-analysis of observational studies published between January 2023 and February 2025.
- Searched multiple databases including MEDLINE, Embase, Web of Science, Scopus, Global Health, and medRxiv.
- Pooled analyses used random-effects models to assess RSV-related hospital admissions, ICU admissions, LRTI incidence, and length of hospital stay.
Main Results:
- Nirsevimab use was associated with significantly lower odds of RSV-related hospitalization (OR 0.17) and ICU admission (OR 0.19) in infants aged 0-12 months.
- A reduction in RSV-related lower respiratory tract infection (LRTI) incidence was observed (OR 0.25).
- No significant difference in the length of hospital stay was found between nirsevimab and control groups.
Conclusions:
- The real-world effectiveness of nirsevimab mirrors its clinical trial benefits, demonstrating significant reductions in RSV disease burden.
- Nirsevimab effectively decreases RSV-related hospitalizations and infections in infants.
- These findings support the use of nirsevimab in infant immunization programs to reduce healthcare utilization for RSV.
Background:
Nirsevimab was approved in 2023, and implemented in all-infant immunisation programmes in several high-income countries to prevent lower respiratory tract infection (LRTI) caused by respiratory syncytial virus (RSV). Knowledge of real-world effectiveness of broad nirsevimab programmes is crucial to validate the benefits observed in clinical trials and guide immunisation policy. We assessed the real-world effectiveness of nirsevimab in populations where infant immunisation programmes were introduced.
Methods:
For this systematic review and meta-analysis, we searched MEDLINE, Embase, Web of Science, Scopus, Global Health, and medRxiv from Jan 1, 2023, to Feb 25, 2025, to identify observational studies of immunisation programmes for infants aged 2 years or younger in routine clinical practice reporting original data for the real-world effectiveness of nirsevimab. The primary analysis focused on infants aged 12 months or younger. Pooled analyses were done with inverse-variance random-effects models for RSV-related hospital admissions, intensive care unit (ICU) admissions, and RSV-related LRTI incidence. For length of hospital stay, we used a restricted maximum likelihood random-effects model to estimate the weighted mean difference (WMD) in days between the nirsevimab and control groups. This study is registered with PROSPERO (CRD42024628782).
Findings:
We identified and screened 1238 records, of which 32 cohort and case-control studies from five countries (France, Italy, Luxembourg, Spain, and the USA) were included in the systematic review and 27 of them were included in the meta-analysis. Nirsevimab was associated with a lower odds of RSV-related hospitalisation (odds ratio 0·17; 95% CI 0·12-0·23; I2=85·8%), a lower odds of ICU admission (0·19; 0·12-0·29; 55·6%), and a lower odds of LRTI incidence (0·25; 0·19-0·33; 35·1%) in infants aged 0-12 months. However, length of hospital stay did not differ between the nirsevimab and control groups (WMD 0·01; 95% CI -0·63 to 0·65; I2=62·3%).
Interpretation:
Our findings indicate that the benefits of nirsevimab observed in clinical trials are also evident in real-world settings, effectively reducing the burden of RSV disease in infants and, consequently, health-care use.
Funding:
Natural Sciences and Engineering Research Council of Canada and the Canadian Immunization Research Network.
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