First preliminary data on the effectiveness of nirsevimab against RSV in Spain

Content
● Introduction (see). ● The first data on the effectiveness of nirsevimab were published in Spain (see) | Goal (see) | Methodology (see) | Results (see). ● Conclusions and limitations (see). ● Additional information on this website, bibliographical references and recommended references (see).

In a nutshell

● In the autumn and winter of 2023–2024, all autonomous communities in Spain offered immunization against RSV with nirsevimab. Uptake of this measure was excellent, with ≥90% coverage. ● The first evaluations of the effectiveness of nirsevimab in preventing hospitalizations for RSV-associated lower respiratory tract infection (LRTI) have just been published. ● The study was carried out in nine hospital centers in the Valencian Community, Murcia and Castile and Leon. ● The target population for immunization with nirsevimab (born from April 1, 2023) in these regions was 15 people..676 babies. Nirsevimab coverage ranged from 88.9% to 98.6%. ● During the study period (October 1, 2023 to January 10, 2024), there were 166 hospitalizations for LRTI, of which 95 were RSV-positive. Among them, 53% were immunized, whereas in non-RSV BRIV cases, 83% were immunized. ● Efficacy in pooled data (negative test design): 70.2% (95% CI: 38.3% to 88.5%). ● Efficacy in pooled data (sensitivity analysis using screening design): 84.4% (95% CI: 76.8% to 90.0%). ● Conclusion: Nirsevimab immunization was more than 70% effective in preventing hospitalizations in children under 9 months of age with RSV-associated LRTI. The data presented are preliminary and require further study.

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Introduction

In July 2023, the Ministry of Health published recommendations for the use of nirsevimab for the prevention of infections caused by respiratory syncytial virus (RSV) in newborns and infants. Previously, in March 2023, Galicia had already announced that it would include nirsevimab starting in the autumn of the same year (Martinón-Torres F, Euro Surveill 2023). Other communities have since made similar announcements. Finally, in October, all communities joined in and included universal RSV prophylaxis in their immunization programs for all children born on or after April 1, 2023.

The coverage achieved, as reported by some societies, is high, indicating excellent uptake of the intervention despite the novelty of the product used, nirsevimab, a synthetic monoclonal antibody.

Commented below first preliminary data on the effectiveness of nirsevimab in Spain.

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First data on the effectiveness of nirsevimab published in Spain

Commented study:

• Lopez-Lacorte M. et al. Early evaluation of the effectiveness of nirsevimab immunoprophylaxis during hospitalization for respiratory syncytial virus lower respiratory tract infections in infants, Spain, October 2023 – January 2024. Euro Surveill. 2024;29(6):pii=2400046.

This article presents the first evaluation of the effectiveness of nirsevimab in hospitalization for lower respiratory tract infections (LRTIs). acute lower respiratory tract infections) associated with RSV (IRVB-RSV) in children under 9 years of age·months in three Spanish Autonomous Communities.

The study was partly funded by the Carlos III Institute of Health through European funds from the Recovery, Transformation and Resilience Plan, and by the European Union -NextGenerationEU-.

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Target

To present a preliminary assessment of the effectiveness of nirsevimab in hospitalization for RSV-related LRTI in children

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Methodology

• The study was conducted from October 2023 to January 2024.
• Multicentre active hospital surveillance was carried out in nine hospitals located in three autonomous communities (five hospitals in three provinces of the Valencian Community, three in the Murcia region and one in Castile and León, Valladolid).
• In the reference regions, children born on April 1, 2023, eligible for vaccination, amounted to 15.676 (6.4% of the total Spanish population with the same disease). In patients hospitalized with respiratory infection, tests for the detection of RSV were carried out using a PCR test.
• Two designs were used to evaluate the efficacy of nirsevimab: a screening approach and a test-negative design.

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Results

A total of 166 hospitalizations for RRBI were included, with 73 cases having fewer than 3 hospitalizations.·one month of age. In 95 patients it was LRTI-RSV, of whom 53% were immunized. Among 71 non-RSV BRIV cases, 83% were immunized.

Table 1 (attached) shows nirsevimab immunization coverage and hospitalization of children with LRTI in the three study regions. Immunization coverage at each hospital is detailed (ranging from 78.7% to 98.6%), as well as the number of BRI and BRI-RSV hospitalizations. In addition, the percentage of immunized and unimmunized infants in both groups and the BRI-RSV rate per 1000 infants are reported.

Table 3 (attached) demonstrates the effectiveness of nirsevimab against infant hospitalization due to LRTI-RSV according to study sites and assessment method.

Efficiency with data grouped by evaluation method:

• The screening method found that the effectiveness was 86.9% in Murcia, 69.3% in Com. Valencia and 97.0% in Valladolid. Pooled analysis of data from three regions showed an effectiveness of 84.4% (95% CI: 76.8% to 90.0).·%) in the prevention of hospitalizations for LRTI-RSV in young children.
• If the test is negative, the grouped Com data. Valencia and Murcia show an effectiveness of 70.2% (95% CI: 38.3% to 88.5%).

The results show that immunization with nirsevimab was at least 70% effective in preventing hospitalizations in children under 9 years of age.·months with RSV-positive lower respiratory tract infections. However, it did not demonstrate protection against hospitalizations for non-RSV lower respiratory tract infections.

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Conclusions and limitations

• The authors suggest that nirsevimab may have a significant impact on RSV-related health, although more research is needed to confirm these preliminary results.
• The effectiveness of nirsevimab is important for public health decision making due to the impact of RSV in infants on the burden on healthcare systems during winter periods.
• The authors cite some limitations, such as variability in effectiveness estimates due to differences in RSV circulation, hospitalization policies, and case definitions.

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More information on this website

Bibliographical references and recommended references

• Lopez-Lacorte M, and others. Early evaluation of the effectiveness of nirsevimab immunoprophylaxis during hospitalization for respiratory syncytial virus lower respiratory tract infections in infants, Spain, October 2023 – January 2024. Euro Surveill. 2024;29(6):pii=2400046. ►Comment: CIDRAP, February 9, 2024
• Martinon-Torres F, and others. First lessons from implementing universal respiratory syncytial virus prophylaxis in infants with long-acting monoclonal antibodies, Galicia, Spain, September and October 2023. Euro Surveill. 2023;28(49):pii=2300606.

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