From the Guidelines
Beyfortus is a long-acting monoclonal antibody, specifically nirsevimab, approved for the prevention of respiratory syncytial virus (RSV)–associated lower respiratory tract infection (LRTI) among infants and children aged <24 months. According to the most recent guidelines from the Advisory Committee on Immunization Practices (ACIP) in 2023 1, Beyfortus is administered as a 1-dose intramuscular injection shortly before or during the RSV season. The key benefits of Beyfortus include its long-acting nature, requiring only a single dose per season, which is more convenient for families compared to other preventive medications like palivizumab (Synagis) that require monthly injections.
The recommendation for Beyfortus is based on its efficacy and safety profile, as assessed using the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) framework 1. The ACIP recommended nirsevimab for infants aged <8 months who are born during or entering their first RSV season and for infants and children aged 8–19 months who are at increased risk for severe RSV disease and are entering their second RSV season.
Some of the key points about Beyfortus include:
- It is used for the prevention of RSV-associated LRTI among high-risk infants and young children.
- It is administered as a single intramuscular injection.
- The dose is not specified in the provided evidence, but it is typically based on the infant's weight.
- It provides passive immunity against RSV for approximately 5 months, covering the typical RSV season.
- It is particularly important for premature infants, those with certain heart or lung conditions, and other high-risk groups.
Overall, Beyfortus (nirsevimab) is a valuable tool in the prevention of RSV infections in high-risk infants and young children, and its use is recommended by the ACIP based on the most recent evidence 1.
From the FDA Drug Label
BEYFORTUS is a prescription medicine that is used to help prevent a serious lung disease caused by Respiratory Syncytial Virus (RSV) in: • newborns and babies under 1 year of age born during or entering their first RSV season • children up to 24 months of age who remain at risk of severe RSV disease through their second RSV season. BEYFORTUS is an antibody that contains nirsevimab-alip which is used to help prevent RSV disease for 5 months.
Beyfortus is a prescription medicine used to prevent serious lung disease caused by Respiratory Syncytial Virus (RSV) in newborns, babies under 1 year, and children up to 24 months who remain at risk of severe RSV disease. It is an antibody that contains nirsevimab-alip. 2
From the Research
Definition of Beyfortus
- Beyfortus, also known as nirsevimab, is a long-acting intramuscular recombinant neutralising human IgG1ĸ monoclonal antibody to the prefusion conformation of the respiratory syncytial virus (RSV) F protein 3.
- It has been modified with a triple amino acid substitution in the Fc region to extend the serum half-life, allowing administration of nirsevimab as a single dose to cover the RSV season 3.
Purpose and Benefits
- Beyfortus is being jointly developed by AstraZeneca and Sanofi for the prevention of RSV disease 3.
- It has been approved in the EU and UK for the prevention of RSV lower respiratory tract disease in neonates and infants during their first RSV season 3.
- Nirsevimab offers consistent and sustained protection against hospitalisation due to RSV-associated lower respiratory tract infection for at least 6 months 4.
- It is expected to significantly reduce the health and economic burdens of RSV 5.
Administration and Efficacy
- Beyfortus is administered as a single intramuscular dose of 50 mg for children <5 kg or 100 mg for children ≥5 kg 4.
- The efficacy of nirsevimab at 180 days after dosing has been evaluated in a randomised, controlled, phase 3b trial, showing an efficacy of 82.7% (95% CI 67.8-91.5; p<0.0001) in preventing hospitalisation due to RSV-associated lower respiratory tract infection 4.
- Nirsevimab has been shown to reduce infant hospitalisations due to RSV-associated lower respiratory tract infection through the RSV season 4.