From the Guidelines
Beyfortus (nirsevimab) is the preferred choice over Synagis (palivizumab) for preventing respiratory syncytial virus (RSV) infections in infants due to its single-dose administration and broader protection. The main difference between Beyfortus and Synagis lies in their administration and indications. Beyfortus requires only a single intramuscular injection that provides protection for the entire RSV season, whereas Synagis requires monthly injections throughout the RSV season (typically 5 doses) 1.
Key Points
- Beyfortus is recommended for all infants under 8 months born during or entering their first RSV season, and for high-risk infants up to 19 months 1.
- Synagis is now primarily reserved for specific high-risk groups such as infants with severe immunocompromise, certain congenital heart defects, or chronic lung disease requiring medical therapy.
- The dosage for Beyfortus is 50 mg for infants weighing less than 5 kg and 100 mg for those weighing 5 kg or more.
- Both medications work by binding to the RSV F protein, preventing viral entry into cells, but Beyfortus has a longer half-life allowing for the single-dose approach.
- Replacing palivizumab with nirsevimab is expected to be cost saving, and ACIP recommends nirsevimab for eligible children entering their second RSV season, similar to groups of children recommended by AAP for palivizumab during their second RSV season 1. Some studies have shown that certain populations, such as American Indian or Alaska Native (AI/AN) children, experience high rates of severe RSV disease, and ACIP also recommends nirsevimab for AI/AN children entering their second RSV season 1. Overall, Beyfortus offers broader protection with less frequent dosing, making it more convenient and cost-effective compared to Synagis.
From the Research
Comparison of Beyfortus (Nirsevimab) and Synagis (Palivizumab)
- Beyfortus (Nirsevimab) is a monoclonal antibody with an extended half-life, developed to protect infants for an entire RSV season with a single dose 2.
- Synagis (Palivizumab) is an RSV-specific prophylactic for use in high-risk infants, but treatment requires monthly injections and only modestly reduces hospitalization 2.
- Studies have shown that Nirsevimab is effective in preventing hospitalizations due to RSV in infants, with an efficacy of 83.2% (95% CI, 67.8 to 92.0; P<0.001) 3.
- Nirsevimab has also been shown to be effective in preventing very severe RSV-associated lower respiratory tract infection, with an efficacy of 75.7% (95% CI, 32.8 to 92.9; P = 0.004) 3.
- A comparison of RSV neutralizing antibody levels between Nirsevimab and Palivizumab found that Nirsevimab confers ∼10-fold higher and more sustained RSV nAb levels relative to Palivizumab 4.
- The pharmacokinetic data of Nirsevimab support its efficacy extrapolation to infants with chronic lung disease, congenital heart disease, or extreme prematurity 5.
- Nirsevimab has the potential to change the landscape of infant RSV disease by reducing a major cause of infant morbidity and the consequent burden on caregivers, clinicians, and health-care providers 5, 3, 6.
Key Differences
- Nirsevimab requires a single dose to last the entire RSV season, whereas Palivizumab requires monthly injections 2, 4.
- Nirsevimab can be given to term, preterm, and high-risk infants, whereas Palivizumab is limited to extremely vulnerable infants in resource-rich settings due to its high cost 2, 6.
- Nirsevimab has been shown to be more effective than Palivizumab in preventing hospitalizations due to RSV in infants 3, 4.