From the Guidelines
Beyfortus (nirsevimab) is a long-acting monoclonal antibody recommended for the prevention of respiratory syncytial virus (RSV) in infants and some young children, given as a single intramuscular injection, typically before or during the RSV season. The recommended dose is 50 mg for infants weighing less than 5 kg, and 100 mg for those weighing 5 kg or more, as stated in the Morbidity and Mortality Weekly Report 1. This single dose provides protection for about 5 months, covering the typical RSV season.
Indications for Use
Beyfortus is indicated for:
- All infants born during or entering their first RSV season
- Infants up to 24 months old who remain vulnerable to severe RSV disease, particularly those with underlying health conditions or premature infants, as highlighted in the study by 2 The medication works by directly providing antibodies against RSV, offering immediate protection without relying on the infant's immune system to develop its own antibodies.
Benefits and Risks
This is particularly beneficial for premature infants or those with underlying health conditions who may be at higher risk for severe RSV disease, as noted in the recommendations by 3. Side effects are generally mild and may include injection site reactions, rash, or fever. As with any medication, parents should discuss potential risks and benefits with their healthcare provider. Beyfortus represents a significant advance in RSV prevention, offering a more convenient and potentially more effective alternative to the previously used monthly palivizumab injections for high-risk infants. According to 1, the Advisory Committee on Immunization Practices (ACIP) recommends 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.
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 (Nirsevimab) is a monoclonal antibody used to help prevent a serious lung disease caused by Respiratory Syncytial Virus (RSV) in newborns, babies under 1 year of age, and children up to 24 months of age who remain at risk of severe RSV disease. It contains nirsevimab-alip and is administered via intramuscular injection. 4
From the Research
What is Beyfortus (Nirsevimab)?
- Beyfortus, also known as Nirsevimab, is a monoclonal antibody with an extended half-life that is being developed to protect infants for an entire RSV season with a single intramuscular dose 5, 6.
- It is designed to prevent lower respiratory tract illness caused by respiratory syncytial virus (RSV) infections in infants 6.
- Nirsevimab targets the RSV F protein and has been shown to be effective in preventing RSV-associated lower respiratory tract infection in healthy preterm and term infants, as well as in high-risk infants 5, 7, 8.
Mechanism of Action
- Nirsevimab works by binding to the RSV F protein, preventing the virus from entering host cells and replicating 6.
- It has an extended half-life, allowing it to provide protection against RSV for an entire season with a single dose 5, 6.
Efficacy and Safety
- Clinical trials have shown that Nirsevimab is effective in preventing RSV-associated lower respiratory tract infection and hospitalization in infants 5, 7, 9, 8.
- The efficacy of Nirsevimab has been demonstrated in both healthy preterm and term infants, as well as in high-risk infants with chronic lung disease or congenital heart disease 7, 8.
- Nirsevimab has been shown to be safe and well-tolerated, with a low risk of adverse events 5, 7, 8.
Recommendations and Approvals
- The Centers for Disease Control and Prevention (CDC) has recommended Nirsevimab for all infants younger than 8 months of age entering or born during the RSV season, as well as for high-risk infants 8-19 months of age entering their second season 7.
- Nirsevimab has been approved for use in several countries, including the United States, for the prevention of RSV-associated lower respiratory tract infection in infants 9.