Beyfortus injection for preventing severe RSV disease in infants and young children

Beyfortus is an injectable medicine designed to prevent lower respiratory tract disease caused by Respiratory Syncytial Virus (RSV) in infants and young children. It is given as a monoclonal antibody targeting RSV, helping protect babies during their first or second RSV season when they are most vulnerable. The product is administered by healthcare providers as an intramuscular injection.

Beyfortus is approved for preventing RSV lower respiratory tract disease in:

• Neonates and infants born during or entering their first RSV season.
• Children up to 24 months of age who remain at increased risk for severe RSV disease during their second RSV season.

nirsevimab-alip

Beyfortus contains nirsevimab-alip, a monoclonal antibody that blocks the fusion protein of RSV. By inhibiting the fusion of the virus with host cells, it prevents RSV from entering respiratory cells and causing infection, thereby reducing the risk of severe lower respiratory tract illness in infants and young children.

Recommended Dosage

Administer by intramuscular injection according to body weight and RSV season:

• First RSV season (neonates and infants):
• Less than 5 kg: 50 mg as a single IM injection.
• 5 kg or more: 100 mg as a single IM injection.
• Second RSV season (children up to 24 months at increased risk): 200 mg total, administered as two 100 mg IM injections.

Additional Dose for Cardiac Surgery

Children undergoing cardiopulmonary bypass surgery may require an additional BEYFORTUS dose once stable post-surgery, to maintain protective serum levels. Dosage depends on timing since previous dose and RSV season:

• First RSV season:
• If surgery within 90 days of prior dose: weight-based dose per Table 1 (50 mg if <5 kg; 100 mg if ≥5 kg).
• If more than 90 days since prior dose: 50 mg regardless of weight.
• Second RSV season:
• If surgery within 90 days of prior dose: 200 mg regardless of weight.
• If more than 90 days since prior dose: 100 mg regardless of weight.

Administration Instructions

• Check that the solution is clear to opalescent and colorless to yellow, without visible particulates or discoloration.
• Use the correct pre-filled syringe (50 mg with purple plunger rod or 100 mg with light blue plunger rod) based on body weight.
• Do not use if the syringe is damaged, dropped, expired, or if carton seal is broken.
• Administer preferably in the anterolateral thigh muscle; avoid gluteal muscle to prevent sciatic nerve injury.
• If two injections are required, use separate injection sites.
• Can be given concomitantly with childhood vaccines, but use separate syringes and injection sites.

Beyfortus is contraindicated in infants and children with a known history of serious hypersensitivity reactions, including anaphylaxis, to nirsevimab-alip or any of its ingredients.

Hypersensitivity and Anaphylaxis

Serious allergic reactions, including anaphylaxis, urticaria (rash), breathing difficulties, cyanosis, and hypotonia, have been observed after Beyfortus administration. Immediate treatment is required if such reactions occur.

Caution in Bleeding Disorders

Use with care in infants or children with thrombocytopenia, coagulation disorders, or those receiving anticoagulant therapy, as with any intramuscular injection.

The most common side effects reported were rash (~0.9%) and injection site reactions (~0.3%). Other adverse reactions reported include hypersensitivity reactions such as rash, breathing difficulties, and anaphylaxis. Most side effects were mild to moderate.

Beyfortus can be administered together with childhood vaccines, but separate syringes and injection sites should be used. It should not be mixed in the same syringe or vial with other vaccines or medications. There is no available data on co-administration with other immunoglobulin products. Palivizumab should not be given to infants who have already received Beyfortus during the same RSV season.

Store Beyfortus as per manufacturer instructions (not explicitly detailed in the source). Inspect visually before use to ensure solution clarity and no particulate matter. Do not use if the product is cloudy, discolored, or contains visible particles.