Discover Beyfortus (nirsevimab-alip) 50 mg and 100 mg Injection

Beyfortus is the only antibody designed for season-long RSV disease protection that extends through 5 months¹

Beyfortus inhibiting RSV F (fusion) protein image

Direct, Long-Acting Antibody¹


Antibody administration directly to infant; does not rely on infant’s maturing immune system¹


  • Long-acting antibody: modified to extend its half-life¹
  • RSV disease protection through 5 months based on clinical data¹


Monoclonal antibody (mAb) that provides passive immunity by inhibiting RSV F (fusion) protein to prevent viral entry into cells¹

The first and only antibody designed to protect all infants¹

Beyfortus was approved by the FDA in July of 2023 for use in¹˒²:

  • Neonates and infants born during or entering their first RSV season
  • Children up to 24 months who remain vulnerable to severe RSV disease through their second RSV season

FDA approved for a broad range of infant populations entering their first RSV season, including¹:
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Healthy or With Underlying Conditions

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Full Term or Preterm

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During or Entering the RSV season*

More on Beyfortus dosing and administration

  • For neonates and infants born during or entering their first RSV season, the recommended dose is 50 mg for infants <5 kg or 100 mg for infants ≥5 kg via intramuscular administration
  • For children up to 24 months of age who remain at increased risk for severe RSV disease their second season, the recommended dose is a single 200 mg dose administered as two IM injections (2 x 100 mg)
  • For children undergoing cardiac surgery with cardiopulmonary bypass, an additional dose is recommended as soon as infant is stable after surgery. Please consult the Prescribing Information for complete information on dosing in this circumstance.

The efficacy and safety of Beyfortus was evaluated in randomized, double-blind, multicenter trials for the prevention of RSV lower respiratory tract infection:


Trial 04
(Phase 3 MELODY)

Healthy term and late preterm infants (≥35 wGA)
changing baby

Trial 03
(Phase 2b)

Healthy preterm infants (≥29 to <35 wGA)

Trial 05
(Phase 2/3 MEDLEY)

Preterm Infants (<35 wGA) and infants born with CLD of prematurity or hemodynamically significant CHD

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Cost and Coverage With Beyfortus

beyfortus pacifier

Demonstrated Safety and Efficacy Profile¹


Beyfortus is indicated for the prevention of respiratory syncytial virus (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 vulnerable to severe RSV disease through their second RSV season.

Important safety information


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

Warnings and Precautions

  • Hypersensitivity Including Anaphylaxis: Serious hypersensitivity reactions, including anaphylaxis, have been observed with other human IgG1 monoclonal antibodies. If signs and symptoms of a clinically significant hypersensitivity reaction or anaphylaxis occur, initiate appropriate medications and/or supportive therapy.
  • Use in Individuals with Clinically Significant Bleeding Disorders: As with other IM injections, Beyfortus should be given with caution to infants and children with thrombocytopenia, any coagulation disorder or to individuals on anticoagulation therapy.

Most common adverse reactions with Beyfortus were rash (0.9%) and injection site reactions (0.3%).

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