Dosing and Administration

Beyfortus (nirsevimab-alip) 50 mg and 100 mg injection is a single dose timed to the RSV season for the vast majority of infants¹

The ideal timing for Beyfortus dosing is just before or near the start of the RSV season or from birth for infants born shortly before or during the RSV season.¹
Scheduling a single dose of Beyfortus Chart
Provides passive immunization that extends through 5 months, the typical length of the RSV season, regardless of birth month1,2
Hospital: If not given at the hospital prior to discharge, administer Beyfortus at the first well-baby visit, ideally within 1 week of birth

Office: May be given at regularly scheduled 2-, 4-, or 6-month well-baby visits


  • For children undergoing cardiac surgery with cardiopulmonary bypass, an additional dose of Beyfortus is recommended as soon as the child is stable after surgery; please consult the Prescribing Information for complete information on dosing in these circumstances

  • Children up to 24 months of age who remain vulnerable through their second RSV season:
    - 1 x 200 mg dose administered as 2 IM injections (2 x 100 mg)

Due to variability in RSV seasonality, there are regional considerations for Beyfortus administration³

ACIP Regional Administration Guidelines³


  • Because the timing of the onset, peak, and decline of RSV activity might vary geographically, providers can adjust administration schedules based on local epidemiology
      • RSV seasonality in tropical climates (including southern Florida, Guam, Hawaii, Puerto Rico, US-affiliated Pacific Islands, and US Virgin Islands) might differ
      • In Alaska, RSV seasonality is less predictable, and the duration of RSV activity is often longer than the national average duration

  • Providers in these jurisdictions should consult state, local, or territorial guidance on timing of Beyfortus administration

Second RSV Season Guidelines³


Infants and children aged 8-19 months with increased risk for severe disease who are recommended to receive Beyfortus when entering their second RSV season include:
  • Children with chronic lung disease of prematurity who required medical support (chronic corticosteroid therapy, diuretic therapy, or supplemental oxygen) any time during the 6-month period before the start of the second RSV season
  • Severely immunocompromised children
  • Children with cystic fibrosis who have either

  1. manifestations of severe lung disease (previous hospitalization for pulmonary exacerbation in the first year of life or abnormalities on chest imaging that persist when stable), or
  2. weight-for-length <10th percentile

  • American Indian or Alaska Native children

Single-dose, pre-filled syringe for convenient administration¹

A single dose for the vast majority of infants based on weight¹

< 5kg

beyfortus 50 mg

≥ 5kg

beyfortus 100 mg

First RSV season: neonates and infants

The recommended dosage of Beyfortus for neonates and infants born during or entering their first RSV season is based on body weight and is administered as a single intramuscular (IM) injection.

Dosage of Beyfortus in neonates and infants born during or entering their first RSV season

Body Weight at the Time of DosingRecommended Dosage
<5 kg50 mg by IM injection
≥5 kg100 mg by IM injection

Second RSV season: Children who remain vulnerable to severe RSV disease

For children up to 24 months of age who remain at increased risk for severe RSV in their second RSV season, the recommended dosage of Beyfortus is a single 200 mg dose administered as two IM injections (2 x 100 mg).

Children undergoing cardiac surgery with cardiopulmonary bypass

For children undergoing cardiac surgery with cardiopulmonary bypass, an additional dose is recommended as soon as the child is stable after surgery. Please consult the Prescribing Information for complete information on dosing in this circumstance.
Can be administered concomitantly with any childhood vaccines
There is limited experience of Beyfortus coadministration with vaccines. In clinical trials, when Beyfortus was given with routine childhood vaccines, the safety and reactogenicity profile of the coadministered regimen was similar to the childhood vaccines given alone. Beyfortus should not be mixed with any vaccine in the same syringe or vial. When administered concomitantly with injectable vaccines, they should be given with separate syringes and at different injection sites.

Practical considerations for Beyfortus

Syringe icon

How should Beyfortus be administered?¹


  • Beyfortus is for intramuscular injection only, preferably in the anterolateral aspect of the thigh
  • The entire contents of the syringe should be administered intramuscularly
  • The gluteal muscle should not be used routinely as an injection site because of the risk of damage to the sciatic nerve
Refrigerator icon

How should Beyfortus be stored?¹


  • Store in a refrigerator 36° F to 46° F (2° C to 8° C)
  • Beyfortus may be kept at room temperature 68°F to 77°F (20°C to 25°C) for a maximum of 8 hours. After removal from the refrigerator, Beyfortus must be used within 8 hours or discarded
  • Do not freeze
  • Do not shake or expose to direct heat
  • Store in original carton to protect from light until time of use

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Demonstrated Safety and Efficacy Profile¹

Indication

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

Contraindication

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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