Version July 2025
Respiratory syncytial virus (RSV), prevention: Note: Administer nirsevimab within 1 week of birth for neonates born shortly before or during the RSV season, ideally during the birth hospitalization (Ref).
Patient's first RSV season:
Preterm and term neonates:
Weight <5 kg: IM: 50 mg as a single dose.
Patients who undergo cardiopulmonary bypass after dose: IM: Administer a 50 mg dose as soon as patient is stable after surgery (regardless of time elapsed).
Weight ≥5 kg: IM: 100 mg as a single dose.
Patients who undergo cardiopulmonary bypass after dose: Administer an additional dose as follows as soon as patient is stable after surgery:
≤90 days since initial dose: IM: 100 mg as a single dose.
>90 days since initial dose: IM: 50 mg as a single dose.
Respiratory syncytial virus (RSV), prevention: Note: Administer shortly before the RSV season begins; if not administered before start of season, may administer at any time during the season (Ref).
Patient's first RSV season: Note: While nirsevimab is FDA approved for all infants in their first RSV season, ACIP and AAP recommendations specify use in infants <8 months of age (Ref).
Infants:
Weight <5 kg: IM: 50 mg as a single dose.
Patients who undergo cardiopulmonary bypass after dose: IM: Administer a 50 mg dose as soon as patient is stable after surgery (regardless of time elapsed).
Weight ≥5 kg: IM: 100 mg as a single dose.
Patients who undergo cardiopulmonary bypass after dose: Administer an additional dose as follows as soon as patient is stable after surgery:
≤90 days since initial dose: IM: 100 mg as a single dose.
>90 days since initial dose: IM: 50 mg as a single dose.
Patient's second RSV season: Note: While nirsevimab is FDA approved for patients up to 24 months of age who remain at increased risk for severe disease during their second RSV season, ACIP and AAP recommend second-season dosing only for patients 8 to ≤19 months of age who are at increased risk for severe disease (Ref).
Infants and Children <24 months: IM: 200 mg as a single dose (Ref).
Patients who undergo cardiopulmonary bypass after dose: Administer an additional dose as follows as soon as patient is stable after surgery:
≤90 days since initial dose: IM: 200 mg as a single dose.
>90 days since initial dose: IM: 100 mg as a single dose.
No dosage adjustments are provided in the manufacturer's labeling; however, nirsevimab is not cleared in the kidney and change in kidney function is not expected to influence clearance, so dosage adjustment is likely not needed.
No dosage adjustments are provided in the manufacturer's labeling; however, nirsevimab is not cleared in the liver and change in liver function is not expected to influence clearance, so dosage adjustment is likely not needed.
The following adverse drug reactions and incidences are derived from product labeling unless otherwise specified. Adverse reactions reported in neonates and infants.
<1%:
Dermatologic: Skin rash (0.9%) (table 1)
|
Drug (Nirsevimab) |
Placebo |
Population |
Dose |
Dosage Form |
Indication |
Number of Patients (Nirsevimab) |
Number of Patients (Placebo) |
|---|---|---|---|---|---|---|---|
|
0.9% |
0.6% |
Neonates and Infants |
50 or 100 mg |
IM |
Prevention of respiratory syncytial virus |
2,570 |
1,284 |
Local: Injection-site reaction (0.3%) (table 2)
|
Drug (Nirsevimab) |
Placebo |
Population |
Dose |
Dosage Form |
Indication |
Number of Patients (Nirsevimab) |
Number of Patients (Placebo) |
|---|---|---|---|---|---|---|---|
|
0.3% |
0% |
Neonates and Infants |
50 or 100 mg |
IM |
Prevention of respiratory syncytial virus |
2,570 |
1,284 |
Postmarketing: Hypersensitivity: Hypersensitivity reaction (including severe hypersensitivity reaction)
Serious hypersensitivity (eg, anaphylaxis) to nirsevimab or any component of the formulation.
Concerns related to adverse effects:
• Hypersensitivity reactions: Serious hypersensitivity reactions, including cyanosis, dyspnea, hypotonia, and/or urticaria, have been reported. Anaphylaxis has been reported with other human IgG1 monoclonal antibodies. If signs or symptoms of anaphylaxis or significant hypersensitivity reaction occur, administer appropriate medications (eg, epinephrine) and provide supportive care as required.
Disease-related concerns:
• Bleeding disorders: Use with caution in patients with a history of bleeding disorders (including thrombocytopenia); bleeding/hematoma may occur from IM administration.
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Solution Prefilled Syringe, Intramuscular [preservative free]:
Beyfortus: Nirsevimab-alip 100 mg/mL (1 mL); Nirsevimab-alip 50 mg/0.5 mL (0.5 mL) [contains polysorbate 80]
No
Solution Prefilled Syringe (Beyfortus Intramuscular)
50 mg/0.5 mL (per 0.5 mL): $667.36
100 mg/mL (per mL): $667.36
Disclaimer: A representative AWP (Average Wholesale Price) price or price range is provided as reference price only. A range is provided when more than one manufacturer's AWP price is available and uses the low and high price reported by the manufacturers to determine the range. The pricing data should be used for benchmarking purposes only, and as such should not be used alone to set or adjudicate any prices for reimbursement or purchasing functions or considered to be an exact price for a single product and/or manufacturer. Medi-Span expressly disclaims all warranties of any kind or nature, whether express or implied, and assumes no liability with respect to accuracy of price or price range data published in its solutions. In no event shall Medi-Span be liable for special, indirect, incidental, or consequential damages arising from use of price or price range data. Pricing data is updated monthly.
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Solution Prefilled Syringe, Intramuscular:
Beyfortus: Nirsevimab-alip 100 mg/mL (1 mL); Nirsevimab-alip 50 mg/0.5 mL (0.5 mL) [contains polysorbate 80]
Note: Intended for administration by a health professional only.
Parenteral: IM: Solution should be clear to opalescent, colorless to yellow. Do not use prefilled syringe if it has been dropped or damaged or if the liquid is cloudy, discolored, or contains large particles or foreign particulate matter. Administer IM in the anterolateral aspect of the thigh (Ref); for patients ≥1 year of age, injection may also be performed in the deltoid muscle if the muscle mass is adequate (Ref). Two injections are required to make the total 200 mg dose; different injection sites should be used. Do not routinely inject in the gluteal muscle because of risk of damage to the sciatic nerve. Note: It is not recommended to split a single 100 mg manufacturer-filled syringe into two 50 mg doses, or to administer two 50 mg doses in place of a single 100 mg dose (Ref).
Administration deviations:
Infants ≥8 months and Children ≤19 months of age (second RSV season): If a patient who should have received 200 mg received only 100 mg (half dose), administer the remaining 100 mg dose as soon as possible, and no later than the end of the season (Ref).
Store intact vials between 2°C to 8°C (36°F to 46°F) in original carton to protect from light. May be kept at 20°C to 25°C (68°F to 77°F) for a maximum of 8 hours. After removal from the refrigerator, must be used within 8 hours or discarded. Do not freeze, shake, or expose to heat.
In the United States, caregivers of patients receiving nirsevimab through the Vaccines for Children program must be provided the appropriate CDC-approved Immunization Information Statement (IIS) before nirsevimab administration. The AAP recommends that the IIS be provided to all families, either electronically or hard copy, to review at home or in-office (AAP 2023). The IIS is available at https://www.cdc.gov/vaccines/vpd/rsv/immunization-information-statement.html.
Prevention of respiratory syncytial virus (RSV) lower respiratory tract disease during a patient's first RSV season (FDA approved in neonates and infants); prevention of RSV lower respiratory tract disease during a patient's second RSV season if they remain vulnerable to severe RSV disease (FDA approved in children <24 months of age).
ACIP and AAP recommend nirsevimab use beginning shortly before and during the RSV season (typically October through the end of March in most of the continental United States, but may be adjusted based on local epidemiology) in the following patients (Red Book [AAP 2024]; ACIP [Jones 2023]):
• All infants <8 months of age prior to or during their first RSV season
Note: Nirsevimab is not needed for most infants born at ≥34 weeks gestation whose mothers received RSVpreF (Abrysvo) vaccination during their pregnancy ≥14 days prior to birth. However, nirsevimab may be considered for infants born to vaccinated mothers when the potential incremental benefit of administration is warranted, based on the health care provider's clinical judgment. These situations might include, but are not limited to, the following (AAP 2024a; ACIP [Fleming-Dutra 2023]):
- Infants born to mothers who might not have mounted an adequate immune response to vaccination (eg, persons with immunocompromising conditions), or who have conditions associated with reduced transplacental antibody transfer (eg, persons living with HIV infection)
- Infants who might have experienced loss of maternal antibodies, such as those who have undergone cardiopulmonary bypass or extracorporeal membrane oxygenation
- Infants with substantially increased risk for severe RSV disease (eg, hemodynamically significant congenital heart disease, intensive care admission requiring oxygen at hospital discharge)
• Infants ≥8 months and children ≤19 months of age entering their second RSV season who are at an increased risk for severe RSV disease due to one of the following:
- Chronic lung disease of prematurity requiring medical support (chronic corticosteroid therapy, diuretic therapy, or supplemental oxygen) any time during the 6-month period before the start of the RSV season
- Severe immunocompromise
- Cystic fibrosis with either manifestations of severe lung disease (eg, previous hospitalization for pulmonary exacerbation in the first year of life or abnormalities on chest imaging that persist when stable) or weight-for-length <10th percentile
- American Indian or Alaska Native
None known.
Note: Interacting drugs may not be individually listed below if they are part of a group interaction (eg, individual drugs within “CYP3A4 Inducers [Strong]” are NOT listed). For a complete list of drug interactions by individual drug name and detailed management recommendations, use the drug interactions program by clicking on the “Launch drug interactions program” link above.
Note: Interacting drugs may not be individually listed below if they are part of a group interaction (eg, individual drugs within “CYP3A4 Inducers [Strong]” are NOT listed). For a complete list of drug interactions by individual drug name and detailed management recommendations, use the drug interactions program
Efgartigimod Alfa: May decrease therapeutic effects of Fc Receptor-Binding Agents. Risk C: Monitor
Nipocalimab: May decrease therapeutic effects of Fc Receptor-Binding Agents. Risk C: Monitor
Rozanolixizumab: May decrease therapeutic effects of Fc Receptor-Binding Agents. Risk C: Monitor
Nirsevimab is not approved for use in patients of reproductive potential.
Observe for hypersensitivity reaction.
Nirsevimab, a respiratory syncytial virus F protein-directed fusion inhibitor, is a human immunoglobulin G1 (IgG1) kappa monoclonal antibody with antirespiratory syncytial virus activity that provides passive immunization.
Anti-infective considerations:
Parameters associated with efficacy: AUC: >12.8 days•mg/mL (Jorgenson 2023; Simões 2023; manufacturer's labeling).
