Beyfortus® (nirsevimab-alip)—a direct immunization for the prevention of RSV-LRTI in infants2
Beyfortus is a monoclonal antibody indicated for the prevention of RSV-LRTI in infants. This direct immunization is not a vaccine, but a preventive antibody that has been trusted and preferred by HCPs since its launch.1-3
11 million+ infants immunized1*
Data from real-world and clinical studies1*
*Supported by global estimated exposure based on calculation from sales volume data (01 September 2023 through 31 October 2025). The number of children exposed is estimated based on distribution of recommended dose of Beyfortus administered, considering body weight, season of administration (1st or 2nd), and immunization plan.1
Ready to order Beyfortus?
Beyfortus is available through the Vaccines for Children (VFC) Program, VaccineShop,* VaxServe, and select wholesalers and distributors.† Simply create an account on these platforms to order Beyfortus with immediate shipping.
*All direct customers on VaccineShop will receive a 2% discount and 90-day billing terms. Excludes wholesale, distributor, and public orders.
†Beyfortus 50 mg and 100 mg Injection is available to purchase through wholesalers and distributors. Please call 1-800-VACCINE (1-800-822-2463) for more information.
‡Based on available information from national payer organizations.
The monoclonal antibody with the longest half-life2,4,5
Beyfortus is approved for the prevention of RSV disease in infants
*Local epidemiology will define start of RSV season in your area.
†Recommended dose for first season only. Please consult the accompanying Prescribing Information for complete dosing information, including children undergoing cardiac surgery with cardiopulmonary bypass and for those entering a second RSV season who remain at increased risk.
Frequently Asked Questions
Beyfortus is not a vaccine. It’s a preventive antibody that helps infants’ maturing immune systems by providing antibodies that help protect against RSV disease.2
Beyfortus is a single dose for the vast majority of infants, that is timed to the RSV season2:
- <5 kg weight = 50 mg dose
- ≥5 kg weight = 100 mg dose
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.2
Second season: children up to 24 months of age, regardless of body weight, who remain vulnerable to severe RSV disease2:
- 1 x 200 mg dose administered as 2 IM injections (2 x 100 mg)
Yes, a single dose is intended to protect infants for an entire RSV season. Protection extends through 5 months, the length of a typical RSV season.2,6*
*Based on clinical data.
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 Reactions Including Anaphylaxis: Serious hypersensitivity reactions have been reported following Beyfortus administration. These reactions included urticaria, dyspnea, cyanosis, and/or hypotonia. Anaphylaxis has been observed with human immunoglobulin G1 (IgG1) monoclonal antibodies. If signs and symptoms of anaphylaxis or other clinically significant hypersensitivity reactions occur, initiate appropriate treatment.
- 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.
HCP, healthcare professional; IM, intramuscular; LRTI, lower respiratory tract infection; MOA, mechanism of action; RSV, respiratory syncytial virus.
Important Safety Information
References: 1. Data on File. Sanofi. 2. Beyfortus (nirsevimab-alip). Prescribing Information. Sanofi. 3. RSV immunization guidance for infants and young children. Centers for Disease Control and Prevention. Updated August 18, 2025. Accessed June 1, 2026. https://www.cdc.gov/rsv/hcp/vaccine-clinical-guidance/infants-young-children.html 4. Enflonsia (clesrovimab-cfor). Prescribing Information. Merck & Co Inc. 5. Synagis (palivizumab). Prescribing Information. Sobi. 6. Obando-Pacheco P, Justicia-Grande AJ, Rivero-Calle I, et al. Respiratory syncytial virus seasonality: a global overview. J Infect Dis. 2018;217(9):1356-1364.
