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Frequently Asked Questions About Beyfortus®


About Beyfortus

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Dosing & administration

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ACOG, American College of Obstetricians and Gynecologists; IM, intramuscular; LRTD, lower respiratory tract disease; RSV, respiratory syncytial virus.

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 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.

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

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

Indication

References: 1. Arriola CS, Kim L, Langley G, et al. Estimated burden of community-onset respiratory syncytial virus-associated hospitalizations among children aged <2 years in the United States, 2014-15. J Pediatric Infect Dis Soc. 2020;9(5):587-595. 2. RSV in infants and young children. Centers for Disease Control and Prevention. Updated February 20, 2026. Accessed June 11, 2026. https://www.cdc.gov/rsv/infants-young-children/index.html 3. Beyfortus (nirsevimab-alip). Prescribing Information. Sanofi. 4. 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. 5. FDA approves Beyfortus™ (nirsevimab-alip) to protect infants against RSV disease. Press Release. Sanofi. July 17, 2023. Accessed May 26, 2025. https://www.sanofi.com/en/media-room/press-releases/2023/2023-07-17-17-00-00-2705911 6. Brady T, Cayatte C, Roe TL, et al. Fc-mediated functions of nirsevimab complement direct respiratory syncytial virus neutralization but are not required for optimal prophylactic protection. Front Immunol. 2023;14:1283120. 7. Domachowske J, Khan AA, Esser MT, et al. Safety, tolerability and pharmacokinetics of MEDI8897, an extended half-life single-dose respiratory syncytial virus prefusion F-targeting monoclonal antibody administered as a single dose to healthy preterm infants. Pediatr Infect Dis J. 2018;37(9):886-892. 8. Addendum: Special considerations for COVID-19 vaccine and nirsevimab. Centers for Disease Control and Prevention. Updated March 29, 2024. Accessed June 11, 2026. https://www.cdc.gov/vaccines-for-children/media/pdfs/2024/08/operations-guide-covid-19-addendum-2024-4-2_002-508.pdf 9. Vaccines for Children (VFC) Program: information for parents. Centers for Disease Control and Prevention. Updated September 30, 2025. Accessed June 11, 2026. https://www.cdc.gov/vaccines-for-children/vfc-information-for-parents/index.html 10. Immunizations to protect infants. Centers for Disease Control and Prevention. Updated August 18, 2025. Accessed June 11, 2026. https://www.cdc.gov/rsv/vaccines/protect-infants.html 11. Maternal respiratory syncytial virus vaccination. American College of Obstetricians and Gynecologists. Updated October 2025. Accessed June 11, 2026. https://www.acog.org/clinical/clinical-guidance/practice-advisory/articles/2023/09/maternal-respiratory-syncytial-virus-vaccination

MAT-US-2310577-v9.0-08/2026