Compare Options to Prevent RSV in Infants

Please see CDC recommendations for prioritizing nirsevimab 100 mg doses due to limited supply during the 2023-2024 RSV season.

The approval of Abrysvo is raising questions about nirsevimab use for respiratory syncytial virus (RSV) prevention after birth.

The RSV vaccine Abrysvo can now be given in pregnancy...generally from September through January if moms are 32 to 36 weeks gestation. The other RSV vaccine, Arexvy, isn’t approved for use in pregnancy.

Nirsevimab (Beyfortus) is a monoclonal antibody for infants under 8 months entering their first RSV season...generally October through March.

Think of nirsevimab like palivizumab (Synagis)...but given as a one-time dose.

It’s too soon to say whether vaccinating moms with Abrysvo or giving babies nirsevimab is more effective. Either helps protect the baby for the RSV season...but there aren’t head-to-head data.

Work with your pediatric and neonatology colleagues to create a plan to prevent RSV in infants born at or admitted to your hospital.

When moms are admitted in labor, document if they received Abrysvo...and when. Check your state’s Immunization Information System (IIS) if needed. It syncs with some EHRs automatically.

Be aware that nirsevimab is rarely needed if mom got Abrysvo. But be aware of caveats.

For example, nirsevimab is still recommended if mom got the RSV vaccine off-season...or if the immune response is questionable due to immunocompromise or giving birth less than 14 days after vaccination.

Nirsevimab is also recommended despite vaccination if the baby had cardiopulmonary bypass, which may remove maternal antibodies...or is at high risk of severe RSV due to factors such as congenital heart disease.

Review our resource, Preventing RSV, for more guidance.

Key References

  • Fleming-Dutra KE, Jones JM, Roper LE, et al. Use of the Pfizer Respiratory Syncytial Virus Vaccine During Pregnancy for the Prevention of Respiratory Syncytial Virus-Associated Lower Respiratory Tract Disease in Infants: Recommendations of the Advisory Committee on Immunization Practices - United States, 2023. MMWR Morb Mortal Wkly Rep. 2023 Oct 13;72(41):1115-1122.
  • Kampmann B, Madhi SA, Munjal I, et al. Bivalent Prefusion F Vaccine in Pregnancy to Prevent RSV Illness in Infants. N Engl J Med. 2023 Apr 20;388(16):1451-1464.
  • Jones JM, Fleming-Dutra KE, Prill MM, et al. Use of Nirsevimab for the Prevention of Respiratory Syncytial Virus Disease Among Infants and Young Children: Recommendations of the Advisory Committee on Immunization Practices - United States, 2023. MMWR Morb Mortal Wkly Rep. 2023 Aug 25;72(34):920-925.
  • CDC. Evidence to Recommendations Framework Updates Pfizer Maternal RSVpreF Vaccine. September 22, 2023.
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