Listen for Questions About RSV Prevention in Babies

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

You’ll hear questions about options to prevent respiratory syncytial virus (RSV) in infants.

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 born during or entering their first RSV season.

Know that giving Abrysvo in pregnancy usually means the baby will NOT need nirsevimab. Send patients with questions to your pharmacist.

Which option is most effective?  It’s too soon to say...either helps protect the baby for the RSV season. But there’s no head-to-head data.

Vaccination during pregnancy prevents RSV hospitalization in about 1 in 125 infants. Giving the baby nirsevimab prevents RSV hospitalization in about 1 in 48 infants.

Abrysvo costs $295...nirsevimab is $495. Payers will cover either.

What are the side effects?  Abrysvo or nirsevimab is generally well tolerated.

In studies where Abrysvo was given as early as 24 weeks gestation, preterm birth was numerically...but NOT statistically...higher. FDA approved it to be given LATER in limit this risk.

Nirsevimab labeling warns that serious hypersensitivity reactions or anaphylaxis are with other monoclonal antibodies.

Should nirsevimab ever be given if mom got the RSV vaccine?  Rarely...but there are some 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.

Help communicate administration of the RSV vaccine during pregnancy. For example, document it in your state’s Immunization Information System (IIS) if possible...and suggest that moms include a note on their phone with which vaccines they received during pregnancy.

Can other vaccines be given at the same time as the RSV vaccine?  Yes, especially flu and COVID-19 vaccines.

Some data suggest the RSV vaccine might affect immune response from a Tdap vaccine...but there’s no evidence this decreases effectiveness. If there’s concern, Tdap can be given at 27 to 32 weeks gestation.

Review our resource, Preventing RSV, for more guidance.

Key References

  • 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. Proposed clinical considerations for maternal RSVPreF vaccine and nirsevimab. September 22, 2023. (Accessed September 25, 2023.)
  • Medication pricing by Elsevier, accessed Oct 2023.
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