Help Sort Out 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.

You’ll get 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 entering their first RSV season...generally October through March.

Clarify that vaccinating pregnant people for RSV generally means the baby will NOT need nirsevimab. Be ready with answers about the options.

Which option is best? It’s too soon to say...there’s no head-to-head data. Reinforce that either vaccination or nirsevimab helps prevent clinic and hospital visits due to RSV in the infant for the season.

Keep in mind, nirsevimab will be the only option for many infants. For example, most babies born April through September will need nirsevimab shortly before RSV season...vaccinating moms off-season isn’t advised.

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

What are the side effects? Abrysvo or nirsevimab are generally well tolerated. Clarify product warnings.

In Abrysvo studies that vaccinated as early as 24 weeks gestation, preterm birth was numerically...but NOT statistically...higher. But 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 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.

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 the RSV vaccine be given at the same time as other vaccines?

Yes, it can be given simultaneously with other vaccines, including flu, COVID-19, and Tdap.

Some data suggest the RSV vaccine might limit the pertussis immune response...but there’s no evidence this decreases effectiveness. If patients are concerned, suggest getting Tdap at 27 to 32 weeks gestation.

Check out 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. (Accessed September 25, 2023).
  • Medication pricing by Elsevier, accessed Oct 2023.
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