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RSV Frequently Asked Questions (FAQs)

This webpage is designed to help providers and local health department staff stay abreast on the latest information on RSV immunizations.

What is RSV?
Respiratory syncytial virus, or RSV, is a common respiratory virus that usually causes colds, but may cause severe disease in infants and older adults. In the United States, RSV usually starts in the fall season and peaks in the winter.

RSV is the leading cause of hospitalization and the most common cause of bronchiolitis and pneumonia in children younger than 1 year of age in the United States. Almost all children get RSV at least once before they are two years of age. 

In adults, the risk of severe RSV illness also increases with age. Infections are especially dangerous for older adults or those with underlying medical conditions. Each year an estimated 60,000-160,000 older adults are hospitalized and up to 10,000 die due to RSV.

When should RSV immunizations be given?
Please refer to the image below for recommended immunization timing based on the patient. See other FAQs for additional information. 

(PDF version of image above)

Jump to RSV immunization information for:


RSV Vaccines (Abrysvo, Arexvy, and mRESVIA) for Adults  

  1. Who should receive the RSV vaccine for adults?
    Adults 75 years and older and adults 60-74 years who are at increased risk of severe RSV disease should receive a single dose of RSV vaccine. Persons who have already received RSV vaccination are NOT recommended to receive another dose. RSV vaccines may be administered year-round to adults, CDC encourages providers to maximize benefits of adult RSV vaccination by offering in the late summer or early fall.                                                                  
  2. How many doses of RSV vaccine do I give and how long does RSV vaccine provide protection?                                                                        One dose of RSV vaccine is recommended at this time. So far, RSV vaccines appear to provide some protection for at least two RSV seasons. Additional surveillance and evaluation activities are planned to assess how long the vaccines protect against RSV and whether additional doses will be needed.              
  3. Can you administer the RSV vaccine with other vaccines recommended for adults?
    Yes! It is safe to administer RSV vaccine with other recommended vaccines, including influenza and COVID-19 vaccines.
  4. Is RSV vaccine covered by Medicare and private insurance?
    The RSV vaccine is covered by Medicare Part D only (NOT Part B). The Affordable Care Act (ACA) typically requires coverage for all immunizations administered within the year after the ACIP recommendation. Starting January 2023, Part D plans may not apply a deductible or other enrollee cost-sharing requirement for ACIP-recommended vaccines. Individuals, or their healthcare providers, should contact their health insurance plan to see if and when the immunization is covered along with reimbursement requirements.
  5. Is RSV vaccine available through the Vaccines for Adults (VFA) Program for uninsured or underinsured adults?
    Yes, however available quantities are limited. Please check with VFA for updates. You can contact the VFA program at
  6. Am I able to record doses of RSV vaccines (Abrysvo and Arexvy) in CAIR now?
    Yes! You can record doses administered of Abrysvo and Arexvy in CAIR now.  Doses are valid when administered to persons 60 years of age or older.  Per California law, please ensure all vaccines administered are entered into the Immunization Registry (CAIR or RIDE).
  7. Is V-safe available for RSV vaccine?
    Yes, v-safe is available for RSV vaccines. V-safe is a safety monitoring system that lets your patients share with CDC how they, or their dependent, feels after getting an RSV vaccine. Patients can register at CDC’s V-safe website.


Beyfortus (Nirsevimab): RSV Immunization (Monoclonal Antibody) for Infants

  1. When should infants receive Beyfortus (Nirsevimab)?

    ACIP recommends Beyfortus (Nirsevimab) for two different age groups:

    • All infants less than 8 months born during or entering their first RSV season should receive one dose of nirsevimab (50mg for infants <5kg or 100mg for infants >5kg).
    • Infants and toddlers 8-19 months who are at increased risk of severe RSV disease and entering their second RSV season should receive a 200 mg dose of nirsevimab.

    For additional details, please refer to the Nirsevimab (Beyfortus) Guide to Prevent Severe RSV in Infants and Toddlers.

  2. At what age should infants receive Beyfortus (Nirsevimab)?

    Generally, RSV season starts in October and ends in March. Infants born during the RSV season should get one dose of nirsevimab as soon as possible after birth. Infants younger than 8 months of age born in the months outside of the RSV season should get immunized in October or November.

    (Please note: The older monoclonal antibody Palivizumab has previously been recommended for children under 24 months of age with certain conditions that place them at high risk for severe RSV disease. It is given once a month during RSV season. Palivizumab should continue to be used if nirsevimab is not available at the recommended time).

  3. How long does Beyfortus (Nirsevimab) provide protection?
    One dose should protect for at least 5 months (the length of an average RSV season). See CDC RSV Health Advisory for more information.
  4. How effective is Beyfortus (Nirsevimab) immunization in infants?
    An early estimate based on data collected between October 2023 – February 2024 from infants <8 months of age suggests that nirsevimab is 90% effective in keeping immunized infants from being hospitalized with RSV-associated infection in the first months after administration. 
  5. If a patient <5kg comes to an ambulatory clinic and only the 100mg dose version of nirsevimab is available, can half the syringe be given to this patient?
    No. Nirsevimab is supplied as a prefilled syringe in 50 or 100 mg doses. For children weighing <5 kg, an appropriate 50mg dose using the 50 mg prefilled syringe should be used for this patient, as per the manufacturer’s instructions in the package insert: label ( Splitting prefilled syringes into multiple doses could lead to potential risk of dosing errors, dose wastage, or contamination of the prefilled syringe, and thus should not be done.
  6. If a patient comes to an ambulatory clinic and the 100mg dose version of nirsevimab is not available, can two 50mg syringes be given?
    In the context of the 2023-2024 season and nirsevimab shortage, CDC recommends avoiding using two 50mg doses for infants weighing ≥5 kilograms (≥11 pounds), because 50mg doses should be reserved only for infants weighing <5 kilograms (<11 pounds), for example those born during the season who will be at increased risk for severe RSV illness because of their young age. Furthermore, providers should be aware that some insurers may not cover the cost of two 50mg doses for an individual infant.
  7. Can you administer Beyfortus (Nirsevimab) with other vaccines recommended for infants and young children?
    Yes! It is safe to administer the RSV immunization at the same time as other recommended immunizations for children, including influenza and updated COVID-19 vaccines.
  8. Will private insurance cover Beyfortus (Nirsevimab) for infants?
    The Affordable Care Act (ACA) typically requires coverage for all immunizations administered in accordance with ACIP recommendations. Individuals, or their healthcare providers, should contact their health insurance plan to see if and when nirsevimab is covered along with reimbursement requirements.
  9. Is Beyfortus (Nirsevimab) available through the Vaccines for Children (VFC) Program? 
    Yes. Beyfortus (Nirsevimab) is now available through the VFC Program.
  10. Are VFC providers required to offer Beyfortus (Nirsevimab)?
    Yes. VFC providers are required to offer nirsevimab if they see patients in that age group, along with all other age-appropriate ACIP-recommended vaccines. See VFC’s provider requirements for more detail.
  11. How can I become a VFC Program provider if not already?
    ​If you would like to enroll in the VFC program, please visit the VFC Enrollment page to submit an enrollment application or call the VFC Program Customer Service Center at (877) 243-8832.
  12. Please describe protection from Beyfortus (Nirsevimab) in simpler language for parents.
    Immunity from antibodies can either be received from another source or produced inside in reaction to a vaccine.The antibodies in nirsevimab are similar to those that babies would:

    • develop after a typical vaccine or
    • receive before birth if mom was vaccinated during pregnancy.

  13. Which provider types may administer Beyfortus (Nirsevimab)? 
    Providers that may administer nirsevimab include physicians, physician assistants, nurses, medical assistants, pharmacists and pharmacy interns, assuming that they meet their usual conditions for immunizing
  14. Am I able to record doses of Beyfortus (Nirsevimab) for infants in CAIR now?
    Yes! Beyfortus (Nirsevimab) is in CAIR now under the brand name “Beyfortus.”
  15. Am I required to record doses of Beyfortus (Nirsevimab) for infants in CAIR?
    Yes, it is a requirement. Per California law, please ensure all immunizations administered are entered into the Immunization Registry (CAIR or RIDE).
  16. Where can I find the latest CDC guidance on the use of nirsevimab?
    As of January 2024, nirsevimab supply has increased, and CDC advises healthcare providers to return to recommendations put forward by CDC and the Advisory Committee on Immunization Practices (ACIP) on use of nirsevimab in young children. Infants and children recommended to receive nirsevimab should be immunized as quickly as possible. For more information, refer to CDC guidance and this CDPH job aid.
  17. How can I talk to parents about the nirsevimab shortage?
    • Empathize with them in their desire to protect their baby from severe RSV. Explain that there is currently a shortage of Nirsevimab across the US.  While CDC continues to work with the manufacturer to increase supplies, it is not clear when the shortage will end.
    • CDPH anticipates that more supplies will be arrive at doctors’ offices over the fall and winter, but we don’t know how much or how soon.  Please reassure families that once supplies are available, you will reach out to them right away.
  18. Where should I report adverse events following nirsevimab administration?
    • If nirsevimab is administered alone, report side effects to the MedWatch website online, by fax, by mail or by calling 1-800-FDA-1088.
    • If nirsevimab is administered with any vaccine on the same day, report side effects to the Vaccine Adverse Event Reporting System (VAERS). Reports should specify that the patient received nirsevimab on the VAERS form in Section 9: “Prescriptions, over-the-counter medications, dietary supplements, or herbal remedies being taken at the time of vaccination.” Reports can be submitted to VAERS online, by fax, or by mail. Additional information about VAERS is available by telephone (1-800-822- 7967) or online. When adverse reactions that occur after the coadministration of nirsevimab with a vaccine are reported to VAERS, additional reporting of the same adverse reactions to MedWatch is not necessary.


RSV Vaccine for Pregnant People

  1. What is the RSV vaccine recommendation for pregnant people?
    CDC recommends RSV vaccine, Abrysvo, for all pregnant people at 32 through 36 weeks gestation, using seasonal administration (September—January), to prevent RSV-associated lower respiratory tract infection in infants. Abrysvo is the only RSV vaccine approved for pregnant persons. Arexvy and mRESVIA are NOT approved for pregnant persons.                                                                                                                                                                       
  2. When is prenatal immunization against RSV recommended to be given?

    CDC recommends that immunization against RSV (with Abrysvo) be administered to all pregnant persons at 32-36 weeks gestation from September through the end of January. The benefits and cost-effectiveness of prenatal immunization against RSV are expected to diminish in most of the US during February and later months. Check with insurers regarding reimbursement for any administration after January.                                           For people who previously received the maternal RSV vaccine (Abrysvo), during future pregnancies they are NOT recommended to receive additional vaccine doses and their infants should receive nirsevimab. 


    As an alternative, administration to infants after birth of the remaining doses of nirsevimab is recommended by CDC in most of the US through the end of March – Please continue to administer your remaining doses of nirsevimab to protect infants and toddlers against RSV if prenatal immunization was not given.                                                                                                                                                                                                                 Please note that: Both RSV vaccine and nirsevimab have a lengthy shelf life and are expensive. Save unused doses for Fall 2024 and consider labeling as “Keep for Fall 2024.” Unused and unexpired doses of VFC RSV vaccines cannot be returned to McKesson. Privately purchased doses of ABRYSVO may continue to be used year-round to protect patients 60 years and older (while VFC supplies are indicated for pregnant adolescents). 

  3. Are infants recommended to receive Beyfortus (Nirsevimab) if their birthing parent was immunized during pregnancy?                             Most infants will likely only need protection from either the prenatal RSV vaccine or infant immunization, but not both. Infants <8 months entering their first RSV season should receive RSV immunization if their birth parent’s prenatal RSV vaccination status is: unvaccinated, unknown or vaccinated <14 days before birth. In some limited cases, an infant may be eligible to receive both immunizations.                                                                                            

  4. How long does protection from prenatal RSV vaccine last?
    In the clinical trials for the RSV vaccine given during pregnancy, infants through 6 months of age were protected against RSV-associated lower respiratory tract infection. The clinical trials did not measure protection beyond 6 months of age.
  5. Can prenatal RSV vaccine be co-administered with other prenatal vaccines such as Tdap, flu and COVID-19 vaccines?
    Yes. You can receive the RSV vaccine on the same day as other vaccines recommended during pregnancy, including Tdap, COVID-19, and influenza.
  6. What is safety profile of prenatal RSV vaccine?
    In the clinical trials, the side effects most often reported by pregnant people who received prenatal RSV vaccine were pain at the injection site, headache, muscle pain, and nausea.The clinical trials identified a small increase in the numbers of vaccinated pregnant people with preterm births or very high blood pressure. It is not clear if this was a chance finding or somehow related to RSV vaccine. To mitigate this theoretical risk, prenatal RSV vaccine is indicated in the late trimester at 32 to 26 weeks gestation. CDC and FDA are continuing to monitor the safety of prenatal RSV vaccine. 

  7. Is the prenatal RSV vaccine covered by Medi-Cal and private insurance?
    The Affordable Care Act (ACA) typically requires coverage for all immunizations administered within the year after the ACIP recommendation. Medi-Cal also offers immunizations as a medical and pharmacy benefit. Prenatal care providers who do not stock prenatal immunizations should provide strong referrals to patients’ in-network pharmacies. Individuals, or their healthcare providers, should contact their health insurance plan to see if and when the immunization is covered along with reimbursement requirements.
  8. How can a provider evaluating a baby for Beyfortus (Nirsevimab) determine if the baby’s birthing parent received prenatal RSV vaccine?
    If prenatal records are unavailable to determine if the baby’s birthing parent was immunized during pregnancy, the birthing parent may request an immunization history report from their prenatal care provider or access their Digital Vaccine Record at immunizing provider may also check the California Immunization Registry (CAIR) to confirm receipt of prenatal RSV vaccine at least 14 days before delivery or postnatal nirsevimab at the birth hospital or clinic.
  9. How should prenatal RSV vaccination be documented?

    It is critically important to document receipt of maternal RSV vaccine as most infants of vaccinated mothers are not recommended to receive nirsevimab. Documentation should occur in the:

    • Immunization Information System (CAIR or Healthy Futures)
    • Electronic Health Records (EHRs)
    • Written documentation for patient to bring to birthing hospital and pediatric provider visits.

  10. Is V-safe available for RSV vaccine given to pregnant people?
    Yes! V-safe is now available for RSV vaccines given to pregnant people. V-safe is a safety monitoring system that lets you share with CDC how they, or their dependent, feels after getting an RSV vaccine. Patients can register at CDC’s V-safe website.
  11. If a pregnant person received RSV vaccine before 32 weeks of pregnancy, should they get another dose of RSV vaccine between 32 to 36 weeks and should their infant receive nirsevimab?

For doses given before 24 weeks gestation:

  • Do not repeat the dose
  • For RSV prevention, the infant should receive nirsevimab shortly before or during the first RSV season (at age <8 months).

For doses given during 24 weeks and 0 days’ and 31 weeks and 6 day’s gestation:

  • Do not repeat the dose
  • All infants born <34 weeks’ gestation should receive nirsevimab.
  • Infants born after 34 weeks do not need nirsevimab. This is based on data from the Pfizer phase 3 trial, in which efficacy was assessed among participants who received vaccination during 24 through 36 weeks gestation

For additional information, please see RSV Resources.


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