Nirsevimab Frequently Asked Questions

New FAQ's Added in the Past 30 Days (updated 12/5/2023)

Given the limitations in supply, should we risk stratify beyond what the CDC recommends or is it a first come first serve? 

With the start of the RSV season, which is well underway across the US, we encourage pediatricians to use the doses they have on hand now, and not try to conserve them for later in the season, even if that means making difficult decisions about which patients will be able to receive a dose. We advise pediatricians to assess their patient populations to determine which patients are at highest risk for severe RSV disease. It is important to ensure all infants at highest risk for severe RSV as outlined in the HAN get nirsevimab now.  

For those who are interested in additional guidance, CDC recommends prioritizing 100 mg doses for infants with underlying medical conditions that place them at increased risk of severe disease; American Indian and Alaska Native infants aged <8 months; and all infants <6 months, who have the highest RSV hospitalization rates. For healthcare settings with limited supply of 50 mg doses, pediatricians should assess which patients are at higher risk for severe RSV disease, due to very young age (such as neonates) or due to underlying conditions (such as prematurity), and therefore should be prioritized for nirsevimab. CDC will continue to monitor the situation and provide additional national guidance if needed. 

Should an infant who had a confirmed RSV infection this season still receive nirsevimab?  

When supply is adequate, prior infection should generally not be used to determine an infant’s eligibility for nirsevimab. However, given the current situation of limited supply it is reasonable to defer nirsevimab in infants who have had a documented RSV infection as their risk of severe disease is lower with subsequent RSV infections. With a limited number of doses, we need to prioritize those infants at highest risk of severe RSV. 

What if a young infant is in our office and diagnosed with RSV that day or are within 48 hours of illness onset? Would a dose of nirsevimab be helpful to them to reduce the severity of the illness?  

Nirsevimab has not been studied as a treatment in infants with RSV and is not licensed for treatment of RSV disease. Nirsevimab should be given prior to onset of the RSV season or as soon as possible after birth for infants born during the season to prevent severe RSV disease. 

If a high-risk child mistakenly received a 100 mg dose of nirsevimab when they should have received a 200 mg dose, should we have them return for the other 100mg? 

If a half dose is inadvertently given, another half dose should be administered as soon as possible, but no later than the end of the season (for most of the continental US, this would be through the end of March, unless local guidance is given to administer during a modified time period). This counts as a 200 mg dose.  

Given the limited supply of nirsevimab this season, should more pregnant people receive RSV vaccine? What is AAP doing to promote RSV vaccination during pregnancy?  

Other existing options for protecting infants against RSV are the maternal RSV vaccination and palivizumab for eligible infants and young children. Providers should encourage pregnant people to receive Pfizer’s maternal RSV vaccine (Abrysvo) during 32–36 weeks’ gestation to prevent RSV-associated lower respiratory tract infection, especially in the context of the current nirsevimab supply constraints. This vaccine should be administered during September through January in most of the continental United States. However, in jurisdictions with seasonality that differs from most of the continental United States (e.g., Alaska, jurisdictions with tropical climates), pediatricians should follow state, local, or territorial guidance on timing of administration. The maternal Pfizer vaccine can be simultaneously administered with other indicated vaccinations. 

Similar to nirsevimab, there have been significant implementation challenges with RSV vaccination during pregnancy this season. The AAP collaborated with ACOG and the Society for Maternal-Fetal Medicine on a joint statement on the nirsevimab shortage, which supported RSV vaccination in pregnant people. There are 2 adult RSV vaccines, and only the Pfizer product (Abrysvo) is approved for use in pregnant people. Pfizer has a website to help identify locations that are administering their RSV vaccine.   

How do I order  nirsevimab through Vaccines for Children (VFC)? Will I receive any more doses this season? 

Nirsevimab is being distributed to state immunization programs using an allocation system.  CDC determines allocations based on (1) the total amount of product available and (2) each jurisdiction's ordering history for other routine vaccines used in similar age groups. State immunization programs are then responsible for making decisions about how to direct VFC doses to providers within their jurisdiction, as they are most familiar with the providers, patient populations, and local needs. Additional allocations of 50 mg and 100 mg doses for VFC will be made available to most jurisdictions through the end of December, including additional 50 mg and 100 mg doses. There is a greater quantity of 50 mg doses available this season compared with 100 mg doses. Contact your state immunization program for more details about VFC ordering  and anticipated supply for the 23-24 RSV season.

How do I order commercial/private stock nirsevimab? Will I receive any more doses this season?  

The 100 mg formulation of nirsevimab is unavailable for new orders through Sanofi. Ordering is not anticipated to re-open during the 23-24 RSV season. Sanofi has indicated that they plan to fulfill all orders that have been successfully placed.  

Sanofi re-opened ordering for 50 mg dosage using an allocation system on November 16. 

• Customers should have heard about allocated amounts from their regional rep or via their account on VaccineShop.com. ​
• Customers are able to place a direct order up to their allocation amount for a 30-day period (by December 15).​
• If allocations are not accepted/ordered, Sanofi will offer declined doses to those customers without allocations first.​ 

Within VaccineShop.com customer accounts, customers can click on the "View Details" button to see a "Quantity Limit" pop up window with the following information:

• (A) Total Allocation: shipped units + open orders year to date + units remaining to order
• (B) Units Ordered to Date: shipped units + open orders year to date
• (A-B) Units Remaining: units remaining to order (deadline is 12/15)

For information about ordering from Sanofi, please contact your local Sanofi representative or call 1-855-Beyfortus. 

What should I do if I have borrowed VFC doses that I am unable to pay back due to the limited supply of nirsevimab?  

If you are unable to repay borrowed VFC doses within 30 days, you should contact your state immunization program to discuss.  

About Nirsevimab

Is nirsevimab a vaccine? 

Nirsevimab is a monoclonal antibody product that is a passive immunization. While not technically a “vaccine” in a traditional sense (active immunization), it is being used in a manner similar to routine childhood vaccines and may be referred to as a vaccine by some entities. Nirsevimab confers long-lasting protection from RSV, with protection expected to last at least 5 months (about the length of a typical RSV season). Nirsevimab is part of the Vaccines for Children program.  

Because nirsevimab is a monoclonal antibody product, who can administer it? 

Nirsevimab comes in a prefilled syringe. In most states, anyone who can administer injections can administer nirsevimab.  

How long does the RSV protection conferred by nirsevimab last?  

Protection is expected to last at least 5 months, about the length of an RSV season and is expected reduce the risk of severe RSV disease by about 80%.  

Nirsevimab Ordering and Supply

As VFC providers, can we stock VFC nirsevimab without having private stock? 

According to CDC, VFC providers may be allowed a flexible, time-limited ramp-up period to meet the private inventory requirement for nirsevimab. During this time, awardees will not require VFC providers to meet the private inventory minimum requirements for nirsevimab if they do not intend to vaccinate their private pay patients. VFC providers are required to meet the private inventory requirement no later than August 1, 2024. This may vary by state/jurisdiction.   

Given the current shortage of the 100 mg formulation of nirsevimab, can I administer two 50 mg doses to my patient who is > 5 kg instead?  

Avoid using two 50 mg doses for infants weighing ≥5 kilograms (≥11 pounds), because 50 mg doses should be reserved for smaller infants who are at increased risk for severe RSV illness because of their smaller airways. Furthermore, providers should be aware that insurers may not cover the cost of two 50 mg doses for an individual infant. 

Given the current shortage of nirsevimab, what are some other things I can do to protect my patients? 

Continue to use palivizumab for eligible high-risk children and encourage pregnant people to get vaccinated between 32-36 weeks’ gestation with the RSVpreF vaccine.  

Nirsevimab and Palivizumab

If both nirsevimab and palivizumab are available for high-risk patients (including those born at < 29 weeks gestational age), which should they receive?  

 If nirsevimab supply is inadequate, CDC recommends that providers suspend using nirsevimab in palivizumab-eligible children aged 8–19 months for the 2023–2024 RSV season. These children should receive palivizumab per American Academy of Pediatrics (AAP) recommendations. Nirsevimab should continue to be offered to American Indian and Alaska Native children aged 8–19 months who are not palivizumab-eligible and who live in remote regions, where transporting children with severe RSV for escalation of medical care is more challenging or in communities with known high rates of RSV among older infants and toddlers. 

Nirsevimab Administration, Side Effects/Contradindications, and Timing

Can nirsevimab be co-administered with other routine vaccines?  

Yes. In accordance with CDC General Best Practices for Immunizations, simultaneous administration of nirsevimab with age-appropriate vaccines is recommended. Nirsevimab is not expected to interfere with the immune response to other vaccines and had similar safety and reactogenicity profiles to vaccines administered without nirsevimab.  

Are there maximum volumes of injectable vaccine, antibiotic or other products that can be administered into each muscle group for different ages? For example, at the 6-month well-child visit, could an infant receive nirsevimab, Covid-19, influenza, PCV, and DTaP-IPV-hepB-Hib? 

In accordance with the CDC’s General Best Practice Guidelines for Immunization, simultaneous administration of nirsevimab with age-appropriate vaccines is recommended.  CDC does not address the issue of maximum volumes that can be injected into each muscle group in different age groups.  CDC is in the process of creating a job aid for healthcare providers to help address the issue and offers the suggested volumes as follows: 

• Deltoid:
• Average 0.5 mL (range 0.5–2 mL)
• Vastus Lateralis:
• Average 1–4 mL (range 1–5 mL) 

Infants and toddlers would fall at the lower end of the range, whereas adolescents and adults would generally fall on the higher end of the range. Strategies healthcare providers can use to decrease the number/injection volume include:  

1. Healthcare providers should always use professional judgement when administering injections. Muscle size can vary greatly from one patient to another. 
2. Include an age-appropriate combination vaccine in the facility’s inventory (Pentacel, Pediarix, Vaxellis). 
3. Use an alternate route (other than IM) if possible.  IPV (single component, NOT a combination vaccine), MMR (toddlers and infant travelers only), Varicella-containing vaccines (toddlers only), and PPSV23 (high-risk toddlers only) can be administered subcutaneously. 
4. Take advantage of recommended age ranges some of the routinely recommended vaccines have.  For example, the 3rd dose of HepB can be given as late as 18 months of age. 

What are the potential side effects of nirsevimab?  

CDC recently published an Immunization Information Statement (VIS-like document) for families. It states that “After getting an RSV preventive antibody, your child might have temporary pain, redness, swelling where the injection was given, or a rash.”  In addition, the nirsevimab package insert has additional information on adverse reactions. “Most common adverse reactions were rash (0.9%) and injection site reactions (0.3%).” 

Are there any contraindications to receiving nirsevimab? Can an infant or young child receive nirsevimab when they are sick?  

Nirsevimab is contraindicated in infants and young children with a history of serious hypersensitivity reactions, including anaphylaxis, to nirsevimab or to any of its components. Illness or febrile diseases are not contraindications to receiving nirsevimab. The AAP suggests following CDC General Best Practice Guidelines for Immunizations, which recommends that vaccination should be deferred for persons with a moderate or severe acute illness, as this precaution avoids causing diagnostic confusion between the underlying illness and potential adverse effects of immunization. Similar to routine childhood vaccines, mild illness – with or without fever – should not be used as a reason to delay administration of nirsevimab.   

What does "shortly before or during” the RSV season mean?  When should I start administering nirsevimab? 

In most of the continental US, “shortly before or during the season” means that administration of nirsevimab should begin on October 1 and conclude on March 31. In tropical climates (southern Florida, Hawaii, Guam, Puerto Rico, US Virgin Islands and US-affiliated Pacific Islands) and Alaska, RSV circulation patterns may differ. Because timing of the onset, peak and decline of RSV activity may vary, providers can adjust administration schedules based on local RSV activity in the community.  The Centers for Disease Control and Prevention (CDC) monitors RSV activity in the United States in collaboration with state and county health departments and commercial and clinical laboratories. These data are available from the National Respiratory and Enteric Virus Surveillance System. Information about local epidemiology can be determined by contacting your local, state, tribal, or territorial health department or other local health authority. Optimal timing for nirsevimab administration is shortly before the RSV season begins, however, it may be given to eligible infants and toddlers who have not yet received a dose at any time during the season.  

Per CDC, healthcare providers may choose to give nirsevimab before the start of RSV season if they feel that the child may not return for a visit when nirsevimab would be recommended. For example, a clinician may choose to give nirsevimab to an infant who presented for care in September who has not yet received a dose of nirsevimab and may be unlikely to return for a visit in October or November. Nirsevimab has been shown to protect against severe RSV disease for at least 5 months, and the ideal timing of administration may differ depending on the clinical situation. 

Who Should Receive Nirsevimab?

Should I administer nirsevimab to an infant who is born at the very end of the RSV season?  

Yes. Optimal timing for administration is within 1 week after birth during the RSV season. Administering nirsevimab through the end of the season is important because the risk of severe disease is highest during the first few months of life. 

If an infant’s mother has received maternal RSV vaccine, should the infant receive nirsevimab?  

Maternal RSV vaccine was approved by the FDA on August 21, 2023. The CDC does not recommend nirsevimab for most infants born to a mother who received maternal RSV vaccine, except for infants where less than 14 days have elapsed between vaccination and birth.    

Nirsevimab can be considered for infants born to a mother who received maternal RSV vaccine when, per the clinical judgement of the healthcare provider, the potential incremental benefit of administration is warranted, including but not limited to the following rare circumstances: 

Infants born to pregnant people who may not mount an adequate immune response to vaccination or have conditions associated with reduced transplacental antibody transfer 

Infants who have undergone cardiopulmonary bypass or extracorporeal membrane oxygenation leading to loss of maternal antibodies 

 Infants with substantial increased risk for severe RSV disease (eg, hemodynamically significant congenital heart disease, intensive care admission and requiring oxygen at discharge) 

I have a healthy patient who was 7 months old in October. They present to the clinic in November, at 8 months of age. Can they receive nirsevimab at this visit?  

No. CDC recommends that only those healthy infants younger than 8 months of age at the time of administration receive nirsevimab.  In situations of limited availability of nirsevimab, CDC currently recommends prioritizing infants aged < 6 months. 

Can a baby who is 9 months old but corrects to 6.5 months due to prematurity (delivery at 29 weeks gestational age) receive nirsevimab? 

In accordance with CDC General Best Practice Guidelines for Immunization preterm infants (infants born before 37 weeks’ gestation), regardless of birth weight, should receive nirsevimab at their chronological age using the same guidance for full-term infants and young children.  

Will infants born during the RSV season receive nirsevimab before they are discharged from the hospital? 

It is recommended that infants born shortly before and during the RSV season receive nirsevimab within the first week of life, including in hospital settings. Infants with prolonged birth hospitalizations because of prematurity or other causes should receive nirsevimab shortly before or promptly after discharge. During the 23-24 RSV season, if a hospital has been unable to implement administration of nirsevimab, the infant should receive nirsevimab in an ambulatory setting as soon as available. Currently, few hospitals participate in the VFC program, and additional advocacy to support hospital participation is ongoing. Timely and well-coordinated communication between birth hospital and the medical home is important. Equitable access to nirsevimab will require those in a community to work together.  

Which children should receive a dose of nirsevimab in their second RSV season?  

In the context of limited supply of nirsevimab during the 2023-2024 season, CDC recommends suspending use of nirsevimab in palivizumab-eligible children aged 8-19 months, except for American Indian and Alaska Native children aged 8–19 months who are not palivizumab-eligible and who live in remote regions, where transporting children with severe RSV for escalation of medical care may be challenging, or in communities with known high rates of severe RSV among older infants and toddlers. 

If a patient was born towards the end of March and did not receive nirsevimab, can they receive nirsevimab in October?  

Yes. Per AAP’s guidance, healthy infants born at the end of their first RSV season who did NOT receive nirsevimab and are <8 months of age entering their second RSV season may receive one dose of nirsevimab. In the context of limited supply during the 2023-2024 RSV season, CDC recommends prioritizing available nirsevimab 100mg doses for infants at the highest risk for severe RSV disease: young infants (age <6 months) and infants with underlying conditions that place them at highest risk for severe RSV disease.  

Why are infants 8-12 months old ineligible to receive nirsevimab (unless they are considered high-risk)?  

The highest risk for severe RSV is in children under 6 months of age.  Infants 8 months and older will be entering their second RSV season and have likely already experienced their first RSV infection and will not receive the full benefits of nirsevimab.   

Should American Indian and Alaska Native infants and young children from birth – 19 months of age receive palivizumab if nirsevimab is unavailable?  

If nirsevimab is unavailable, only those high-risk American Indian and Alaska Native infants and young children who meet current criteria for palivizumab should receive it. American Indian or Alaska Native heritage is not an indication for first or second season palivizumab. 

What is the guidance for high risk infants who are 19-24 months of age, particularly given nirsevimab has been FDA approved for infants and toddlers 24 months of age and younger who are at high risk for severe RSV illness?  

A dose of nirsevimab is recommended for some children aged 8 through 19 months who are at increased risk for severe RSV and who are entering their second RSV season (note this is inclusive of 19 months). Nirsevimab provides at least 5 months of protection and should be offered to eligible children when entering the RSV season. 

Nirsevimab is not recommended for any child who is age 20 months and older. Children ages 20 months and older have likely already experienced two RSV seasons and been infected with RSV, and thus are less likely to benefit from nirsevimab.  

Coding and Payment

Is nirsevimab financially feasible for my practice? What flexibilities are available when I implement nirsevimab in my practice? 

• Payment terms for this season for those ordering direct from Sanofi are 150 days from time of shipment.
• There is no minimum order size. Nirsevimab is packaged as five single dose prefilled syringes per carton in both formulations.
• Nirsevimab is fully returnable upon expiration. Sanofi offers credit (credit based on exact amount returned and the invoice purchase price that is net of prompt pay or other discount(s)) upon expiration on all full and open box Sanofi product(s) directly purchased from Sanofi that are returned within 1 year after the expiration date.  

How do I code and bill for nirsevimab? Will I be paid appropriately? 

See current coding and billing recommendations, including Coding Vignettes, on the nirsevimab Coding and Payment page.  

Does nirsevimab require insurance prior authorization, as palivizumab does?   

No, nirsevimab does not require insurance preauthorization.  

Reporting

If a patient has an adverse reaction to nirsevimab, where should it be reported? 

Adverse events when giving nirsevimab alone should be reported to the  FDA’s MedWatch Adverse Event Reporting Program.  

If an adverse event occurs while co-administering nirsevimab with a vaccine, it should be reported to the Vaccine Adverse Event Reporting System.  

Do I need to report nirsevimab administration to my state immunization information system (IIS)? 

Yes. You should report nirsevimab administration to the state IIS in accordance with state policies for reporting of vaccine administration.  

Talking to Families

Will there be a Vaccine Information Statement (VIS) available for nirsevimab?  

CDC has developed a “VIS-like” document – called an Immunization Information Sheet on nirsevimab. You are encouraged to share this document with parents/families when administering nirsevimab. You can download a copy on the CDC site.   

What resources are available for talking to families about RSV immunization?   

Please visit www.healthychildren.org/rsv for resources on talking about RSV immunization with families.  In addition, AAP has a patient brochure on RSV that is available in various languages.  

How can families prevent RSV infection?  

Families should take preventative measures to stop the spread of RSV and other respiratory illnesses, including washing hands, covering coughs and sneezes, cleaning frequently touched surfaces, and staying home when sick. 

Expectant parents should talk with their healthcare provider about receiving the RSV vaccine (Abrysvo, Pfizer) during pregnancy to protect their infant from severe RSV. CDC recommends that all infants are protected against RSV through either vaccination of the mother with RSV vaccine during pregnancy or giving the infant nirsevimab after birth. 

Parents should talk with their healthcare provider about whether nirsevimab is available for their infant.