RSV Immunization Administration Frequently Asked Questions

RSV Immunization Ordering and Supply

Given nirsevimab has a shelf life of about 24 months and clesrovimab has a shelf life of about 30 months, should I purchase extra doses to have on hand knowing I can always use them next season?

It is noted that data does not currently exist about the impact of temperature excursions on nirsevimab or clesrovimab; if temperature excursions occur, you will likely be advised to discard the product, which could have financial implications. Choices about quantities of product to purchase are individual, by practice or institution.

Can I administer two 50 mg doses of nirsevimab to my patient who is > 5 kg instead of a 100 mg dose?

Avoid using two 50 mg nirsevimab 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 nirsevimab doses for an individual infant.

Can we split a 100 mg manufacturer-filled syringe (MFS) of nirsevimab into two 50 mg doses?

No, nirsevimab 100 mg doses are approved for single use.  
 
Manufacturer-filled syringes are prepared with a single dose and sealed under sterile conditions by the manufactures. They do not contain a preservative to help prevent the growth of microorganisms.  
 
They are intended for ONE patient for ONE injection. Never administer medications from the same syringe to more than one patient, even if the needle is changed.  
 
Attempting to split 100 mg MFS into two 50 mg doses is a serious administration error that risks inadvertent contamination and infection transmission.

Palivizumab

If an infant received palivizumab in season 1, can they receive nirsevimab or clesrovimab?

If palivizumab was administered in season 1 and the child is eligible for RSV prophylaxis in season 2, the child should receive nirsevimab in season 2.

Is palivizumab recommended?

No, palivizumab is no longer routinely recommended for use by the AAP and it will be discontinued as of December 31, 2025.

RSV Immunization Administration, Side Effects/Contraindications, and Timing

Because nirsevimab and clesrovimab are monoclonal antibody products, who can administer them?

Nirsevimab and clesrovimab come in prefilled syringes. In most states, anyone who can administer injections can administer nirsevimab and clesrovimab.

Can RSV immunization be co-administered with other routine vaccines?

Yes. In accordance with Immunize.org guidance, simultaneous administration of RSV immunization with age-appropriate vaccines is recommended. Nirsevimab and clesrovimab are not expected to interfere with the immune response to other vaccines and had similar safety and reactogenicity profiles to vaccines administered without nirsevimab or clesrovimab.

The current recommendation is that if an infant’s pregnant parent received RSV vaccine < 14 days prior to the infant’s birth, the infant should receive RSV immunization. In this scenario, is there a minimum interval between RSV vaccine (Abrysvo) administration in the pregnant parent and administration of RSV immunization (ie. nirsevimab or clesrovimab) in the infant? 

No, there is no minimum interval.

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.

How can pediatricians minimize the likelihood of immunization errors?

Vaccine providers who carry both infant RSV immunizations and RSV vaccine products for adults should be especially diligent in following vaccine administration safety procedures to prevent errors. To minimize risk of errors:

• Store nirsevimab/clesrovimab and RSV vaccine in their original packaging on different shelves and clearly label the shelves.
• Educate staff about the differences in indication including age for use, preparation, and dosage.
• Confirm with the patient or caregiver the product(s) they are expecting to receive.

RSV Immunization Recommendations

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 RSV immunization at this visit?

No. CDC recommends that only those healthy infants younger than 8 months of age at the time of administration receive RSV immunization.

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

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

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

It is recommended that infants born shortly before and during the RSV season receive RSV immunization within the first week of life, including in hospital settings. If a hospital has been unable to implement administration of nirsevimab or clesrovimab, the infant should receive RSV immunization in an ambulatory setting as soon as available. Not all 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 RSV immunization will require those in a community to work together.

Infants with prolonged birth hospitalizations because of prematurity or other causes should receive RSV immunization shortly before or promptly after discharge. Health care–associated RSV disease occurs; however, the incidence is unknown. Standard and contact infection control practices are indicated to decrease health care–associated RSV disease. Safety data for use of RSV antibody in infants with a postmenstrual age (gestational age at birth plus chronologic age) of < 32 weeks or who weigh < 3.5 lb (<1.6 kg) are limited.  To prevent health care–associated RSV disease, providers may consider administering RSV immunization to eligible hospitalized infants during their hospitalization. This decision should be based on clinical judgment, considering the potential risks and benefits, as well as local RSV activity. For more information, see http://dx.doi.org/10.15585/mmwr.mm7432a3.

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

Yes. Per AAP’s guidance, healthy infants born at the end of their first RSV season who did NOT receive RSV immunization (and whose birthing parent did not receive RSV vaccine during pregnancy) may receive one dose of RSV immunization if they are < 8 months of age entering their second RSV season.

If a standard risk patient was born last March and received RSV immunization and will be < 8 months of age in October, can they receive another dose of RSV immunization? What about if this standard risk patient’s pregnant parent received Abrysvo > 14 days prior to their birth last March? Can they receive a dose of RSV immunization this season?

No. In both scenarios, the infant is not eligible to receive RSV immunization since it is their second RSV season. Only children who meet high-risk criteria should receive RSV immunization in their second RSV season. For more details on high-risk criteria, please see the full AAP recommendations here.

Why are the high-risk criteria for second season RSV immunization administration limited to 4 groups?

Leading up to licensure and recommendations for nirsevimab, an extensive review of risks for severe RSV in the second season was reviewed in detail by the CDC’s RSV ACIP Working Group and AAP Committee on Infectious Diseases. Those data led to agreement by the ACIP Working Group, the AAP and the full ACIP panel, that the four groups chosen were the optimal groups for second season recommendations. 

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. Clesrovimab is not recommended for any child who is age 8 months and older.

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 RSV immunization be helpful to them to reduce the severity of the illness?

Nirsevimab and clesrovimab have not been studied as a treatment in infants with RSV and is not licensed for treatment of RSV disease. RSV immunization 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.

Coding and Payment

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

• There is no minimum order size. Nirsevimab is packaged as five single dose prefilled syringes per carton in both formulations. Clesrovimab is packaged as either one single dose prefilled syringe or ten single dose prefilled syringes. 
• 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 RSV immunization? Will I be paid appropriately?

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

Does RSV immunization require insurance prior authorization?  

In most instances, RSV immunization does not require insurance preauthorization. Please report any payer concerns or hassles to the Coding & Payment Hotline.