Ask the Experts: RSV (Respiratory Syncytial Virus): RSV Preventive Antibody Administration

Results (7)

Nirsevimab (Beyfortus, Sanofi) dosing is based upon weight and/or age. It is available in 50-mg or 100-mg manufacturer-filled syringes (MFS). Infants younger than 8 months and weighing less than 5 kgs (11 lbs.) should receive a 50-mg dose, given as a 50-mg MFS. Infants younger than 8 months and weighing 5 kg (11 lb.), or more, should receive a single 100-mg dose, given as a 100-mg MFS. Infants and toddlers age 8 months through 19 months who need nirsevimab should receive a 200-mg dose, given as two 100-mg MFS.

Do not administer two 50-mg MFS to an infant who needs a 100-mg MFS. The supply of 50-mg MFS is intended for the smallest infants. The cost of the 50-mg and 100-mg MFS are equivalent, despite the difference in dose; insurance plans may not cover the cost of two doses given to an infant not recommended to receive two doses. Only high-risk children age 8 through 19 months are recommended to receive two (100-mg) MFS doses at the same visit.

See the Immunize.org standing order template for details: www.immunize.org/wp-content/uploads/catg.d/p3097.pdf.

Last reviewed: August 25, 2024

The supply of 50-mg manufacturer-filled syringes (MFS) of nirsevimab (Beyfortus) should be reserved for infants weighing less than 5 kilograms (less than 11 pounds). In addition, insurers may not cover the cost of two 50-mg MFS doses administered to one infant. The cost of a single MFS is the same, whether it is a 50-mg MFS or a 100-mg MFS. Only high-risk children age 8 through 19 months are recommended to receive two (100-mg) MFS doses at the same visit.

Last reviewed: August 25, 2024

Yes, nirsevimab (Beyfortus, Sanofi) may be coadministered with all other recommended age-appropriate vaccines. Nirsevimab should not interfere with the immune response to routine childhood vaccines when given together or at any time before or after them. Likewise, vaccination does not interfere with the effectiveness of nirsevimab.

When giving several injections at a single visit, separate intramuscular vaccines by at least 1 inch in the body of the muscle, if possible, to reduce the likelihood of overlapping local injection site reactions.

Last reviewed: August 25, 2024

No, these two antibody preparations should not interfere with each other. Administer nirsevimab (Beyfortus, Sanofi) as recommended.

Last reviewed: August 25, 2024

Nirsevimab (Beyfortus, Sanofi) comes in a prefilled syringe. In most states, anyone who can administer injections can administer nirsevimab. If you have questions about a specific type of healthcare worker, check the scope of practice rules in your state.

Last reviewed: August 25, 2024

Only infants younger than age 8 months 0 days are routinely recommended to receive nirsevimab (Beyfortus, Sanofi) during or before their first RSV season. The recommended use of nirsevimab in older infants and toddlers age 8 months through 19 months is narrowly limited to American Indian/Alaska Native children and children with specific conditions that put them at high risk of severe lower respiratory tract disease due to RSV.

Last reviewed: August 25, 2024

The recipient should be informed of the error, and RSV vaccine should be administered as recommended. A 50-mg or 100-mg MFS dose of antibody is very small compared to the body weight of an adult and you should not assume the dose would have any protective effect. There is no defined waiting period after antibody administration for vaccine administration. Facilities that stock RSV vaccine and nirsevimab (Beyfortus, Sanofi) should put systems and procedures in place to prevent this type of error, including staff training and clear labeling and warnings in storage units.

CDC strongly encourages reporting of this medication error and any suspected adverse events following the error to the Vaccine Adverse Event Reporting System (VAERS) at https://vaers.hhs.gov if the antibody was administered at the same visit as vaccines. If antibody was administered alone, report the incident to MedWatch online (www.fda.gov/medwatch), by fax, by mail, or by contacting FDA at 1-800-FDA-1088.

Last reviewed: August 25, 2024

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