II. Indications
- RSV Prophylaxis in all children age <8 months in their first RSV season (typically October to March in U.S.)
- Not needed if mother received RSV Vaccine at least 2 weeks prior to delivery (during RSV season)
- High risk infants (e.g. Congenital Heart Disease) should receive Nirsevimab regardless of maternal RSV Vaccine
- RSV Prophylaxis in all children age 8 to 19 months in their second RSV season who are at risk for severe disease
- Single dose alternative to Palivizumab
- See Palivizumab for high risk indications
- High risk infants may be given Nirsevimab and stop Palivizumab if less than 5 doses of Palivizumab given
III. Mechanism
- Nirsevimab is a Monoclonal Antibody that binds RSV fusion Protein, inhibiting fusion with host cell
- Prevents RSV viral entry into cells and subsequent replication
IV. Dosing
- Background
- Nirsevimab is given as a single IM Injection per season ($500/dose in 2023)
- Contrast with Palivizumab which is dosed monthly ($1800/dose in 2023)
- Give dose shortly before RSV season (or in the first week of life if born during RSV season)
- May be coadministered with other Vaccinations
- Nirsevimab is given as a single IM Injection per season ($500/dose in 2023)
- Season 1
- Weight <5 kg: 50 mg IM once per season (syringe with purple plunger rod)
- Weight >5 kg: 100 mg IM once per season (syringe with light-blue plunger rod)
- Season 2
- Give 200 mg IM (split into two 100 mg doses at different injection sites) once per season
V. Efficacy
- Prevents RSV hospitalization in normal risk infants for up to 5 months after injection (NNT 48)
- Similar efficacy in high risk infants as for Palivizumab (Synagis)
VI. Adverse Effects
- Rash (0.9%)
- Injection site inflammation such as pain, redness, swelling (0.03%)
- Hypersensitvity reaction (rare)
VII. Resources
VIII. References
- (2023) Presc Lett 30(10): 55-6
- LoVecchio (2024) Crit Dec Emerg Med 38(4); 34
- Simoes (2023) Lancet Child Adolesc Health 7(3): 180-9 [PubMed]