An antiviral drug active against influenza virus may reduce the effectiveness of FluMist. ACIP has recommended different intervals between the last dose of an antiviral medication and FluMist administration, based upon the half-life of the antiviral medication. The new recommendations are as follows:
- Oseltamivir or zanamivir: wait at least 48 hours after last dose before administering FluMist
- Peramivir: wait at least 5 days before administering FluMist
- Baloxavir: wait at least 17 days before administering FluMist
If any influenza antiviral medication must be given within 14 days after FluMist administration, the patient should be revaccinated without delay with any age-appropriate injectable influenza vaccine. All inactivated influenza vaccines and recombinant influenza vaccine (Flublok Quadrivalent) may be administered at any time relative to antiviral medication.