Candidates for Live‑Attenuated Intranasal Influenza Vaccine (LAIV, FluMist)
Use LAIV for non‑pregnant, otherwise healthy persons aged 2–49 years who lack high‑risk medical conditions and have no LAIV contraindications. 1, 2
Who IS a candidate (maximize morbidity/mortality/QoL benefit)
- Age 2–49 years, non‑pregnant, clinically healthy. 1, 2
- Prefers intranasal vaccine or would otherwise forgo vaccination if injection only is offered (improves coverage and outcomes). 3
- Not currently on, nor recently completed, influenza antivirals (avoid LAIV within 48 hours after antivirals; avoid starting antivirals for 14 days after LAIV). [Guideline text implies timing; follow ACIP principles] 4
- May be in close contact with individuals at increased risk (except those who are severely immunocompromised in protected environments), to reduce wild‑type transmission; use IIV instead if close contact is severely immunocompromised. 5
Who is NOT a candidate (contraindications/precautions)
Do NOT give LAIV in any of the following (choose IIV/RIV instead to optimize safety):
- Age <2 years or ≥50 years. 2
- Pregnancy. 2, 1
- Asthma or recurrent wheezing:
- Chronic conditions predisposing to complications (pulmonary, cardiovascular, renal, hepatic, neurologic/neuromuscular, hematologic, metabolic like diabetes). 2
- Immunocompromised state or close household contact with a severely immunocompromised person in a protected environment (use IIV). 5, 2
- Aspirin/salicylate therapy in ages 2–17 years (and avoid salicylates for 4 weeks after LAIV). 1, 2
- History of severe allergic reaction to any influenza vaccine, eggs, or LAIV components. 1, 2
- History of Guillain–Barré syndrome within 6 weeks of an influenza vaccine (precaution; prefer IIV or defer after risk–benefit). 2
- Moderate/severe acute illness; defer. Significant nasal congestion that may block delivery; defer or use IIV. 2
Practical selection algorithm
- Confirm age 2–49 years and non‑pregnant. If no → not LAIV. 1
- Screen exclusions: asthma/wheeze (esp. 2–4 y), chronic high‑risk conditions, immunocompromise, salicylates (2–17 y), severe allergy to vaccine/eggs, prior GBS (precaution), recent/ongoing antivirals, severe illness/nasal congestion, close contact with severely immunocompromised in protected setting. If any → use IIV/RIV instead. 2, 5, 2, 1
- If eligible and will accept intranasal vaccine, give LAIV:
- Dose: 0.2 mL intranasal (0.1 mL per nostril) once annually for ages ≥9 years. Children 2–8 years may need 2 doses ≥4 weeks apart depending on prior influenza vaccination history. No repeat if sneezes. 1, 2
- Counsel on mild URI‑type adverse effects; advise avoiding salicylates for 4 weeks (ages 2–17). 1
- Advise avoiding contact with severely immunocompromised patients (protected environment) for 7 days after LAIV. 5
Evidence notes and nuances
- Current US indications: LAIV is licensed for ages 2–49 years, non‑pregnant, healthy; no preference over IIV is made by ACIP within indications. 2, 1
- AAP has permitted LAIV as an option to improve uptake when IIV would be refused, but emphasizes IIV as primary choice due to variable effectiveness in some seasons; this supports offering LAIV to eligible healthy children to improve vaccination rates and outcomes. 3
- Past reduced effectiveness against A(H1N1)pdm09 led to temporary non‑use; ACIP reinstated LAIV as an option in 2018–19 with updated strain, reflecting evolving performance; no current preferential recommendation. This underscores selecting LAIV only in appropriate candidates. 6
Common pitfalls to avoid
- Giving LAIV to children 2–4 years with recent wheezing or any patient with asthma/chronic diseases—use IIV/RIV. 2, 1
- Administering to pregnant persons or to those on salicylates (ages 2–17). 2, 1
- Using LAIV in egg‑anaphylactic patients—prefer egg‑free RIV (ages 18–49) or appropriate IIV protocols. 2
- Administering soon after influenza antivirals or with significant nasal congestion—delay or use IIV. 4, 2