Vaccine Effectiveness & Efficacy

Offer fierce protection backed by years of vaccine effectiveness data1-4

Offer fierce protection backed by years of vaccine effectiveness data1-4

FLUMIST QUADRIVALENT (LAIV4) and IIV vaccine effectiveness (VE) data overlapped for all strains, demonstrating the general VE comparability during the seasons between 2016 and 20202-4*

Vaccine Effectiveness Chart Vaccine Effectiveness Chart

*There are no head-to-head clinical studies comparing LAIV4 and IIV. Results are descriptive only.

Unadjusted estimates.

IIV=inactivated influenza vaccine; LAIV4=quadrivalent live attenuated influenza vaccine; VE=vaccine effectiveness.


The effectiveness of FLUMIST QUADRIVALENT is based on data demonstrating1:

  • Clinical efficacy of trivalent FluMist® (Influenza Vaccine Live, Intranasal) in children and the efficacy of trivalent FluMist in adults
  • A comparison of postvaccination geometric mean titers (GMTs) of hemagglutination inhibition (HI) antibodies between individuals receiving trivalent FluMist and FLUMIST QUADRIVALENT
  • Clinical experience with trivalent FluMist is relevant to FLUMIST QUADRIVALENT because both vaccines are manufactured using the same process and have overlapping composition


  • FLUMIST QUADRIVALENT is contraindicated in persons who have had a severe allergic reaction (eg, anaphylaxis) to any vaccine component, including egg protein, or after a previous dose of any influenza vaccine, and in children and adolescents receiving concomitant aspirin or aspirin-containing therapy
  • In clinical trials, the risks of hospitalization and wheezing were increased in children <24 months of age who received trivalent FluMist
  • Children <5 years of age with recurrent wheezing and persons of any age with asthma may be at increased risk of wheezing following FLUMIST QUADRIVALENT administration. FLUMIST QUADRIVALENT has not been studied in persons with severe asthma or active wheezing
  • If Guillain-Barré syndrome has occurred within 6 weeks of any prior influenza vaccination, the decision to give FLUMIST QUADRIVALENT should be based on careful consideration of the potential benefits and risks
  • FLUMIST QUADRIVALENT has not been studied in immunocompromised persons
  • The safety of FLUMIST QUADRIVALENT in individuals with underlying medical conditions predisposing them to wild-type influenza infection complications has not been established
  • Appropriate medical treatment and supervision must be available to manage possible anaphylactic reactions following administration of the vaccine
  • FLUMIST QUADRIVALENT may not protect all individuals receiving the vaccine
  • The most common solicited adverse reactions (occurring ≥10% in vaccine recipients and at least 5% greater than in placebo) reported were runny nose or nasal congestion in persons 2-49 years, fever >100°F in children 2-6 years, and sore throat in adults 18-49 years. Among children 2-17 years who received FLUMIST QUADRIVALENT, 32% reported runny nose or nasal congestion and 7% reported fever >100°F. Among adults 18-49 years who received FLUMIST QUADRIVALENT, 44% reported runny nose or nasal congestion and 19% reported sore throat

FLUMIST QUADRIVALENT is a vaccine indicated for active immunization of persons 2-49 years of age for the prevention of influenza disease caused by influenza A subtype viruses and type B viruses contained in the vaccine. FLUMIST QUADRIVALENT is for intranasal administration only.

Please see full Prescribing Information for FLUMIST QUADRIVALENT, including Patient Information.

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