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General Information
FluMist Quadrivalent is a vaccine indicated for active immunization for the prevention of influenza disease caused by influenza A subtype viruses and type B viruses contained in the vaccine.
FluMist Quadrivalent is approved for use in persons 2 through 49 years of age.
Flumist Quadrivalent is supplied as an intranasal mist. Administer FluMist Quadrivalent according to the following schedule:
- 2 years through 8 years: 1 or 2 doses 0.2 mL each. If 2 doses, administer at least 1 month apart.
- 1 or 2 doses depends on history as per Advisory Committee on Immunization Practices annual recommendations on prevention and control of influenza with vaccines.
- 9 years through 49 years: 1 dose, 0.2 mL
Each sprayer contains a single dose (0.2 mL) of FluMist Quadrivalent. Administer approximately one half of the contents of the single-dose intranasal sprayer into each nostril.
Mechanism of Action
Immune mechanisms conferring protection against influenza following receipt of FluMist Quadrivalent vaccine are not fully understood; serum antibodies, mucosal antibodies, and influenza-specific T cells may play a role. FluMist and FluMist Quadrivalent contain live attenuated influenza viruses that must infect and replicate in cells lining the nasopharynx of the recipient to induce immunity. Vaccine viruses capable of infection and replication can be cultured from nasal secretions obtained from vaccine recipients (shedding).
Side Effects
Adverse effects associated with the use of FluMist Quadrivalent may include, but are not limited to, the following:
- runny nose or nasal congestion (ages 2 years through 49 years)
- fever over 100°F (children ages 2 years through 6 years)
- sore throat (adults ages 18 years through 49 years)
Clinical Trial Results
Pediatric Study
FDA pediatric approval was based on a multi-center, randomized,
double-blind, placebo-controlled trial enrolling over 4719 healthy
children and was designed to evaluate the efficacy of FluMist
against culture confirmed influenza over two successive seasons.
The primary endpoint for the first year of the trial was the
prevention of culture-confirmed influenza illness due to
antigenically matched wild-type influenza in healthy children who
received two doses of vaccine.
Results showed that subject’s 60-71 months of age who received two doses of vaccine compared with placebo experienced a significant reduction in the incidence of culture-confirmed influenza. Additionally, children who received one doses of vaccine compared to one dose of placebo experienced a significant reduction in the incidence of culture-confirmed influenza. Roughly, 85% of subject in the first year returned for the second year of the Pediatric Efficacy Study, including a subset of 544 children 60-84 months of age.
During the second year of the trial, children remained in the same treatment group as in year one and received a single dose of FluMist or placebo. The primary endpoint of the trial was the prevention of culture-confirmed influenza illness due to antigenically matched wild-type influenza after a single annual revaccination dose of FluMist. In the subset of 544 children 60-84 months of age, illness associated with culture-confirmed illness in the second year was similar in scope and severity to that in the first year. The overall efficacy of FluMist against culture-confirmed wild-type influenza, regardless of antigenic match, was 86.9%.
Adult Study
FDA adult approval was based on a multi-center, randomized, double
blind, placebo-controlled trial enrolling 3920 healthy adults 18-49
years of age. The trial was designed to evaluate the effectiveness
of FluMist in the reduction of influenza-like illness during the
peak influenza outbreak period at each site, based on community
surveillance. The efficacy against culture confirmed influenza was
not assessed. The primary endpoint of the trial was the reduction
in the proportion of participants with one or more episodes of any
febrile illness (AFI). Adults had AFI if they had symptoms for at
least two days with fever on at least one day and if they had two
or more symptoms (fever, chills, headache, runny nose, sore throat,
cough, muscle aches, tiredness/weakness) on at least one day. Two
other influenza-like illness definitions were also assessed: severe
febrile illness (SFI), and febrile upper respiratory illness
(FURI). SFI was defined as having at least three consecutive days
of symptoms, at least one day of fever, and two or more symptoms on
at least three days. FURI was defined as at least two consecutive
days of upper respiratory infection (URI) symptoms (runny nose,
sore throat, or cough), fever on at least one day, and at least two
URI symptoms on at least one day. Results showed that during the
outbreak period, FluMist subject did not experience a significant
reduction in AFI; however, significant reductions were observed for
SFI and FURI.
The efficacy in adults was also demonstrated in a vaccine challenge study. The multi-center, randomized, double-blind, placebo-controlled study enrolled healthy adults 18-41 years of age who were serosusceptible to at least one strain included in the vaccine. Adults were randomized to receive FluMist or placebo. Laboratory-documented influenza illness due to all three strains combined was reduced compared to placebo by 85% in FluMist recipients.