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Clinical Trial
. 2015 Mar 1;211(5):801-10.
doi: 10.1093/infdis/jiu548. Epub 2014 Oct 6.

AS03B-adjuvanted H5N1 influenza vaccine in children 6 months through 17 years of age: a phase 2/3 randomized, placebo-controlled, observer-blinded trial

Affiliations
Clinical Trial

AS03B-adjuvanted H5N1 influenza vaccine in children 6 months through 17 years of age: a phase 2/3 randomized, placebo-controlled, observer-blinded trial

Pope Kosalaraksa et al. J Infect Dis. .

Abstract

Background: This phase 2/3, randomized, placebo-controlled, observer-blinded study assessed the immunogenicity, reactogenicity, and safety of an inactivated, split-virion H5N1 influenza vaccine (A/Indonesia/5/2005) in children aged 6 months through 17 years.

Methods: Children received 2 influenza vaccine doses 21 days apart, each containing 1.9 µg of hemagglutinin and AS03B adjuvant (5.93 mg of α-tocopherol). The randomization ratio was 8:3 for vaccine to placebo, with equal allocation between 3 age strata (6-35 months, 3-8 years, and 9-17 years). Immunogenicity against the vaccine strain was assessed 21 days after the first and second vaccine doses for all vaccinees, at day 182 for half, and at day 385 for the remaining half. Reactogenicity after each dose and safety up to 1 year after vaccination were evaluated.

Results: Within each age stratum, the lower limit of the 98.3% confidence interval for the day 42 seroprotection rate was ≥70%, thus fulfilling the US and European licensure criteria. The immune responses elicited by vaccine persisted well above baseline levels for 1 year. The vaccine was more reactogenic than placebo, but no major safety concerns were identified.

Conclusions: AS03B-adjuvanted H5N1 influenza vaccine was immunogenic and showed an acceptable safety profile in all age groups studied. Clinical Trials Registration: NCT01310413.

Keywords: AS03B; H5N1; Prepandrix™; adjuvant; influenza vaccine; pandemic.

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Figures

Figure 1.
Figure 1.
Selection and flow of subjects through the study. Abbreviations: AE, adverse event; TVC, total vaccinated cohort.
Figure 2.
Figure 2.
Hemagglutination inhibition (HI) seroprotection rates (A), seroconversion rates (B), and mean geometric increase (C) in the per-protocol immunogenicity cohort, by age stratum. Seroprotection rate was defined as the percentage of children with HI titers of ≥1:40 following vaccination; seroconversion rate was defined as the percentage of children achieving an increase in HI titer from <1:10 to ≥1:40 or at least a 4-fold postvaccination increase in HI titer from a prevaccination titer of ≥1:10. Abbreviation: CI, confidence interval.
Figure 3.
Figure 3.
Solicited injection site events (A) and general solicited adverse events (B and C) in the total vaccinated cohort, by age stratum. Grade 3 fever was defined as a temperature of ≥39°C (≥102.2°F). Data are shown as events/child. Abbreviations: CI, confidence interval; GI, gastrointestinal.

References

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