Clinical Trial Info

Safety, Reactogenicity and Immunogenicity of Flublok Quadrivalent (Recombinant Influenza Vaccine,Seasonal Formulation)

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Flublok was studied previously in children 6 -59 months of age and demonstrated less than satisfactory immunogenicity results, especially in the 6-36 month age group. Thus, the initial introduction of Flublok Quadrivalent Formulation (RIV4) into the pediatric population will evaluate immunogenicity and safety in older children and adolescents, aged 6-17. This clinical trial is designed to demonstrate the safety and non-inferior immunogenicity of Flublok-Q in pediatric subjects 6-17 years of age as compared to IIV4. Positive results in this study may support further studies in younger children.


Pediatrics published the results of this study in May 2018.

Results: Both vaccines were well tolerated in both age groups, and long-term follow-up revealed no vaccine-related adverse events. Overall, immunogenicity (geometric mean titers and seroconversion rate differences) provided comparable antibody responses to most antigens in both vaccines in the older subjects. Low responses to the influenza B Victoria lineage in both vaccines made interpretation difficult. Immunogenicity in younger children was similar, but the truncated sample size was insufficient to support noninferiority comparisons.

Conclusions: Despite low responses to influenza B lineages in both vaccines, the RIV4 provided safety and immunogenicity that were comparable to those of the licensed inactivated vaccine in pediatric subjects, which was most convincing in those aged 9 to 17 years. Future confirmatory clinical efficacy trials may be used to support the recombinant influenza vaccine as an alternative for the pediatric age group of ≥6 years.