Immunogenicity and safety of recombinant influenza vaccine versus standard inactivated influenza vaccine in children aged 3 to 8 years: results from a phase III randomised study

Abstract: 

"Influenza vaccines for those aged <9 years old are limited to the standard-dose inactivated influenza vaccine (IIV) and live-attenuated intranasal influenza vaccine. In this Phase III, modified double-blind, active-controlled trial, participants aged 3–8 years were randomised in a 1:1 ratio to receive the quadrivalent recombinant influenza vaccine (RIV4) or quadrivalent inactivated influenza vaccine (IIV4). The non-inferiority of immune responses was assessed using geometric mean titre ratios (GMTRs) 28 days after the last vaccine administration and seroconversion rates (NCT05513391). A futility analysis was conducted after approximately 25% of the overall sample size was enrolled. Of the 1412 participants planned, 366 participants were enrolled in the United States, Poland, and Spain, resulting in a lower overall study power. The RIV4 induced non-inferior immune responses to those for IIV4 for the A/H1N1, A/H3N2, and B/Yamagata strains but not for the B/Victoria strain. Both vaccines were well tolerated with no safety concerns."

Folegatti, P.M., Pepin, S., Tabar, C., Fries, K., Talanova, O., See, S., Kaas-Leach, K. and De Bruijn, I. (2026). Immunogenicity and safety of recombinant influenza vaccine versus standard inactivated influenza vaccine in children aged 3 to 8 years: results from a phase III randomised study. Vaccine, 82, p.128582.