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– A phase 3, non‑randomised immunobridging study (NCT05513053) compared immune responses to a single dose of recombinant quadrivalent influenza vaccine (RIV4) in 9–17‑year‑olds versus 18–49‑year‑olds during the 2022–23 northern hemisphere season.
– Haemagglutination inhibition (HAI) geometric mean titre (GMT) ratios for all four strains met the pre‑specified non‑inferiority criteria; seroconversion differences were also consistent with non‑inferiority for each strain.
