Immunogenicity and safety of a quadrivalent recombinant influenza vaccine manufactured in Iran (FluGuard) in volunteers aged 18-60 years: A double-blind, non-inferiority, randomized controlled trial.

BACKGROUND:This study aimed to evaluate the non-inferiority of the FluGuard (a quadrivalent recombinant vaccine manufactured by Nivad Pharmed Salamat Company in Iran) by comparing its immunogenicity and safety with Vaxigrip Tetra (a quadrivalent inactivated vaccine manufactured by Sanofi Pasteur in France). MATERIALS AND METHODS:In this double-blind, randomized controlled trial, eligible volunteers aged 18-60 were randomized to receive either FluGuard or Vaxigrip Tetra vaccines. Immunogenicity was evaluated using the Hemagglutination Inhibition (HAI) assay and reported with the geometric mean titer (GMT), seroprotection, and seroconversion. In addition, vaccine safety was assessed by interviewing participants through phone calls. RESULTS:Out of 110 randomized volunteers, 51 and 53 were entered into the final analysis in the Vaxigrip and FluGuard groups, respectively. Vaxigrip had a higher seroprotection rate for the H1N1 strain compared with FluGuard (98 % vs. 91 %). Besides, FluGuard had higher seroprotection rates for H3N2 (74 % vs. 69 %), B-Yamagata (87 % vs. 84 %), and B-Victoria (66 % vs. 41 %) strains compared with Vaxigrip. In all four strains, FluGuard was non-inferior to Vaxigrip with the upper bounds of the 95 % CI on the ratio of the GMTs < 1.5: H1N1 (1.25), H3N2 (0.94), B-Yamagata (0.62), and B-Victoria (0.59). Furthermore, FluGuard was non-inferior to Vaxigrip with the upper bounds of the 95 % CI on the difference between the seroconversion rates < 10 %: H1N1 (2 %), H3N2 (10 %), B-Yamagata (-10 %), and B-Victoria (-29 %). The prevalence of solicited adverse drug reactions did not differ between groups. Furthermore, participants did not experience serious adverse events. CONCLUSION:Our findings support the non-inferiority of the FluGuard vaccine to the Vaxigrip vaccine regarding immunogenicity and safety. CLINICAL TRIAL REGISTRY:The study protocol was approved by the Iranian Registry of Clinical Trials (IRCT20210901052358N5).