A Randomized, Double-blind, Active-controlled Clinical Trial of a Cell Culture-derived Inactivated Trivalent Influenza Vaccine (NBP607) in Healthy Children 6 Months Through 18 Years of Age

Background: Although a number of cell culture–derived influenza vaccines have been approved for use in adults, there have been few clinical trials of cell culture–derived seasonal influenza vaccines for young children. Methods: We conducted a randomized, double-blind phase III clinical trial to evaluate the safety and immunogenicity of a cell culture–derived subunit trivalent inactivated influenza vaccine (NBP607, SK Chemicals Co., Ltd., Seongnam, Korea) in healthy children 6 months of age through 18 years. Subjects were randomized to receive either a study vaccine or an egg-based control vaccine. Antibody levels were measured by the hemagglutination inhibition assay, using cell-derived antigens. Solicited adverse events were assessed for 7 days after each injection. Serious adverse events were collected for 6 months after vaccination. Results: A total of 374 participants completed the study. No deaths, vaccine-related serious adverse events or withdrawals resulting from adverse events were reported. Rates of solicited and unsolicited adverse events were similar in 2 groups. Overall, NBP607 met the immunogenicity criteria of the Committee for Proprietary Medicinal Products for the 3 influenza strains. Between the NBP607 group and the control group, immunogenicity endpoints were comparable. Participants younger than 3 years of age had lower immunologic responses against the influenza B virus in both the NBP607 group and the control group. Conclusions: The immunogenicity and safety were comparable between the NBP607 group and the control group. NBP607 is well tolerated and immunogenic in children 6 months of age through 18 years.