Immunogenicity and safety of a cell culture-derived inactivated quadrivalent influenza vaccine (NBP607-QIV) in South Korean children and adolescents: A randomized, double-blind, multi-center, phase 3 clinical trial

Background: Cell culture-derived influenza vaccines have several important advantages over egg-based influenza vaccines and inactivated quadrivalent influenza vaccine (IIV4) may offer broader protection against seasonal influenza than inactivated trivalent influenza vaccine (IIV3) by containing one more B strain. This study examined the immunogenicity and safety of a cell culture-derived IIV4 candidate vaccine in children and adolescents.

Methods: This phase III, randomized, double-blind, multicenter trial in children/adolescents (6 month through 18 years) was conducted in South Korea. Children/adolescents were randomized 4:1 to receive one of novel cell culture-derived, subunit, IIV4 (NBP607-QIV, SK Chemicals, Seongnam, Korea) or licensed IIV3 (Agrippal^®S1, Novartis Vaccines and Diagnostics Srl, Siena, Italy). Hemagglutination inhibition antibody titers were assessed pre-vaccination and 28 days post-vaccination. Safety data were collected for up to 6 months post-vaccination.

Results: 366 children/adolescents received IIV4, and 88 children/adolescents received IIV3. Overall, NBP607-QIV met the immunogenicity criteria of Committee for Medicinal Products for Human Use for each of the 4 strains. Between the NBP607-QIV and control groups, mmunogenicity endpoints were comparable. Participants younger than 3 years of age had lower immunologic responses against 2 influenza B strains in both NBP607-QIV and control group. No deaths, vaccine-related SAEs, or withdrawals because of adverse events were reported. The solicited adverse events reported were generally of mild intensity.

Conclusion: NBP607-QIV, a novel cell culture-derived IIV4, showed good immunogenicity to all 4 influenza strains and had tolerable safety profiles in children and adolescents. Moreover, NBP607-QIV was more immunogenic against influenza B compared to the control, an egg-based subunit vaccine.