biostudies-literatureRodriguez-Guilarte LNCIPC CDC HHS407https://www.ebi.ac.uk/biostudies/studies/S-EPMC12796199biostudies-literatureUnknown17(1)Annual vaccination is an effective strategy for preventing severe disease caused by seasonal influenza. Quadrivalent influenza vaccines (QIVs) protect against two strains of influenza A and two strains of influenza B, thereby enhancing the host antiviral neutralizing antibody response and inducing CD4⁺ and CD8⁺ T cell responses. Here, we report findings from a randomized, double-blind, active-controlled phase 3 clinical trial (NCT05431725) that includes 334 healthy adults aged 18-64 years and evaluates the humoral and cellular antiviral immune responses induced by two inactivated QIVs, Sinovac-QIV and Vaxigrip-Tetra™. The primary endpoint of the study is the specific antibody responses measured by hemagglutination inhibition (HAI) assays 28 days post-vaccination, whilNature communicationsInfluenza vaccines promote humoral and cellular immune responses: a randomized, double-blind, phase 3 trial.PMC12796199U17 CE002021Rios MPalacios PABascur FCastejon ARodriguez-Guilarte LAljaro SCabrera AAlvarez-Figueroa MJDel Rio CVillarroel MRoman FGonzalez PAFeijoo RMGrandon STwele LPerez CMPerez LFernandez Vasquez PEGutierrez-Vera CReyes AJara PCalvo MBueno SMXin QRojas AGonzalez-Aramundiz JVOyonarte MSchilling AAngelica Dominguez MMoreno-Tapia DBeltran Campos DTovar De Sousa CYang WKalergis AMMendez CPenaloza HFRivera DBCarreno LJAstudillo PfalseInfluenza vaccines promote humoral and cellular immune responses: a randomized, double-blind, phase 3 trial.Annual vaccination is an effective strategy for preventing severe disease caused by seasonal influenza. Quadrivalent influenza vaccines (QIVs) protect against two strains of influenza A and two strains of influenza B, thereby enhancing the host antiviral neutralizing antibody response and inducing CD4⁺ and CD8⁺ T cell responses. Here, we report findings from a randomized, double-blind, active-controlled phase 3 clinical trial (NCT05431725) that includes 334 healthy adults aged 18-64 years and evaluates the humoral and cellular antiviral immune responses induced by two inactivated QIVs, Sinovac-QIV and Vaxigrip-Tetra™. The primary endpoint of the study is the specific antibody responses measured by hemagglutination inhibition (HAI) assays 28 days post-vaccination, whil2025-01-01T00:00:00Z2025 Dec2026-07-15T12:24:35.297Z2026-07-04T03:13:27.474ZS-EPMC127961994135473810.1038/s41467-025-67102-y