Groups 1 and 2: Geometric Mean Concentrations (GMCs) of Antibodies Measured by Spiked-Enzyme-linked Immunosorbent Assay (S-ELISA) 28 Days After Administration of Ad26.COV2.S Vaccine;Groups 1 and 2: Geometric Mean Titers (GMTs) of Hemagglutination Inhibition (HI) Antibodies Against Each of the Four Influenza Vaccine Strains 28 Days After the Administration of a Seasonal Quadrivalent Standard-dose Influenza Vaccine

Groups 1 and 2: Geometric Mean Concentrations (GMCs) of Antibodies Measured by Spiked-Enzyme-linked Immunosorbent Assay (S-ELISA) 28 Days After Administration of Ad26.COV2.S Vaccine;Groups 1 and 2: Geometric Mean Titers (GMTs) of Hemagglutination Inhibition (HI) Antibodies Against Each of the Four Influenza Vaccine Strains 28 Days After the Administration of a Seasonal Quadrivalent Standard-dose Influenza Vaccine

Groups 1 and 2: HAI Titers (Geometric Mean Titers [GMTs]) of Hemagglutination Inhibition (HI) Antibody Against each of the 4 Influenza Vaccine Strains 28 Days after the Administration of a Seasonal Quadrivalent Standard-dose Influenza Vaccine;Groups 1 and 2: Spiked-Enzyme-linked Immunosorbent Assay (S-ELISA) Titers Geometric Mean Concentrations (GMCs) Titers 28 Days After the Administration of Ad26.COV2.S Vaccine

Groups 1 and 2: HAI Titers (Geometric Mean Titers [GMTs]) of Hemagglutination Inhibition (HI) Antibody Against each of the 4 Influenza Vaccine Strains 28 Days after the Administration of a Seasonal Quadrivalent Standard-dose Influenza Vaccine;Groups 1 and 2: Spiked-Enzyme-linked Immunosorbent Assay (S-ELISA) Titers Geometric Mean Concentrations (GMCs) Titers 28 Days After the Administration of Ad26.COV2.S Vaccine

None

Groups 1 and 2: HAI Titers (Geometric Mean Titers [GMTs]) of Hemagglutination Inhibition (HI) Antibody Against each of the 4 Influenza Vaccine Strains 28 Days after the Administration of a Seasonal Quadrivalent Standard-dose Influenza Vaccine [ Time Frame: 28 days after the administration of a seasonal quadrivalent standard-dose influenza vaccine (Day 29) ] Hemagglutinin Inhibition Assay (HAI) titers GMT of HI antibody against each of the 4 influenza vaccine strains 28 days after the administration of a seasonal quadrivalent standard-dose influenza vaccine will be reported. Groups 1 and 2: Spiked-Enzyme-linked Immunosorbent Assay (S-ELISA) Titers Geometric Mean Concentrations (GMCs) Titers 28 Days After the Administration of Ad26.COV2.S Vaccine [ Time Frame: 28 days after the administration of Ad26.COV2.S vaccine (Day 29) ] Non-inferiority (NI) will be assessed in terms of humoral immune response expressed by the GMCs titers of S-ELISA titers, 28 days after the administration of Ad26.COV2.S vaccine.

Groups 1 and 2: HAI Titers (Geometric Mean Titers [GMTs]) of Hemagglutination Inhibition (HI) Antibody Against each of the 4 Influenza Vaccine Strains 28 Days after the Administration of a Seasonal Quadrivalent Standard-dose Influenza Vaccine;Groups 1 and 2: Spiked-Enzyme-linked Immunosorbent Assay (S-ELISA) Titers Geometric Mean Concentrations (GMCs) Titers 28 Days After the Administration of Ad26.COV2.S Vaccine

Groups 1 and 2: HAI Titers (Geometric Mean Titers [GMTs]) of Hemagglutination Inhibition (HI) Antibody Against each of the 4 Influenza Vaccine Strains 28 Days after the Administration of a Seasonal Quadrivalent Standard-dose Influenza Vaccine;Groups 1 and 2: Spiked-Enzyme-linked Immunosorbent Assay (S-ELISA) Titers Geometric Mean Concentrations (GMCs) Titers 28 Days After the Administration of Ad26.COV2.S Vaccine

Groups 1 and 2: Geometric Mean Titers (GMTs) of Hemagglutination Inhibition (HI) Antibody Against each of the 4 Influenza Vaccine Strains at 28 Days After the Administration of a Seasonal Quadrivalent Standard-dose Influenza Vaccine;Groups 1 and 2: Spiked-Enzyme-linked Immunosorbent Assay (S-ELISA) Geometric Mean Concentrations (GMCs) 28 Days After the Administration of Ad26.COV2.S Vaccine;Groups 3 and 4: GMT of HI Antibody Against each of the 4 Influenza Vaccine Strains at 28 Days After the Administration of a Seasonal Quadrivalent High-dose Influenza Vaccine;Groups 3 and 4: S-ELISA GMCs 28 Days After the Administration of Ad26.COV2.S Vaccine

Groups 1 and 2: Geometric Mean Titers (GMTs) of Hemagglutination Inhibition (HI) Antibody Against each of the 4 Influenza Vaccine Strains at 28 Days After the Administration of a Seasonal Quadrivalent Standard-dose Influenza Vaccine;Groups 1 and 2: Spiked-Enzyme-linked Immunosorbent Assay (S-ELISA) Geometric Mean Concentrations (GMCs) 28 Days After the Administration of Ad26.COV2.S Vaccine;Groups 3 and 4: GMT of HI Antibody Against each of the 4 Influenza Vaccine Strains at 28 Days After the Administration of a Seasonal Quadrivalent High-dose Influenza Vaccine;Groups 3 and 4: S-ELISA GMCs 28 Days After the Administration of Ad26.COV2.S Vaccine