A Study to Evaluate the Reactogenicity, Safety and Immunogenicity of GlaxoSmithKline (GSK) Biologicals' Investigational Supra-seasonal Universal Influenza Vaccines - Inactivated (SUIVs) (GSK3816302A) in Healthy Adults Aged 18 to 39 Years

1 Primary dose or 1 Booster dose of Supraseasonal Universal Influenza Vaccine (Flu D-SUIV), chimeric strain cH8/1N1 with Adjuvant System 03 (AS03) was administered intramuscularly (IM) in the deltoid region of non-dominant arm.

1 Primary dose or 1 Booster dose of Supraseasonal Universal Influenza Vaccine (Flu D-SUIV), chimeric strain cH5/1N1 with Adjuvant System 03 (AS03) was administered IM in the deltoid region of non-dominant arm.

1 Booster dose of Supraseasonal Universal Influenza Vaccine (Flu D-SUIV), chimeric strain cH11/1N1 with Adjuvant System 03 (AS03) was administered IM in the deltoid region of non-dominant arm.

1 Primary dose or 1 Booster dose of Supraseasonal Universal Influenza Vaccine (Flu D-SUIV), chimeric strain cH8/1N1 with Adjuvant System 01 (AS01) was administered IM in the deltoid region of non-dominant arm.

1 Primary dose or 1 Booster dose of Supraseasonal Universal Influenza Vaccine (Flu D-SUIV), chimeric strain cH5/1N1 with Adjuvant System 01 (AS01) was administered IM in the deltoid region of non-dominant arm.

1 Booster dose of Supraseasonal Universal Influenza Vaccine (Flu D-SUIV), chimeric strain cH11/1N1 with Adjuvant System 01 (AS01) was administered IM in the deltoid region of non-dominant arm.

1 Primary dose or 1 Booster dose of Supraseasonal Universal Influenza Vaccine (Flu D-SUIV), chimeric strain cH8/1N1 without adjuvant was administered IM in the deltoid region of non-dominant arm.

1 Primary dose or 1 Booster dose of Supraseasonal Universal Influenza Vaccine (Flu D-SUIV), chimeric strain cH5/1N1 without adjuvant was administered IM in the deltoid region of non-dominant arm.

1 Booster dose of Supraseasonal Universal Influenza Vaccine (Flu D-SUIV), chimeric strain cH11/1N1 without adjuvant was administered IM in the deltoid region of non-dominant arm.

1 dose of Phosphate Buffered Saline (PBS) was administered IM in the deltoid region of non-dominant arm.

1 Primary dose and 1 Booster dose was administered IM in the deltoid region of non-dominant arm.