Study to Evaluate the Immunogenicity and Safety of 2 Formulations of GlaxoSmithKline (GSK) Biologicals' GSK1247446A Low Dose Influenza Vaccine Candidate

Influenza strains assessed were the A/New Caledonia (A/CAL), A/Wisconsin (A/WIS), B/Malaysia (B/MAL) strains. Titers were presented as geometric mean titers (GMTs) calculated on subjects with available results, and expressed in haemagglutination-inhibition unit (HIU), e. g. the dilution of a serum haemagglutination-inhibition containing the specific antibody each of the assessed influenza strains at which the solution retained the minimum level of activity needed to neutralize or precipitate the corresponding influenzae antigen. The seropositivity cut-off value of the assay was 10 HIU.

A seroprotected subject was a subject whose antibody titer against each of the influenza strains assessed (A/New Caledonia (A/CAL), A/Wisconsin (A/WIS) and B/Malaysia (B/MAL) strains) was equal to or higher than (>=) the assay seroprotection cut-off value of 40 haemagglutination-inhibition units (HIU) (e. g. the dilution of a serum haemagglutination-inhibition containing the specific antibody each of the assessed influenza strains at which the solution retained the minimum level of activity needed to neutralize or precipitate the corresponding influenzae antigen).

Influenza strains assessed were the A/New Caledonia (A/CAL), A/Wisconsin (A/WIS), and B/Malaysia (B/MAL) strains. A seroconverted subject was a subject who had either a pre-vaccination serum HI antibody titer lower than 10 haemagglutination-inhibition units (HIU) (e. g. the dilution of a serum haemagglutination-inhibition containing the specific antibody each of the assessed influenza strains at which the solution retained the minimum level of activity needed to neutralize or precipitate the corresponding influenzae antigen) and a post-vaccination titer higher than or equal to 40 HIU, or a pre-vaccination titer >= 10 and at least a four-fold increase in post- vaccination titer.

Influenza strains assessed were the A/New Caledonia (A/CAL), A/Wisconsin (A/WIS), and B/Malaysia (B/MAL) strains. The seroconversion factor (SCF) was defined as a ratio, as the fold increase in serum haemagglutination-inhibition geometric mean titers (GMTs) post-vaccination compared to Day 0 (with GMTs in the above calculation expressed in haemagglutination-inhibition units (HIU) [e. g. the dilution of a serum haemagglutination-inhibition containing the specific antibody each of the assessed influenza strains at which the solution retained the minimum level of activity needed to neutralize or precipitate the corresponding influenza antigen]).

Assessed solicited local symptoms were ecchymosis, pain, redness and swelling the site of injection. Any = occurrence of a solicited local symptom regardless of intensity grade. Grade 3 pain = Pain which prevented normal activity. Grade 3 ecchymosis/redness/swelling = ecchymosis/redness/swelling at injection site with a diameter larger than (>) 50 millimeters (mm). All solicited local symptoms assessed were considered by the investigator as causally related to the study vaccination.

Assessed solicited general symptoms were arthralgia, fatigue, fever (axillary temperature higher than or equal to (>=) 37.5 degrees Celsius (°C)), headache, muscle aches, and shivering. Any = Occurrence of a particular symptom regardless of intensity or relationship to vaccination. Grade 3 symptom = Symptom which prevented normal activity. Related = Symptom assessed by the investigator as causally related to the study vaccination. Grade 3 fever = axillary temperature higher than 39.0°C.

An unsolicited AE is any untoward medical occurrence in a patient or clinical investigation subject, temporally associated with use of a medicinal product, whether or not considered related to the medicinal product. Any AE = any occurrence of an AE, regardless of intensity or relationship to study vaccination. Grade 3 = an event that prevented normal activity. Related = event assessed by the investigator as causally related to the study vaccination.

SAEs assessed include medical occurrences that result in death, are life threatening, require hospitalization or prolongation of hospitalization, result in disability/incapacity or are a congenital anomaly/birth defect in the offspring of a study subject. Any SAE = any occurrence of an SAE, regardless of relationship to study vaccination. A related SAE = an SAE assessed by the investigator as causally related to the study vaccination.