Seroconversion rate (SCR) was defined as the number of subjects who have either a pre-vaccination reciprocal HI titer < 10 and a post-vaccination reciprocal titer ≥ 40, or a pre-vaccination reciprocal HI titer ≥ 10 and at least a 4-fold increase in post vaccination reciprocal titer against the vaccine virus.

The According-To-Protocol cohort for immunogenicity at Day 164 included subjects who had not received a vaccine not specified in the protocol during the primary vaccination course, for whom 3 doses were administered and assay results were available for antibodies against H1N1 antigen at day 21 after the second H1N1 vaccine dose (Day 164).

Seroprotection rate (SPR) was defined as the number of subjects with H1N1 reciprocal HI titers ≥ 40 against the tested vaccine virus.

The According-To-Protocol cohort for immunogenicity at Day 164 included subjects who had not received a vaccine not specified in the protocol during the primary vaccination course, for whom 3 doses were administered and assay results were available for antibodies against H1N1 antigen at day 21 after the second H1N1 vaccine dose (Day 164).

Geometric mean fold-rise (GMFR), or seronversion factor (SCF), was defined as the geometric mean of the within-subject ratios of the post-vaccination reciprocal HI titer to the pre-vaccination reciprocal HI titer for the vaccine virus.

The According-To-Protocol cohort for immunogenicity at Day 164 included subjects who had not received a vaccine not specified in the protocol during the primary vaccination course, for whom 3 doses were administered and assay results were available for antibodies against H1N1 antigen at day 21 after the second H1N1 vaccine dose (Day 164).

A seropositive subject was a subject whose HI antibody titer was greater than or equal to the assay cut-off value of 1:10.

The According-To-Protocol cohort for immunogenicity at Day 164 included subjects who had not received a vaccine not specified in the protocol during the primary vaccination course, for whom 3 doses were administered and assay results were available for antibodies against H1N1 antigen at day 21 after the second H1N1 vaccine dose (Day 164).

Titers were expressed as geometric mean antibody titers (GMTs).

The According-To-Protocol cohort for immunogenicity at Day 164 included subjects who had not received a vaccine not specified in the protocol during the primary vaccination course, for whom 3 doses were administered and assay results were available for antibodies against H1N1 antigen at day 21 after the second H1N1 vaccine dose (Day 164).

VRR for microneutralization titers was defined as the incidence rate of vaccinees with at least a 4-fold increase in post vaccination reciprocal titer relative to Day 0. The cut-off value for microneutralization titers is 1:28.

The According-To-Protocol cohort for immunogenicity at Day 164 included subjects who had not received a vaccine not specified in the protocol during the primary vaccination course, for whom 3 doses were administered and assay results were available for antibodies against H1N1 antigen at day 21 after the second H1N1 vaccine dose (Day 164).

Seroconversion rate (SCR) was defined as the number of subjects who have either a pre-vaccination reciprocal HI titer < 1:10 and a post-vaccination reciprocal titer ≥ 1:40, or a pre-vaccination reciprocal HI titer ≥ 10 and at least a 4-fold increase in post vaccination reciprocal titer against the vaccine virus.

The According-To-Protocol cohort for immunogenicity at Day 164 included subjects who had not received a vaccine not specified in the protocol during the primary vaccination course, for whom 3 doses were administered and assay results were available for antibodies against H1N1 antigen at day 21 after the second H1N1 vaccine dose (Day 164).

Seroprotection rate (SPR) was defined as the number of subjects with H1N1 reciprocal HI titers ≥ 1:40 against the tested vaccine virus.

The According-To-Protocol cohort for immunogenicity at Day 164 included subjects who had not received a vaccine not specified in the protocol during the primary vaccination course, for whom 3 doses were administered and assay results were available for antibodies against H1N1 antigen at day 21 after the second H1N1 vaccine dose (Day 164).

Geometric mean fold-rise (GMFR), or seronversion factor (SCF), was defined as the geometric mean of the within-subject ratios of the post-vaccination reciprocal HI titer to the pre-vaccination reciprocal HI titer for the vaccine virus.

The According-To-Protocol cohort for immunogenicity at Day 164 included subjects who had not received a vaccine not specified in the protocol during the primary vaccination course, for whom 3 doses were administered and assay results were available for antibodies against H1N1 antigen at day 21 after the second H1N1 vaccine dose (Day 164).

A seropositive subject was a subject whose HI antibody titer was greater than or equal to the assay cut-off value of 1:10.

The According-To-Protocol cohort for immunogenicity at Day 164 included subjects who had not received a vaccine not specified in the protocol during the primary vaccination course, for whom 3 doses were administered and assay results were available for antibodies against H1N1 antigen at day 21 after the second H1N1 vaccine dose (Day 164).

Titers were expressed as geometric mean antibody titers (GMTs).

The According-To-Protocol cohort for immunogenicity at Day 164 included subjects who had not received a vaccine not specified in the protocol during the primary vaccination course, for whom 3 doses were administered and assay results were available for antibodies against H1N1 antigen at day 21 after the second H1N1 vaccine dose (Day 164).

VRR for microneutralization titers was defined as the incidence rate of vaccinees with at least a 4-fold increase in post vaccination reciprocal titer relative to Day 0. The cut-off value for microneutralization titers is 1:28.

The According-To-Protocol cohort for immunogenicity at Day 164 included subjects who had not received a vaccine not specified in the protocol during the primary vaccination course, for whom 3 doses were administered and assay results were available for antibodies against H1N1 antigen at day 21 after the second H1N1 vaccine dose (Day 164).

A seropositive subject was a subject whose HI antibody titer was greater than or equal to the assay cut-off value of 1:10.

The According-To-Protocol cohort for immunogenicity at Day 304 included subjects who had not received a vaccine not specified in the protocol during the primary vaccination course, for whom 3 doses were administered and assay results were available for antibodies against H1N1 antigen for blood sample taken at Day 304.

Titers were expressed as geometric mean antibody titers (GMTs).

The According-To-Protocol cohort for immunogenicity at Day 304 included subjects who had not received a vaccine not specified in the protocol during the primary vaccination course, for whom 3 doses were administered and assay results were available for antibodies against H1N1 antigen for blood sample taken at Day 304.

VRR for microneutralization titers was defined as the incidence rate of vaccinees with at least a 4-fold increase in post vaccination reciprocal titer relative to Day 0. The cut-off value for microneutralization titers is 1:28.

The According-To-Protocol cohort for immunogenicity at Day 304 included subjects who had not received a vaccine not specified in the protocol during the primary vaccination course, for whom 3 doses were administered and assay results were available for antibodies against H1N1 antigen at Day 304.

A seropositive subject was a subject whose HI antibody titer was greater than or equal to the assay cut-off value of 1:10.

The According-To-Protocol cohort for immunogenicity at Day 304 included subjects who had not received a vaccine not specified in the protocol during the primary vaccination course, for whom 3 doses were administered and assay results were available for antibodies against H1N1 antigen for blood sample taken at Day 304.

Titers were expressed as geometric mean antibody titers (GMTs).

The According-To-Protocol cohort for immunogenicity at Day 304 included subjects who had not received a vaccine not specified in the protocol during the primary vaccination course, for whom 3 doses were administered and assay results were available for antibodies against H1N1 antigen for blood sample taken at Day 304.

VRR for microneutralization titers was defined as the incidence rate of vaccinees with at least a 4-fold increase in post vaccination reciprocal titer relative to Day 0. The cut-off value for microneutralization titers is 1:28.

The According-To-Protocol cohort for immunogenicity at Day 304 included subjects who had not received a vaccine not specified in the protocol during the primary vaccination course, for whom 3 doses were administered and assay results were available for antibodies against H1N1 antigen at Day 304.

CD4 T cell-mediated immune responses against the antigens A/California/7/2009, A/Brisbane/59/2007 and A/Uruguay/716/2007 were analyzed for cells expressing at least 2 of the following immune markers: CD40 Ligand, Interleukin-2, Tumor Necrosis Factor alpha or Interferon-gamma.

The frequency was presented as number of cytokine-producing CD4+ cells per million CD4+ cells. All doubles= T cell expressing at least 2 cytokines.

Subjects with missing results were not included.

The ATP cohort for immunogenicity at Day 164 included subjects who received protocol specified vaccine(s) during the primary vaccination course, for whom 3 doses were administered and assay results were available for antibodies against H1N1 antigen at day 21 after second H1N1 vaccine dose (Day 164). Subjects with missing results were not included.

CD4 T cell-mediated immune responses against the antigens A/California/7/2009, A/Brisbane/59/2007 and A/Uruguay/716/2007 were analyzed for cells expressing at least 2 of the following immune markers: CD40 Ligand, Interleukin2, Tumor Necrosis Factor alpha or Interferongamma. The frequency was presented as number of cytokineproducing CD4+ cells per million CD4+ cells. All doubles= T cell expressing at least 2 cytokines.

The According-To-Protocol cohort for immunogenicity at Day 304 included all evaluable subjects who had not received a vaccine not specified or forbidden in the protocol during the primary vaccination course, for whom 3 doses were administered and assay results were available for antibodies against H1N1 antigen for the blood sample taken at Day 304.

pIMDs are a subset of adverse events (AEs) that include both clearly autoimmune diseases and also other inflammatory and/or neurologic disorders which may or may not have an autoimmune etiology. Related = symptom assed by the investigator as causally related to the study vaccination.

MAEs refer to events that required medical attention defined as hospitalization, an emergency room visit or a visit to or from medical personnel (medical doctor) for any reason. Related = symptom assed by the investigator as causally related to the study vaccination.

An unsolicited adverse event is any adverse event (i.e. 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) reported in addition to those solicited during the clinical study and any solicited symptom with onset outside the specified period of follow-up for solicited symptoms.

Unsolicited AEs were collected after the administration of the Flulaval vaccine or the placebo dose and the data has been pooled based on the vaccination received at Day 0.

The Total Vaccinated cohort included all vaccinated subjects for whom data were available.

Unsolicited AEs were collected after the administration of the Arepanrix or the unadjuvanted formulation of Arepanrix vaccine.

An unsolicited adverse event is any adverse event (i.e. 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) reported in addition to those solicited during the clinical study and any solicited symptom with onset outside the specified period of follow-up for solicited symptoms.

The Total Vaccinated cohort included all vaccinated subjects for whom data were available.

SAEs assessed include medical occurrences that results in death, are life threatening, require hospitalization or prolongation of hospitalization, results in disability/incapacity or are a congenital anomaly/birth defect in the offspring of a study subjects. Related = symptom assed by the investigator as causally related to the study vaccination.

SAEs assessed include medical occurrences that results in death, are life threatening, require hospitalization or prolongation of hospitalization, results in disability/incapacity or are a congenital anomaly/birth defect in the offspring of a study subjects. Related = symptom assed by the investigator as causally related to the study vaccination. Missing values will be added once they become available.

The Total Vaccinated cohort included all vaccinated subjects for whom data were available.

MAEs refer to events that required medical attention defined as hospitalization, an emergency room visit or a visit to or from medical personnel (medical doctor) for any reason. Related = symptom assed by the investigator as causally related to the study vaccination.

The Total Vaccinated cohort included all vaccinated subjects for whom data were available.

pIMDs are a subset of adverse events (AEs) that include both clearly autoimmune diseases and also other inflammatory and/or neurologic disorders which may or may not have an autoimmune etiology. Related = symptom assed by the investigator as causally related to the study vaccination.

The Total Vaccinated cohort included all vaccinated subjects for whom data were available.

Solicited local symptoms assessed were pain, redness and swelling and data collected was pooled by administration of vaccination received at Day 0 (i.e. Flulaval or Saline placebo).

Any was defined as any solicited local symptom reported irrespective of intensity. Grade 3 pain was defined as pain that prevented normal activity. Grade 3 redness and swelling were defined as redness/swelling above 100 millimeter (mm).

The Total Vaccinated cohort included all vaccinated subjects for whom data were available.

Solicited general symptoms assessed were fatigue, headache, joint pain at other location, muscle aches, shivering, sweating and temperature (= axillary temperature equal to or above 38.0 degrees Celsius (°C)) and data collected was pooled by administration of vaccination received at Day 0 (i.e. Flulaval or Saline placebo).

Any = any solicited general symptom reported irrespective of intensity and relationship to vaccination. Related = symptoms considered by the investigator to have a causal relationship to vaccination. Grade 3 symptoms = symptoms that prevented normal activity. Grade 3 fever = axillary temperature above 39.0°C.

The Total Vaccinated cohort included all vaccinated subjects for whom data were available.

Solicited local symptoms assessed were pain, redness and swelling and were collected after the administration of the Arepanrix or the unadjuvanted formulation of Arepanrix vaccine.

Any was defined as any solicited local symptom reported irrespective of intensity. Grade 3 pain was defined as pain that prevented normal activity. Grade 3 redness and swelling were defined as redness/swelling above 100 millimeter (mm).

The Total Vaccinated cohort included all vaccinated subjects for whom data were available.

Solicited general symptoms assessed were fatigue, headache, joint pain at other location, muscle aches, shivering, sweating and temperature (= axillary temperature equal to or above 38.0 degrees Celsius (°C)) and were collected after the administration of the Arepanrix or the unadjuvanted formulation of Arepanrix vaccine.

Any = any solicited general symptom reported irrespective of intensity and relationship to vaccination. Related = symptoms considered by the investigator to have a causal relationship to vaccination. Grade 3 symptoms = symptoms that prevented normal activity. Grade 3 fever = axillary temperature above 39.0°C.

The Total Vaccinated cohort included all vaccinated subjects for whom data were available.

Laboratory parameters assessed were white blood cells (WBC), neutrophils (NEU), lymphocytes (LYM), monocytes (MON), eosinophils (EOS), basophils (BAS), red blood cells (RBC), hemoglobin (Hgb), hematocrit (Hct) and platelets (PLA). For each parameter and for each status at baseline it was assessed whether the post-vaccination values of the parameter were above, below or within the range (unkown values are also indicated).

The Total Vaccinated cohort included all vaccinated subjects for whom data were available.

Laboratory parameters assessed were alanine aminotransferase (ALAT), aspartate aminotransferase (ASAT), alkaline phosphatise (AP), creatinine (CREA), blood urea nitrogen (BUN) and bilirubin (BIL) (total (T) and direct (D)).

For each parameter and for each status at baseline it was assessed whether the post-vaccination values of the parameter were above, below or within the range (unkown values are also indicated).

The Total Vaccinated cohort included all vaccinated subjects for whom data were available.

Laboratory parameters assessed were white blood cells (WBC), neutrophils (NEU), lymphocytes (LYM), monocytes (MON), eosinophils (EOS), basophils (BAS), red blood cells (RBC), hemoglobin (Hgb), hematocrit (Hct) and platelets (PLA). For each parameter and for each status at baseline it was assessed whether the post-vaccination values of the parameter were above, below or within the range (unkown values are also indicated).

The Total Vaccinated cohort included all vaccinated subjects for whom data were available.

N (Number of participants analyzed)= number of subjects with laboratory results for the specified visit and laboratory parameter in a given baseline category Thus, there are subjects with missing results which have not been mentioned here.

Laboratory parameters assessed were alanine aminotransferase (ALAT), aspartate aminotransferase (ASAT), alkaline phosphatase (AP), creatinine (CREA), blood urea nitrogen (BUN), and bilirubin (BIL) (total (T) and direct (D)). For each parameter and for each status at baseline it was assessed whether the post-vaccination values of the parameter were above, below or within the range (unkown values are also indicated).

The Total Vaccinated cohort included all vaccinated subjects for whom data were available

N (Number of participants analyzed)= number of subjects with laboratory results for the specified visit and laboratory parameter in a given baseline category Thus, there are subjects with missing results which have not been mentioned here.

A seropositive subject was a subject whose HI antibody titer was greater than or equal to the assay cut-off value of 1:10.

Seropositivity rates of H1N1 HI antibody titers in terms of humoral immune response was pooled by the vaccination received at Day 0 (i.e. Flulaval or Saline placebo) at Days 7, 14 and 21 upto the administration of the first dose of Arepanrix or the unadjuvanted formulation of Arepanrix vaccine.

The According-To-Protocol cohort for immunogenicity at Day 164 included subjects who had not received a vaccine not specified in the protocol during the primary vaccination course, for whom 3 doses were administered and assay results were available for antibodies against H1N1 antigen at day 21 after the second H1N1 vaccine dose (Day 164).

Titers were expressed as geometric mean antibody titers (GMTs). GMTs of H1N1 HI antibody titers in terms of humoral immune response was pooled by the vaccination received at Day 0 (i.e. Flulaval or Saline placebo) at Days 7, 14, 21 and 122 upto the administration of the first dose of Arepanrix or the unadjuvanted formulation of Arepanrix vaccine.

The According-To-Protocol cohort for immunogenicity at Day 164 included subjects who had not received a vaccine not specified in the protocol during the primary vaccination course, for whom 3 doses were administered and assay results were available for antibodies against H1N1 antigen at day 21 after the second H1N1 vaccine dose (Day 164).

A seropositive subject was a subject whose HI antibody titer was greater than or equal to the assay cut-off value of 1:10.

The According-To-Protocol cohort for immunogenicity at Day 164 included subjects who had not received a vaccine not specified in the protocol during the primary vaccination course, for whom 3 doses were administered and assay results were available for antibodies against H1N1 antigen at day 21 after the second H1N1 vaccine dose (Day 164).

Titers were expressed as geometric mean antibody titers (GMTs).

The According-To-Protocol cohort for immunogenicity at Day 164 included subjects who had not received a vaccine not specified in the protocol during the primary vaccination course, for whom 3 doses were administered and assay results were available for antibodies against H1N1 antigen at day 21 after the second H1N1 vaccine dose (Day 164).

A seropositive subject was a subject whose HI antibody titer was greater than or equal to the assay cut-off value of 1:10.

Seropositivity rates of H1N1 HI antibody titers in terms of humoral immune response was pooled by the vaccination received at Day 0 (i.e. Flulaval or Saline placebo) at Days 7, 14, 21 and 122 upto the administration of the first dose of Arepanrix or the unadjuvanted formulation of Arepanrix vaccine.

The According-To-Protocol cohort for immunogenicity at Day 164 included subjects who had not received a vaccine not specified in the protocol during the primary vaccination course, for whom 3 doses were administered and assay results were available for antibodies against H1N1 antigen at day 21 after the second H1N1 vaccine dose (Day 164).

Titers were expressed as geometric mean antibody titers (GMTs). GMTs of H1N1 HI antibody titers in terms of humoral immune response was pooled by the vaccination received at Day 0 (i.e. Flulaval or Saline placebo) at Days 7, 14, 21 and 122 upto the administration of the first dose of Arepanrix or the unadjuvanted formulation of Arepanrix vaccine.

The According-To-Protocol cohort for immunogenicity at Day 164 included subjects who had not received a vaccine not specified in the protocol during the primary vaccination course, for whom 3 doses were administered and assay results were available for antibodies against H1N1 antigen at day 21 after the second H1N1 vaccine dose (Day 164).

A seropositive subject was a subject whose HI antibody titer was greater than or equal to the assay cut-off value of 1:10.

The According-To-Protocol cohort for immunogenicity at Day 164 included subjects who had not received a vaccine not specified in the protocol during the primary vaccination course, for whom 3 doses were administered and assay results were available for antibodies against H1N1 antigen at day 21 after the second H1N1 vaccine dose (Day 164).

Titers were expressed as geometric mean antibody titers (GMTs).

The According-To-Protocol cohort for immunogenicity at Day 164 included subjects who had not received a vaccine not specified in the protocol during the primary vaccination course, for whom 3 doses were administered and assay results were available for antibodies against H1N1 antigen at day 21 after the second H1N1 vaccine dose (Day 164).