Clinical Study to Evaluate the Safety, Immunogenicity and Efficacy of Investigational Flu Vaccine Compared to Approved Flu Vaccine in Children.

Relative efficacy of aQIV compared to non-adjuvanted comparator (TIV/QIV) was determined by the number of subjects ≥6 to <72 months of age with RT-PCR confirmed occurrence of influenza A and/or B of any influenza strain that occurred at ≥21 days and ≤180 days after the last vaccination or until the end of the influenza season, whichever was longer. Efficacy was determined on influenza cases caused by any of the influenza strains related to the two A subtypes and the B lineage(s) common to aQIV and TIV (i.e. A/H1N1, A/H3N2 and B/Yamagata during first influenza season), and common to aQIV and QIV (i.e. A/H1N1, A/H3N2 and both B lineages during second season and through the end of the trial).

Relative efficacy of aQIV compared to non-adjuvanted comparator (TIV/QIV) was determined by the number of subjects with RT-PCR confirmed occurrence of influenza A and/or B of any influenza strain that occurred at ≥21 days and ≤180 days after the last vaccination or until the end of the influenza season, whichever was longer. Efficacy was determined on influenza cases caused by any of the influenza strains related to the two A subtypes and the B lineage(s) common to aQIV and TIV (i.e. A/H1N1, A/H3N2 and B/Yamagata during first influenza season), and common to aQIV and QIV (i.e. A/H1N1, A/H3N2 and both B lineages during second season and through the end of the trial).

Relative efficacy of aQIV compared to non-adjuvanted comparator (TIV/QIV) was determined by the number of subjects with culture confirmed occurrence of influenza A and/or B of any influenza strain that occurred at ≥21 days and ≤180 days after the last vaccination or until the end of the influenza season, whichever was longer. Efficacy was determined on influenza cases caused by any of the influenza strains related to the two A subtypes and the B lineage(s) common to aQIV and TIV (i.e. A/H1N1, A/H3N2 and B/Yamagata during first influenza season), and common to aQIV and QIV (i.e. A/H1N1, A/H3N2 and both B lineages during second season and through the end of the trial).

Relative efficacy of aQIV compared to non-adjuvanted comparator (TIV/QIV) was determined by the number of subjects ≥6 to <72 months of age with RT-PCR confirmed and culture confirmed occurrence of influenza A and/or B of any influenza strain that occurred at ≥21 days and ≤180 days after the last vaccination or until the end of the influenza season, whichever was longer, in healthy subjects and subjects at risk of influenza related complications. Efficacy was determined on influenza cases caused by any of the influenza strains related to the two A subtypes and the B lineage(s) common to aQIV and TIV (i.e. A/H1N1, A/H3N2 and B/Yamagata during first influenza season), and common to aQIV and QIV (i.e. A/H1N1, A/H3N2 and both B lineages during second season and through the end of the trial).

Relative efficacy of aQIV compared to non-adjuvanted comparator (TIV/QIV) was determined by the number of subjects with RT-PCR confirmed occurrence of influenza A and/or B of any influenza strain that occurred at ≥21 days and ≤180 days after the last vaccination or until the end of the influenza season, whichever was longer. Efficacy was determined on influenza cases caused by any of the influenza strains related to the two A subtypes and the B lineage(s) common to aQIV and TIV (i.e. A/H1N1, A/H3N2 and B/Yamagata during first influenza season), and common to aQIV and QIV (i.e. A/H1N1, A/H3N2 and both B lineages during second season and through the end of the trial).

Relative efficacy of aQIV compared to non-adjuvanted comparator (TIV/QIV) was based on the number of vaccine naive subjects ≥6 to <72 months of age with RT-PCR confirmed occurrence of influenza A and/or B of any influenza strain that occurred at ≥7 days and ≥14 days after the first vaccination up to the day of the second vaccination. TIV was used as the comparator in Season 1; and QIV was used as the comparator in Season 2. Efficacy was determined on influenza cases caused by any of the influenza strains related to the two A subtypes and the B lineage(s) common to aQIV and TIV (i.e. A/H1N1, A/H3N2 and B/Yamagata during first influenza season), and common to aQIV and QIV (i.e. A/H1N1, A/H3N2 and both B lineages during second season and through the end of the trial).

Relative efficacy of aQIV compared to non-adjuvanted comparator (TIV/QIV) was based on the number of vaccine naïve subjects ≥6 to <72 months of age with RT-PCR confirmed occurrence of influenza A and/or B of any influenza strain that occurred at ≥7 days and ≤21 after the last vaccination. TIV was used as the comparator in Season 1; and QIV was used as the comparator in Season 2. Efficacy was determined on influenza cases caused by any of the influenza strains related to the two A subtypes and the B lineage(s) common to aQIV and TIV (i.e. A/H1N1, A/H3N2 and B/Yamagata during first influenza season), and common to aQIV and QIV (i.e. A/H1N1, A/H3N2 and both B lineages during second season and through the end of the trial).

Pooled GMT values across both naïve and non-naïve subjects are provided for the Day 22/50 (ie, 21 days after last vaccination) and Day 181/209 (ie, 180 days after last vaccination) assessments; Nonadjuvanted TIV administered in Season 1 and nonadjuvanted QIV administered in Season 2; Homologous strains: A/H1N1=A/California/7/2009 pdm09-like virus, A/H3N2=A/Texas/50/2012, B/ Yamagata=B/Massachusetts/2/2012 and B/Victoria=B/Brisbane/60/2008; For B/Victoria results from Season 2 only are presented for both vaccine groups and used in the vaccine comparison analysis.

GMTs for vaccine naïve subjects are provided by strain for Day 29 and Day 50; Nonadjuvanted TIV administered in Season 1 and nonadjuvanted QIV administered in Season 2; Homologous strains: A/H1N1=A/California/7/2009 pdm09-like virus, A/H3N2=A/Texas/50/2012, B/ Yamagata=B/Massachusetts/2/2012 and B/Victoria=B/Brisbane/60/2008; For B/Victoria results from Season 2 only are presented for both vaccine groups and used in the vaccine comparison analysis.

HI GMT was assessed on Day 1 and Day 50 for vaccine naïve healthy vs high risk subjects; and HI GMT were assessed on Day 1 and Day 22 for vaccine non-naïve healthy vs high risk subjects; pooled GMT values across both naïve and non-naïve subjects are provided for Day 22/50 (ie, 21 days after last vaccination) assessments.

The fold-increase in HI antibodies in response to vaccination was assessed as the GMR between all post-vaccination titers (ie, Day 29, 50, 209 for vaccine naïve subjects; Day 22, 181 for vaccine non-naïve subjects) and the baseline (Day 1) titer. Assessed GMRs thus correspond to Day 29/Day 1, Day 50/Day 1, and Day 209/Day 1 for vaccine naïve subjects and Day 22/Day 1 and Day 181/Day 1 for vaccine non-naïve subjects. Pooled GMR values across both naïve and non-naïve subjects are provided for Day (22/50)/Day 1 (ie, 21 days after last vaccination) and Day (181/209)/Day 1 (ie, 180 days after last vaccination); Nonadjuvanted TIV administered in Season 1 and nonadjuvanted QIV administered in Season 2; Homologous strains: A/H1N1=A/California/7/2009 pdm09-like virus, A/H3N2=A/Texas/50/2012, B/Yamagata=B/Massachusetts/2/2012 and B/Victoria=B/Brisbane/60/2008; For B/Victoria results from Season 2 only are presented for both vaccine groups and used in the vaccine comparison analysis.

SC rates were assessed on Day 1 and Day 50 (ie, 21 days after two vaccinations) for vaccine naïve subjects; and on Day 1 and Day 22 (ie, 21 days after one vaccination) for vaccine non-naïve subjects; values pooled across naive and non-naive subjects are provided. Seroconversion is defined as HI ≥ 1:40 for subjects negative at baseline (ie, HI titer<1:10); or a minimum 4-fold increase in HI titer for subjects positive at baseline (ie, HI titer ≥ 1:10); Nonadjuvanted TIV administered in Season 1 and nonadjuvanted QIV administered in Season 2; Homologous strain: A/H1N1=A/California/7/2009 pdm09-like virus, A/H3N2=A/Texas/50/2012, B/Yamagata=B/Massachusetts/2/2012 and B/Victoria=B/Brisbane/60/2008; For B/Victoria results from Season 2 only are presented for both vaccine groups and used in the vaccine.

comparison analysis (N=745 for aQIV, N=738 for comparator).

Antibody response was assessed as the percentage of subjects with HI titer of ≥1:40 at 180 days after last vaccination (ie, Day 209 for vaccine naïve subjects and Day 181 for vaccine non-naïve subjects). Results were then pooled across both vaccine naïve and non-naïve subjects. Homologous strains: A/H1N1=A/California/7/2009 pdm09-like virus, A/H3N2=A/Texas/50/2012, B/Yamagata=B/Massachusetts/2/2012 and B/Victoria=B/Brisbane/60/2008; B/Victoria results from Season 1 and Season 2 (aQIV) and Season 2 (comparator) are presented.

Antibody response was assessed as the percentage of subjects and differences of percentage of subjects with HI titers of ≥1:110, ≥1:151, ≥1:215, ≥1:330, and ≥1:629 at 21 days after last vaccination (ie, Day 50 for vaccine naïve subjects and Day 22 for vaccine non-naïve subjects). Results were then pooled across both vaccine naïve and non-naïve subjects. Homologous strains: A/H1N1=A/California/7/2009 pdm09-like virus, A/H3N2=A/Texas/50/2012, B/Yamagata=B/Massachusetts/2/2012 and B/Victoria=B/Brisbane/60/2008; B/Victoria results from Season 1 and Season 2 (aQIV) and Season 2 (comparator) are presented.

HI GMT was assessed 21 days after last vaccination (Day 50 for vaccine naïve subjects and Day 22 for vaccine non-naive subjects) pooled GMT values across both naïve and non-naïve subjects are provided for the Day 22/50 (ie, 21 days after last vaccination); Heterologous strains: H1N1=A/Brisbane/59/2007- like; H3N2 =A/Hong Kong/4801/2014; B/Yamagata=B/Phuket/3073/2013-like; B Victoria=B/Malaysia/2506/2004; For B/Victoria results from Season 2 only are presented for both vaccine groups.

SC rates were assessed on Day 50 (ie, 21 days after two vaccinations) for vaccine naïve subjects; and on Day 22 (ie, 21 days after one vaccination) for vaccine non-naïve subjects; values pooled across naive and non-naive subjects are provided. Seroconversion is defined as HI ≥ 1:40 for subjects negative at baseline (ie, HI titer<1:10); or a minimum 4-fold increase in HI titer for subjects positive at baseline (ie, HI titer ≥ 1:10); Heterologous strains include: H1N1=A/Brisbane/59/2007- like; H3N2 =A/Hong Kong/4801/2014; B/Yamagata=B/Phuket/3073/2013- like; B Victoria=B/Malaysia/2506/2004; For B/Victoria results from Season 2 only are presented for both vaccine groups

Antibody persistence was assessed as the percentage of subjects with HI titer of ≥1:40 at 21 days after last vaccination (ie, Day 50 for vaccine naïve subjects and Day 22 for vaccine non-naïve subjects). Results were then pooled across both vaccine naïve and non-naïve subjects; Heterologous strains: H1N1=A/Brisbane/59/2007- like; H3N2 =A/Hong Kong/4801/2014; B/Yamagata=B/Phuket/3073/2013- like; B Victoria=B/Malaysia/2506/2004; For B/Victoria results from Season 2 only are presented for both vaccine groups.

Subjects ≥6 to <72 months of age reporting solicited local and systemic reactions, day 1 to day 7 after vaccination with either aQIV or TIV/QIV.

Safety was assessed in terms of number of subjects ≥6 to <72 months of age reporting unsolicited reactions (Day 1 to Day 50 for vaccine naïve subjects and from Day 1 to Day 22 for vaccine non-naïve subjects); Serious Adverse Events (SAEs), AEs leading to New Onset of Chronic Diseases,(NOCD), Adverse Events of Special Interests (AESI), AEs leading to withdrawal from the study or study vaccination after vaccination with either aQIV or TIV/QIV were collected up to 12 months after last vaccination.