Trial Outcomes & Findings for Evaluate the Shedding and Immunogencity of Different Formulations of FluMist in Children 24 to <48 Months of Age (NCT NCT03143101)

Last Updated: 2018-12-11

Results Overview

Seroconversion rate is defined as at least (\>=) 4-fold rise from baseline in A/H1N1 HAI antibody titer. Percentage of participants with \>= 4-fold rise in A/H1N1 HAI antibody titer at Day 28 is reported. Comparative statistical analysis was planned only for 'FluMist Quadrivalent (2015-2016)' and 'FluMist Quadrivalent (2017-2018)' arms.

Recruitment status

COMPLETED

Study phase

PHASE4

Target enrollment

200 participants

Primary outcome timeframe

Day 28

Results posted on

2018-12-11

Participant Flow

The study was conducted from 08 May 2017 through 29 Sep 2017 in the USA.

A total of 200 participants were randomized and participated in the study.

Participant milestones

Participant milestones
Measure	FluMist Trivalent (2015-2016) Participants received intranasal spray of 0.2 milliliter (mL) (total dose in both nostrils) FluMist trivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 fluorescent focus units (FFU) of each vaccine strain. Strains included in the trivalent vaccine were: A/H1N1 (A/Bolivia/559/2013), A/H3N2 (A/Switzerland/9715293/2013), and B/Phuket/3073/2013 (B/Yamagata-lineage).	FluMist Quadrivalent (2015-2016) Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist quadrivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the vaccine were A/H1N1 (A/Bolivia/559/2013), A/H3N2 (A/Switzerland/9715293/2013), B/Phuket/3073/2013 (B/Yamagata-lineage), and B/Brisbane/60/2008 (B/Victoria-lineage).	FluMist Quadrivalent (2017-2018) Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist quadrivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the vaccine were the new A/H1N1 (A/Slovenia/2903/2015), A/H3N2 (A/New Caledonia/71/2014), B/Phuket/3073/2013 (B/Yamagata-lineage), and B/Brisbane/60/2008 (B/Victoria-lineage).
Overall Study STARTED	67	66	67
Overall Study COMPLETED	65	63	67
Overall Study NOT COMPLETED	2	3	0

Reasons for withdrawal

Reasons for withdrawal
Measure	FluMist Trivalent (2015-2016) Participants received intranasal spray of 0.2 milliliter (mL) (total dose in both nostrils) FluMist trivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 fluorescent focus units (FFU) of each vaccine strain. Strains included in the trivalent vaccine were: A/H1N1 (A/Bolivia/559/2013), A/H3N2 (A/Switzerland/9715293/2013), and B/Phuket/3073/2013 (B/Yamagata-lineage).	FluMist Quadrivalent (2015-2016) Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist quadrivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the vaccine were A/H1N1 (A/Bolivia/559/2013), A/H3N2 (A/Switzerland/9715293/2013), B/Phuket/3073/2013 (B/Yamagata-lineage), and B/Brisbane/60/2008 (B/Victoria-lineage).	FluMist Quadrivalent (2017-2018) Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist quadrivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the vaccine were the new A/H1N1 (A/Slovenia/2903/2015), A/H3N2 (A/New Caledonia/71/2014), B/Phuket/3073/2013 (B/Yamagata-lineage), and B/Brisbane/60/2008 (B/Victoria-lineage).
Overall Study Withdrawal by Subject	0	1	0
Overall Study Lost to Follow-up	2	2	0

Baseline Characteristics

As-treated population included all participants who received any investigational drug.

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	FluMist Trivalent (2015-2016) n=67 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist trivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the trivalent vaccine were: A/H1N1 (A/Bolivia/559/2013), A/H3N2 (A/Switzerland/9715293/2013), and B/Phuket/3073/2013 (B/Yamagata-lineage).	FluMist Quadrivalent (2015-2016) n=66 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist quadrivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the vaccine were A/H1N1 (A/Bolivia/559/2013), A/H3N2 (A/Switzerland/9715293/2013), B/Phuket/3073/2013 (B/Yamagata-lineage), and B/Brisbane/60/2008 (B/Victoria-lineage).	FluMist Quadrivalent (2017-2018) n=67 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist quadrivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the vaccine were the new A/H1N1 (A/Slovenia/2903/2015), A/H3N2 (A/New Caledonia/71/2014), B/Phuket/3073/2013 (B/Yamagata-lineage), and B/Brisbane/60/2008 (B/Victoria-lineage).	Total n=200 Participants Total of all reporting groups
Age, Continuous	35.96 months STANDARD_DEVIATION 6.41 • n=5 Participants • As-treated population included all participants who received any investigational drug.	34.96 months STANDARD_DEVIATION 6.78 • n=7 Participants • As-treated population included all participants who received any investigational drug.	34.94 months STANDARD_DEVIATION 6.80 • n=5 Participants • As-treated population included all participants who received any investigational drug.	35.29 months STANDARD_DEVIATION 6.65 • n=4 Participants • As-treated population included all participants who received any investigational drug.
Sex: Female, Male Female	27 Participants n=5 Participants • As-treated population included all participants who received any investigational drug.	32 Participants n=7 Participants • As-treated population included all participants who received any investigational drug.	35 Participants n=5 Participants • As-treated population included all participants who received any investigational drug.	94 Participants n=4 Participants • As-treated population included all participants who received any investigational drug.
Sex: Female, Male Male	40 Participants n=5 Participants • As-treated population included all participants who received any investigational drug.	34 Participants n=7 Participants • As-treated population included all participants who received any investigational drug.	32 Participants n=5 Participants • As-treated population included all participants who received any investigational drug.	106 Participants n=4 Participants • As-treated population included all participants who received any investigational drug.
Ethnicity (NIH/OMB) Hispanic or Latino	11 Participants n=5 Participants • As-treated population included all participants who received any investigational drug.	9 Participants n=7 Participants • As-treated population included all participants who received any investigational drug.	14 Participants n=5 Participants • As-treated population included all participants who received any investigational drug.	34 Participants n=4 Participants • As-treated population included all participants who received any investigational drug.
Ethnicity (NIH/OMB) Not Hispanic or Latino	56 Participants n=5 Participants • As-treated population included all participants who received any investigational drug.	57 Participants n=7 Participants • As-treated population included all participants who received any investigational drug.	53 Participants n=5 Participants • As-treated population included all participants who received any investigational drug.	166 Participants n=4 Participants • As-treated population included all participants who received any investigational drug.
Ethnicity (NIH/OMB) Unknown or Not Reported	0 Participants n=5 Participants • As-treated population included all participants who received any investigational drug.	0 Participants n=7 Participants • As-treated population included all participants who received any investigational drug.	0 Participants n=5 Participants • As-treated population included all participants who received any investigational drug.	0 Participants n=4 Participants • As-treated population included all participants who received any investigational drug.
Race (NIH/OMB) American Indian or Alaska Native	0 Participants n=5 Participants • As-treated population included all participants who received any investigational drug.	1 Participants n=7 Participants • As-treated population included all participants who received any investigational drug.	0 Participants n=5 Participants • As-treated population included all participants who received any investigational drug.	1 Participants n=4 Participants • As-treated population included all participants who received any investigational drug.
Race (NIH/OMB) Asian	1 Participants n=5 Participants • As-treated population included all participants who received any investigational drug.	0 Participants n=7 Participants • As-treated population included all participants who received any investigational drug.	0 Participants n=5 Participants • As-treated population included all participants who received any investigational drug.	1 Participants n=4 Participants • As-treated population included all participants who received any investigational drug.
Race (NIH/OMB) Native Hawaiian or Other Pacific Islander	2 Participants n=5 Participants • As-treated population included all participants who received any investigational drug.	0 Participants n=7 Participants • As-treated population included all participants who received any investigational drug.	1 Participants n=5 Participants • As-treated population included all participants who received any investigational drug.	3 Participants n=4 Participants • As-treated population included all participants who received any investigational drug.
Race (NIH/OMB) Black or African American	9 Participants n=5 Participants • As-treated population included all participants who received any investigational drug.	9 Participants n=7 Participants • As-treated population included all participants who received any investigational drug.	13 Participants n=5 Participants • As-treated population included all participants who received any investigational drug.	31 Participants n=4 Participants • As-treated population included all participants who received any investigational drug.
Race (NIH/OMB) White	52 Participants n=5 Participants • As-treated population included all participants who received any investigational drug.	55 Participants n=7 Participants • As-treated population included all participants who received any investigational drug.	49 Participants n=5 Participants • As-treated population included all participants who received any investigational drug.	156 Participants n=4 Participants • As-treated population included all participants who received any investigational drug.
Race (NIH/OMB) More than one race	3 Participants n=5 Participants • As-treated population included all participants who received any investigational drug.	1 Participants n=7 Participants • As-treated population included all participants who received any investigational drug.	3 Participants n=5 Participants • As-treated population included all participants who received any investigational drug.	7 Participants n=4 Participants • As-treated population included all participants who received any investigational drug.
Race (NIH/OMB) Unknown or Not Reported	0 Participants n=5 Participants • As-treated population included all participants who received any investigational drug.	0 Participants n=7 Participants • As-treated population included all participants who received any investigational drug.	1 Participants n=5 Participants • As-treated population included all participants who received any investigational drug.	1 Participants n=4 Participants • As-treated population included all participants who received any investigational drug.

PRIMARY outcome

Timeframe: Day 28

Population: Immunogenicity population included all participants in the as-treated population (ATP) who had no major protocol deviations judged to have the potential to interfere with the generation or interpretation of an immune response to investigational product. Here, "N" signifies number of participants analyzed for this outcome measure.

Outcome measures

Outcome measures
Measure	FluMist Trivalent (2015-2016) n=60 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist trivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the trivalent vaccine were: A/H1N1 (A/Bolivia/559/2013), A/H3N2 (A/Switzerland/9715293/2013), and B/Phuket/3073/2013 (B/Yamagata-lineage).	FluMist Quadrivalent (2015-2016) n=56 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist quadrivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the vaccine were A/H1N1 (A/Bolivia/559/2013), A/H3N2 (A/Switzerland/9715293/2013), B/Phuket/3073/2013 (B/Yamagata-lineage), and B/Brisbane/60/2008 (B/Victoria-lineage).	FluMist Quadrivalent (2017-2018) n=64 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist quadrivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the vaccine were the new A/H1N1 (A/Slovenia/2903/2015), A/H3N2 (A/New Caledonia/71/2014), B/Phuket/3073/2013 (B/Yamagata-lineage), and B/Brisbane/60/2008 (B/Victoria-lineage).
Percentage of Participants With A/H1N1 Hemagglutination Inhibition (HAI) Antibody Seroconversion Rate at Day 28	10.0 Percentage of participants Interval 3.8 to 20.5	5.4 Percentage of participants Interval 1.1 to 14.9	23.4 Percentage of participants Interval 13.8 to 35.7

PRIMARY outcome

Timeframe: Day 28

Population: Immunogenicity population included all participants in the ATP who had no major protocol deviations judged to have the potential to interfere with the generation or interpretation of an immune response to investigational product. Here, "N" signifies number of participants analyzed for this outcome measure.

Seroconversion rate is defined as \>= 4-fold rise from baseline in A/H3N2 HAI antibody titer. Percentage of participants with \>= 4-fold rise in A/H3N2 HAI antibody titer at Day 28 is reported.

Outcome measures

Outcome measures
Measure	FluMist Trivalent (2015-2016) n=60 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist trivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the trivalent vaccine were: A/H1N1 (A/Bolivia/559/2013), A/H3N2 (A/Switzerland/9715293/2013), and B/Phuket/3073/2013 (B/Yamagata-lineage).	FluMist Quadrivalent (2015-2016) n=56 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist quadrivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the vaccine were A/H1N1 (A/Bolivia/559/2013), A/H3N2 (A/Switzerland/9715293/2013), B/Phuket/3073/2013 (B/Yamagata-lineage), and B/Brisbane/60/2008 (B/Victoria-lineage).	FluMist Quadrivalent (2017-2018) n=64 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist quadrivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the vaccine were the new A/H1N1 (A/Slovenia/2903/2015), A/H3N2 (A/New Caledonia/71/2014), B/Phuket/3073/2013 (B/Yamagata-lineage), and B/Brisbane/60/2008 (B/Victoria-lineage).
Percentage of Participants With A/H3N2 HAI Antibody Seroconversion Rate at Day 28	51.7 Percentage of participants Interval 38.4 to 64.8	64.3 Percentage of participants Interval 50.4 to 76.6	31.3 Percentage of participants Interval 20.2 to 44.1

PRIMARY outcome

Timeframe: Day 28

Seroconversion rate is defined as \>= 4-fold rise from baseline in B/Yamagata HAI antibody titer. Percentage of participants with \>= 4-fold rise in B/Yamagata HAI antibody titer at Day 28 is reported.

Outcome measures

Outcome measures
Measure	FluMist Trivalent (2015-2016) n=60 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist trivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the trivalent vaccine were: A/H1N1 (A/Bolivia/559/2013), A/H3N2 (A/Switzerland/9715293/2013), and B/Phuket/3073/2013 (B/Yamagata-lineage).	FluMist Quadrivalent (2015-2016) n=56 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist quadrivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the vaccine were A/H1N1 (A/Bolivia/559/2013), A/H3N2 (A/Switzerland/9715293/2013), B/Phuket/3073/2013 (B/Yamagata-lineage), and B/Brisbane/60/2008 (B/Victoria-lineage).	FluMist Quadrivalent (2017-2018) n=64 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist quadrivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the vaccine were the new A/H1N1 (A/Slovenia/2903/2015), A/H3N2 (A/New Caledonia/71/2014), B/Phuket/3073/2013 (B/Yamagata-lineage), and B/Brisbane/60/2008 (B/Victoria-lineage).
Percentage of Participants With B/Yamagata HAI Antibody Seroconversion Rate at Day 28	50.0 Percentage of participants Interval 36.8 to 63.2	42.9 Percentage of participants Interval 29.7 to 56.8	57.8 Percentage of participants Interval 44.8 to 70.1

PRIMARY outcome

Timeframe: Day 28

Population: Immunogenicity population. B/Victoria strain was not included in the 'FluMist trivalent (2015-2016)' arm. Here, "N" signifies number of participants analyzed for this outcome measure.

Seroconversion rate is defined as \>= 4-fold rise from baseline in B/Victoria HAI antibody titer. Percentage of participants with \>= 4-fold rise in B/Victoria HAI antibody titer at Day 28 is reported.

Outcome measures

Outcome measures
Measure	FluMist Trivalent (2015-2016) Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist trivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the trivalent vaccine were: A/H1N1 (A/Bolivia/559/2013), A/H3N2 (A/Switzerland/9715293/2013), and B/Phuket/3073/2013 (B/Yamagata-lineage).	FluMist Quadrivalent (2015-2016) n=56 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist quadrivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the vaccine were A/H1N1 (A/Bolivia/559/2013), A/H3N2 (A/Switzerland/9715293/2013), B/Phuket/3073/2013 (B/Yamagata-lineage), and B/Brisbane/60/2008 (B/Victoria-lineage).	FluMist Quadrivalent (2017-2018) n=64 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist quadrivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the vaccine were the new A/H1N1 (A/Slovenia/2903/2015), A/H3N2 (A/New Caledonia/71/2014), B/Phuket/3073/2013 (B/Yamagata-lineage), and B/Brisbane/60/2008 (B/Victoria-lineage).
Percentage of Participants With B/Victoria HAI Antibody Seroconversion Rate at Day 28	—	14.3 Percentage of participants Interval 6.4 to 26.2	35.9 Percentage of participants Interval 24.3 to 48.9

PRIMARY outcome

Timeframe: Day 56

Seroconversion rate is defined as \>= 4-fold rise from baseline in A/H1N1 HAI antibody titer. Percentage of participants with \>= 4-fold rise in A/H1N1 HAI antibody titer at Day 56 is reported. Comparative statistical analysis was planned only for 'FluMist Quadrivalent (2015-2016)' and 'FluMist Quadrivalent (2017-2018)' arms.

Outcome measures

Outcome measures
Measure	FluMist Trivalent (2015-2016) n=59 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist trivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the trivalent vaccine were: A/H1N1 (A/Bolivia/559/2013), A/H3N2 (A/Switzerland/9715293/2013), and B/Phuket/3073/2013 (B/Yamagata-lineage).	FluMist Quadrivalent (2015-2016) n=56 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist quadrivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the vaccine were A/H1N1 (A/Bolivia/559/2013), A/H3N2 (A/Switzerland/9715293/2013), B/Phuket/3073/2013 (B/Yamagata-lineage), and B/Brisbane/60/2008 (B/Victoria-lineage).	FluMist Quadrivalent (2017-2018) n=62 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist quadrivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the vaccine were the new A/H1N1 (A/Slovenia/2903/2015), A/H3N2 (A/New Caledonia/71/2014), B/Phuket/3073/2013 (B/Yamagata-lineage), and B/Brisbane/60/2008 (B/Victoria-lineage).
Percentage of Participants With A/H1N1 HAI Antibody Seroconversion Rate at Day 56	23.7 Percentage of participants Interval 13.6 to 36.6	12.5 Percentage of participants Interval 5.2 to 24.1	45.2 Percentage of participants Interval 32.5 to 58.3

PRIMARY outcome

Timeframe: Day 56

Seroconversion rate is defined as \>= 4-fold rise from baseline in A/H3N2 HAI antibody titer. Percentage of participants with \>= 4-fold rise in A/H3N2 HAI antibody titer at Day 56 is reported.

Outcome measures

Outcome measures
Measure	FluMist Trivalent (2015-2016) n=59 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist trivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the trivalent vaccine were: A/H1N1 (A/Bolivia/559/2013), A/H3N2 (A/Switzerland/9715293/2013), and B/Phuket/3073/2013 (B/Yamagata-lineage).	FluMist Quadrivalent (2015-2016) n=56 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist quadrivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the vaccine were A/H1N1 (A/Bolivia/559/2013), A/H3N2 (A/Switzerland/9715293/2013), B/Phuket/3073/2013 (B/Yamagata-lineage), and B/Brisbane/60/2008 (B/Victoria-lineage).	FluMist Quadrivalent (2017-2018) n=62 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist quadrivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the vaccine were the new A/H1N1 (A/Slovenia/2903/2015), A/H3N2 (A/New Caledonia/71/2014), B/Phuket/3073/2013 (B/Yamagata-lineage), and B/Brisbane/60/2008 (B/Victoria-lineage).
Percentage of Participants With A/H3N2 HAI Antibody Seroconversion Rate at Day 56	54.2 Percentage of participants Interval 40.8 to 67.3	66.1 Percentage of participants Interval 52.2 to 78.2	40.3 Percentage of participants Interval 28.1 to 53.6

PRIMARY outcome

Timeframe: Day 56

Outcome measures

Outcome measures
Measure	FluMist Trivalent (2015-2016) n=60 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist trivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the trivalent vaccine were: A/H1N1 (A/Bolivia/559/2013), A/H3N2 (A/Switzerland/9715293/2013), and B/Phuket/3073/2013 (B/Yamagata-lineage).	FluMist Quadrivalent (2015-2016) n=56 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist quadrivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the vaccine were A/H1N1 (A/Bolivia/559/2013), A/H3N2 (A/Switzerland/9715293/2013), B/Phuket/3073/2013 (B/Yamagata-lineage), and B/Brisbane/60/2008 (B/Victoria-lineage).	FluMist Quadrivalent (2017-2018) n=62 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist quadrivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the vaccine were the new A/H1N1 (A/Slovenia/2903/2015), A/H3N2 (A/New Caledonia/71/2014), B/Phuket/3073/2013 (B/Yamagata-lineage), and B/Brisbane/60/2008 (B/Victoria-lineage).
Percentage of Participants With B/Yamagata HAI Antibody Seroconversion Rate at Day 56	50.0 Percentage of participants Interval 36.8 to 63.2	53.6 Percentage of participants Interval 39.7 to 67.0	54.8 Percentage of participants Interval 41.7 to 67.5

PRIMARY outcome

Timeframe: Day 56

Population: Immunogenicity population. B/Victoria strain was not included in the 'FluMist trivalent (2015-2016)' arm. Here, "N" signifies number of participants analyzed for this outcome measure.

Outcome measures

Outcome measures
Measure	FluMist Trivalent (2015-2016) Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist trivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the trivalent vaccine were: A/H1N1 (A/Bolivia/559/2013), A/H3N2 (A/Switzerland/9715293/2013), and B/Phuket/3073/2013 (B/Yamagata-lineage).	FluMist Quadrivalent (2015-2016) n=56 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist quadrivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the vaccine were A/H1N1 (A/Bolivia/559/2013), A/H3N2 (A/Switzerland/9715293/2013), B/Phuket/3073/2013 (B/Yamagata-lineage), and B/Brisbane/60/2008 (B/Victoria-lineage).	FluMist Quadrivalent (2017-2018) n=62 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist quadrivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the vaccine were the new A/H1N1 (A/Slovenia/2903/2015), A/H3N2 (A/New Caledonia/71/2014), B/Phuket/3073/2013 (B/Yamagata-lineage), and B/Brisbane/60/2008 (B/Victoria-lineage).
Percentage of Participants With B/Victoria HAI Antibody Seroconversion Rate at Day 56	—	25.0 Percentage of participants Interval 14.4 to 38.4	40.3 Percentage of participants Interval 28.1 to 53.6

SECONDARY outcome

Timeframe: Days 2, 3, 4, 5, and 7 after Dose 1 (Day 1 dose) and on Days 2, 4, and 6 after Dose 2 (Day 28 dose)

Population: Immunogenicity population. B/Victoria strain was not included in the 'FluMist trivalent (2015-2016)' arm.

Quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) was used to measure viral shedding from the nasopharyngeal swabs. Percentage of participants who shed virus are reported.

Outcome measures

Outcome measures
Measure	FluMist Trivalent (2015-2016) n=67 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist trivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the trivalent vaccine were: A/H1N1 (A/Bolivia/559/2013), A/H3N2 (A/Switzerland/9715293/2013), and B/Phuket/3073/2013 (B/Yamagata-lineage).	FluMist Quadrivalent (2015-2016) n=66 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist quadrivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the vaccine were A/H1N1 (A/Bolivia/559/2013), A/H3N2 (A/Switzerland/9715293/2013), B/Phuket/3073/2013 (B/Yamagata-lineage), and B/Brisbane/60/2008 (B/Victoria-lineage).	FluMist Quadrivalent (2017-2018) n=67 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist quadrivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the vaccine were the new A/H1N1 (A/Slovenia/2903/2015), A/H3N2 (A/New Caledonia/71/2014), B/Phuket/3073/2013 (B/Yamagata-lineage), and B/Brisbane/60/2008 (B/Victoria-lineage).
Percentage of Participants Who Shed Vaccine Virus by Formulation, Strain, Dose Number, and Baseline Serostatus as Measured by Quantitative Reverse Transcriptase Polymerase Chain Reaction (qRT-PCR) A/H1N1/HAI seronegative/Dose 1	86.7 Percentage of participants	81.4 Percentage of participants	94.9 Percentage of participants
Percentage of Participants Who Shed Vaccine Virus by Formulation, Strain, Dose Number, and Baseline Serostatus as Measured by Quantitative Reverse Transcriptase Polymerase Chain Reaction (qRT-PCR) A/H1N1/HAI seronegative/Dose 2	17.2 Percentage of participants	25.6 Percentage of participants	46.2 Percentage of participants
Percentage of Participants Who Shed Vaccine Virus by Formulation, Strain, Dose Number, and Baseline Serostatus as Measured by Quantitative Reverse Transcriptase Polymerase Chain Reaction (qRT-PCR) A/H1N1/HAI seropositive/Dose 1	86.1 Percentage of participants	63.6 Percentage of participants	71.4 Percentage of participants
Percentage of Participants Who Shed Vaccine Virus by Formulation, Strain, Dose Number, and Baseline Serostatus as Measured by Quantitative Reverse Transcriptase Polymerase Chain Reaction (qRT-PCR) A/H1N1/HAI seropositive/Dose 2	22.9 Percentage of participants	23.8 Percentage of participants	29.6 Percentage of participants
Percentage of Participants Who Shed Vaccine Virus by Formulation, Strain, Dose Number, and Baseline Serostatus as Measured by Quantitative Reverse Transcriptase Polymerase Chain Reaction (qRT-PCR) A/H3N2/HAI seronegative/Dose 1	100.0 Percentage of participants	100.0 Percentage of participants	95.8 Percentage of participants
Percentage of Participants Who Shed Vaccine Virus by Formulation, Strain, Dose Number, and Baseline Serostatus as Measured by Quantitative Reverse Transcriptase Polymerase Chain Reaction (qRT-PCR) A/H3N2/HAI seronegative/Dose 2	55.0 Percentage of participants	60.0 Percentage of participants	79.2 Percentage of participants
Percentage of Participants Who Shed Vaccine Virus by Formulation, Strain, Dose Number, and Baseline Serostatus as Measured by Quantitative Reverse Transcriptase Polymerase Chain Reaction (qRT-PCR) A/H3N2/HAI seropositive/Dose 1	95.6 Percentage of participants	83.3 Percentage of participants	95.3 Percentage of participants
Percentage of Participants Who Shed Vaccine Virus by Formulation, Strain, Dose Number, and Baseline Serostatus as Measured by Quantitative Reverse Transcriptase Polymerase Chain Reaction (qRT-PCR) A/H3N2/HAI seropositive/Dose 2	47.7 Percentage of participants	44.8 Percentage of participants	59.5 Percentage of participants
Percentage of Participants Who Shed Vaccine Virus by Formulation, Strain, Dose Number, and Baseline Serostatus as Measured by Quantitative Reverse Transcriptase Polymerase Chain Reaction (qRT-PCR) B/Yamagata/HAI seronegative/Dose 1	100.0 Percentage of participants	98.1 Percentage of participants	100.0 Percentage of participants
Percentage of Participants Who Shed Vaccine Virus by Formulation, Strain, Dose Number, and Baseline Serostatus as Measured by Quantitative Reverse Transcriptase Polymerase Chain Reaction (qRT-PCR) B/Yamagata/HAI seronegative/Dose 2	42.0 Percentage of participants	39.6 Percentage of participants	31.4 Percentage of participants
Percentage of Participants Who Shed Vaccine Virus by Formulation, Strain, Dose Number, and Baseline Serostatus as Measured by Quantitative Reverse Transcriptase Polymerase Chain Reaction (qRT-PCR) B/Yamagata/HAI seropositive/Dose 1	73.3 Percentage of participants	81.8 Percentage of participants	93.8 Percentage of participants
Percentage of Participants Who Shed Vaccine Virus by Formulation, Strain, Dose Number, and Baseline Serostatus as Measured by Quantitative Reverse Transcriptase Polymerase Chain Reaction (qRT-PCR) B/Yamagata/HAI seropositive/Dose 2	50.0 Percentage of participants	54.5 Percentage of participants	53.3 Percentage of participants
Percentage of Participants Who Shed Vaccine Virus by Formulation, Strain, Dose Number, and Baseline Serostatus as Measured by Quantitative Reverse Transcriptase Polymerase Chain Reaction (qRT-PCR) B/Victoria/HAI seronegative/Dose 1	—	100.0 Percentage of participants	100.0 Percentage of participants
Percentage of Participants Who Shed Vaccine Virus by Formulation, Strain, Dose Number, and Baseline Serostatus as Measured by Quantitative Reverse Transcriptase Polymerase Chain Reaction (qRT-PCR) B/Victoria/HAI seronegative/Dose 2	—	44.8 Percentage of participants	53.8 Percentage of participants
Percentage of Participants Who Shed Vaccine Virus by Formulation, Strain, Dose Number, and Baseline Serostatus as Measured by Quantitative Reverse Transcriptase Polymerase Chain Reaction (qRT-PCR) B/Victoria/HAI seropositive/Dose 1	—	83.3 Percentage of participants	100.0 Percentage of participants
Percentage of Participants Who Shed Vaccine Virus by Formulation, Strain, Dose Number, and Baseline Serostatus as Measured by Quantitative Reverse Transcriptase Polymerase Chain Reaction (qRT-PCR) B/Victoria/HAI seropositive/Dose 2	—	50.0 Percentage of participants	37.0 Percentage of participants

SECONDARY outcome

Timeframe: Days 2, 3, 4, 5, and 7 after Dose 1 (Day 1 dose) and on Days 2, 4 and 6 after Dose 2 (Day 28 dose)

Population: Participants included in immunogenicity population and who shed vaccine virus were analyzed for this outcome measure. B/Victoria strain was not included in the 'FluMist trivalent (2015-2016)' arm.

Quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) was used to measure viral shedding from the nasopharyngeal swabs. Number of days of virus shedding are reported.

Outcome measures

Outcome measures
Measure	FluMist Trivalent (2015-2016) n=66 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist trivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the trivalent vaccine were: A/H1N1 (A/Bolivia/559/2013), A/H3N2 (A/Switzerland/9715293/2013), and B/Phuket/3073/2013 (B/Yamagata-lineage).	FluMist Quadrivalent (2015-2016) n=65 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist quadrivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the vaccine were A/H1N1 (A/Bolivia/559/2013), A/H3N2 (A/Switzerland/9715293/2013), B/Phuket/3073/2013 (B/Yamagata-lineage), and B/Brisbane/60/2008 (B/Victoria-lineage).	FluMist Quadrivalent (2017-2018) n=67 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist quadrivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the vaccine were the new A/H1N1 (A/Slovenia/2903/2015), A/H3N2 (A/New Caledonia/71/2014), B/Phuket/3073/2013 (B/Yamagata-lineage), and B/Brisbane/60/2008 (B/Victoria-lineage).
Number of Days of Vaccine Virus Shedding by Formulation, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR A/H1N1/HAI seronegative/Dose 1	2.2 Days Standard Deviation 1.2	2.2 Days Standard Deviation 1.0	2.8 Days Standard Deviation 1.3
Number of Days of Vaccine Virus Shedding by Formulation, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR A/H1N1/HAI seronegative/Dose 2	1.2 Days Standard Deviation 0.4	1.4 Days Standard Deviation 0.7	1.3 Days Standard Deviation 0.5
Number of Days of Vaccine Virus Shedding by Formulation, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR A/H1N1/HAI seropositive/Dose 1	2.2 Days Standard Deviation 1.0	1.9 Days Standard Deviation 0.7	2.0 Days Standard Deviation 1.3
Number of Days of Vaccine Virus Shedding by Formulation, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR A/H1N1/HAI seropositive/Dose 2	1.1 Days Standard Deviation 0.4	1.0 Days Standard Deviation 0.0	1.1 Days Standard Deviation 0.4
Number of Days of Vaccine Virus Shedding by Formulation, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR A/H3N2/HAI seronegative/Dose 1	4.5 Days Standard Deviation 1.0	4.5 Days Standard Deviation 0.9	3.9 Days Standard Deviation 1.2
Number of Days of Vaccine Virus Shedding by Formulation, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR A/H3N2/HAI seronegative/Dose 2	1.3 Days Standard Deviation 0.6	1.1 Days Standard Deviation 0.4	1.7 Days Standard Deviation 0.8
Number of Days of Vaccine Virus Shedding by Formulation, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR A/H3N2/HAI seropositive/Dose 1	3.8 Days Standard Deviation 1.5	3.4 Days Standard Deviation 1.6	2.5 Days Standard Deviation 1.4
Number of Days of Vaccine Virus Shedding by Formulation, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR A/H3N2/HAI seropositive/Dose 2	1.3 Days Standard Deviation 0.6	1.5 Days Standard Deviation 0.8	1.4 Days Standard Deviation 0.6
Number of Days of Vaccine Virus Shedding by Formulation, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR B/Yamagata/HAI seronegative/Dose 1	3.6 Days Standard Deviation 1.3	3.6 Days Standard Deviation 1.3	4.0 Days Standard Deviation 1.1
Number of Days of Vaccine Virus Shedding by Formulation, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR B/Yamagata/HAI seronegative/Dose 2	1.3 Days Standard Deviation 0.6	1.3 Days Standard Deviation 0.7	1.1 Days Standard Deviation 0.3
Number of Days of Vaccine Virus Shedding by Formulation, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR B/Yamagata/HAI seropositive/Dose 1	2.5 Days Standard Deviation 1.2	3.3 Days Standard Deviation 1.0	3.1 Days Standard Deviation 1.6
Number of Days of Vaccine Virus Shedding by Formulation, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR B/Yamagata/HAI seropositive/Dose 2	1.1 Days Standard Deviation 0.4	1.0 Days Standard Deviation 0.0	1.3 Days Standard Deviation 0.5
Number of Days of Vaccine Virus Shedding by Formulation, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR B/Victoria/HAI seronegative/Dose 1	—	3.9 Days Standard Deviation 1.2	4.6 Days Standard Deviation 0.8
Number of Days of Vaccine Virus Shedding by Formulation, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR B/Victoria/HAI seronegative/Dose 2	—	1.4 Days Standard Deviation 0.6	1.4 Days Standard Deviation 0.6
Number of Days of Vaccine Virus Shedding by Formulation, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR B/Victoria/HAI seropositive/Dose 1	—	2.0 Days Standard Deviation 1.0	3.5 Days Standard Deviation 1.5
Number of Days of Vaccine Virus Shedding by Formulation, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR B/Victoria/HAI seropositive/Dose 2	—	1.0 Days Standard Deviation 0.0	1.1 Days Standard Deviation 0.3

SECONDARY outcome

Timeframe: Day (D) 2, D3, D4, D5, and D7 after Dose 1 (D1 dose) and on D2, D4 and D6 after Dose 2 (D28 dose)

Quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) was used to measure viral titer from the nasopharyngeal swabs. Viral titers are reported.

Outcome measures

SECONDARY outcome

Timeframe: Days 28 and 56

Population: Immunogenicity population. B/Victoria strain was not included in the 'FluMist trivalent (2015-2016)' arm.

Seroconversion rate is defined as \>= 4-fold rise from baseline in strain specific microneutralizing antibody titer. Baseline microneutralization values of less than or equal to (\<=) 10 were considered as microneutralization status negative and values greater than (\>) 10 were considered microneutralization positive. Percentage of participants with \>= 4-fold rise in strain specific neutralizing antibody titer at Days 28 and 56 are reported.

Outcome measures

Outcome measures
Measure	FluMist Trivalent (2015-2016) n=66 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist trivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the trivalent vaccine were: A/H1N1 (A/Bolivia/559/2013), A/H3N2 (A/Switzerland/9715293/2013), and B/Phuket/3073/2013 (B/Yamagata-lineage).	FluMist Quadrivalent (2015-2016) n=65 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist quadrivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the vaccine were A/H1N1 (A/Bolivia/559/2013), A/H3N2 (A/Switzerland/9715293/2013), B/Phuket/3073/2013 (B/Yamagata-lineage), and B/Brisbane/60/2008 (B/Victoria-lineage).	FluMist Quadrivalent (2017-2018) n=67 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist quadrivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the vaccine were the new A/H1N1 (A/Slovenia/2903/2015), A/H3N2 (A/New Caledonia/71/2014), B/Phuket/3073/2013 (B/Yamagata-lineage), and B/Brisbane/60/2008 (B/Victoria-lineage).
Percentage of Participants With Strain-specific Neutralizing Antibody Seroconversion Rates From Baseline Through Days 28 and 56 by Baseline Serostatus A/H3N2/Baseline serostatus:negative/Day 28	100.0 Percentage of participants Interval 76.8 to 100.0	100.0 Percentage of participants Interval 87.2 to 100.0	46.7 Percentage of participants Interval 21.3 to 73.4
Percentage of Participants With Strain-specific Neutralizing Antibody Seroconversion Rates From Baseline Through Days 28 and 56 by Baseline Serostatus A/H3N2/Baseline serostatus:negative/Day 56	93.8 Percentage of participants Interval 69.8 to 99.8	100.0 Percentage of participants Interval 86.8 to 100.0	84.6 Percentage of participants Interval 54.6 to 98.1
Percentage of Participants With Strain-specific Neutralizing Antibody Seroconversion Rates From Baseline Through Days 28 and 56 by Baseline Serostatus A/H1N1/Baseline serostatus:negative/Day 28	0.0 Percentage of participants Interval 0.0 to 36.9	10.0 Percentage of participants Interval 1.2 to 31.7	—
Percentage of Participants With Strain-specific Neutralizing Antibody Seroconversion Rates From Baseline Through Days 28 and 56 by Baseline Serostatus A/H1N1/Baseline serostatus:negative/Day 56	37.5 Percentage of participants Interval 8.5 to 75.5	25.0 Percentage of participants Interval 8.7 to 49.1	—
Percentage of Participants With Strain-specific Neutralizing Antibody Seroconversion Rates From Baseline Through Days 28 and 56 by Baseline Serostatus A/H1N1/Baseline serostatus:positive/Day 28	3.8 Percentage of participants Interval 0.5 to 13.2	2.8 Percentage of participants Interval 0.1 to 14.5	15.9 Percentage of participants Interval 7.9 to 27.3
Percentage of Participants With Strain-specific Neutralizing Antibody Seroconversion Rates From Baseline Through Days 28 and 56 by Baseline Serostatus A/H1N1/Baseline serostatus:positive/Day 56	11.8 Percentage of participants Interval 4.4 to 23.9	2.8 Percentage of participants Interval 0.1 to 14.5	31.7 Percentage of participants Interval 20.3 to 45.0
Percentage of Participants With Strain-specific Neutralizing Antibody Seroconversion Rates From Baseline Through Days 28 and 56 by Baseline Serostatus A/H3N2/Baseline serostatus:positive/Day 28	47.8 Percentage of participants Interval 32.9 to 63.1	34.5 Percentage of participants Interval 17.9 to 54.3	25.0 Percentage of participants Interval 13.6 to 39.6
Percentage of Participants With Strain-specific Neutralizing Antibody Seroconversion Rates From Baseline Through Days 28 and 56 by Baseline Serostatus A/H3N2/Baseline serostatus:positive/Day 56	44.2 Percentage of participants Interval 29.1 to 60.1	43.3 Percentage of participants Interval 25.5 to 62.6	14.9 Percentage of participants Interval 6.2 to 28.3
Percentage of Participants With Strain-specific Neutralizing Antibody Seroconversion Rates From Baseline Through Days 28 and 56 by Baseline Serostatus B/Yamagata/Baseline serostatus:negative/Day 28	59.1 Percentage of participants Interval 43.2 to 73.7	45.7 Percentage of participants Interval 30.9 to 61.0	58.0 Percentage of participants Interval 43.2 to 71.8
Percentage of Participants With Strain-specific Neutralizing Antibody Seroconversion Rates From Baseline Through Days 28 and 56 by Baseline Serostatus B/Yamagata/Baseline serostatus:negative/Day 56	77.3 Percentage of participants Interval 62.2 to 88.5	68.1 Percentage of participants Interval 52.9 to 80.9	75.5 Percentage of participants Interval 61.1 to 86.7
Percentage of Participants With Strain-specific Neutralizing Antibody Seroconversion Rates From Baseline Through Days 28 and 56 by Baseline Serostatus B/Yamagata/Baseline serostatus:positive/Day 28	18.8 Percentage of participants Interval 4.0 to 45.6	0.0 Percentage of participants Interval 0.0 to 30.8	14.3 Percentage of participants Interval 1.8 to 42.8
Percentage of Participants With Strain-specific Neutralizing Antibody Seroconversion Rates From Baseline Through Days 28 and 56 by Baseline Serostatus B/Yamagata/Baseline serostatus:positive/Day 56	18.8 Percentage of participants Interval 4.0 to 45.6	0.0 Percentage of participants Interval 0.0 to 33.6	7.7 Percentage of participants Interval 0.2 to 36.0
Percentage of Participants With Strain-specific Neutralizing Antibody Seroconversion Rates From Baseline Through Days 28 and 56 by Baseline Serostatus B/Victoria/Baseline serostatus:negative/Day 28	—	20.8 Percentage of participants Interval 10.5 to 35.0	18.9 Percentage of participants Interval 9.4 to 32.0
Percentage of Participants With Strain-specific Neutralizing Antibody Seroconversion Rates From Baseline Through Days 28 and 56 by Baseline Serostatus B/Victoria/Baseline serostatus:negative/Day 56	—	16.3 Percentage of participants Interval 7.3 to 29.7	23.5 Percentage of participants Interval 12.8 to 37.5
Percentage of Participants With Strain-specific Neutralizing Antibody Seroconversion Rates From Baseline Through Days 28 and 56 by Baseline Serostatus B/Victoria/Baseline serostatus:positive/Day 28	—	12.5 Percentage of participants Interval 0.3 to 52.7	10.0 Percentage of participants Interval 0.3 to 44.5
Percentage of Participants With Strain-specific Neutralizing Antibody Seroconversion Rates From Baseline Through Days 28 and 56 by Baseline Serostatus B/Victoria/Baseline serostatus:positive/Day 56	—	14.3 Percentage of participants Interval 0.4 to 57.9	11.1 Percentage of participants Interval 0.3 to 48.2

SECONDARY outcome

Timeframe: Days 28 and 56

Population: Immunogenicity population. B/Victoria strain was not included in the 'FluMist trivalent (2015-2016)' arm.

Seroconversion rate is defined as \>= 2-fold rise from baseline in strain speciific nasal IgA antibody titer. Percentage of participants with \>= 2-fold rise in strain speciific nasal IgA antibody titer at Days 28 and 56 are reported for this outcome.

Outcome measures

Outcome measures
Measure	FluMist Trivalent (2015-2016) n=66 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist trivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the trivalent vaccine were: A/H1N1 (A/Bolivia/559/2013), A/H3N2 (A/Switzerland/9715293/2013), and B/Phuket/3073/2013 (B/Yamagata-lineage).	FluMist Quadrivalent (2015-2016) n=65 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist quadrivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the vaccine were A/H1N1 (A/Bolivia/559/2013), A/H3N2 (A/Switzerland/9715293/2013), B/Phuket/3073/2013 (B/Yamagata-lineage), and B/Brisbane/60/2008 (B/Victoria-lineage).	FluMist Quadrivalent (2017-2018) n=67 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist quadrivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the vaccine were the new A/H1N1 (A/Slovenia/2903/2015), A/H3N2 (A/New Caledonia/71/2014), B/Phuket/3073/2013 (B/Yamagata-lineage), and B/Brisbane/60/2008 (B/Victoria-lineage).
Percentage of Participants With Strain-specific Nasal Immunoglobulin A (IgA) Seroconversion Rate From Baseline Through Days 28 and 56 B/Yamagata//Day 28	69.8 Percentage of participants Interval 57.0 to 80.8	79.4 Percentage of participants Interval 67.3 to 88.5	77.6 Percentage of participants Interval 65.8 to 86.9
Percentage of Participants With Strain-specific Nasal Immunoglobulin A (IgA) Seroconversion Rate From Baseline Through Days 28 and 56 A/H1N1/Day 28	33.9 Percentage of participants Interval 22.3 to 47.0	31.7 Percentage of participants Interval 20.6 to 44.7	40.3 Percentage of participants Interval 28.5 to 53.0
Percentage of Participants With Strain-specific Nasal Immunoglobulin A (IgA) Seroconversion Rate From Baseline Through Days 28 and 56 A/H1N1//Day 56	40.6 Percentage of participants Interval 28.5 to 53.6	46.7 Percentage of participants Interval 33.7 to 60.0	67.7 Percentage of participants Interval 54.9 to 78.8
Percentage of Participants With Strain-specific Nasal Immunoglobulin A (IgA) Seroconversion Rate From Baseline Through Days 28 and 56 A/H3N2//Day 28	79.4 Percentage of participants Interval 67.3 to 88.5	79.0 Percentage of participants Interval 66.8 to 88.3	44.8 Percentage of participants Interval 32.6 to 57.4
Percentage of Participants With Strain-specific Nasal Immunoglobulin A (IgA) Seroconversion Rate From Baseline Through Days 28 and 56 A/H3N2/Day 56	89.1 Percentage of participants Interval 78.8 to 95.5	88.5 Percentage of participants Interval 77.8 to 95.3	55.4 Percentage of participants Interval 42.5 to 67.7
Percentage of Participants With Strain-specific Nasal Immunoglobulin A (IgA) Seroconversion Rate From Baseline Through Days 28 and 56 B/Yamagata//Day 56	81.3 Percentage of participants Interval 69.5 to 89.9	88.5 Percentage of participants Interval 77.8 to 95.3	86.4 Percentage of participants Interval 75.7 to 93.6
Percentage of Participants With Strain-specific Nasal Immunoglobulin A (IgA) Seroconversion Rate From Baseline Through Days 28 and 56 B/Victoria//Day 28	—	73.0 Percentage of participants Interval 60.3 to 83.4	79.1 Percentage of participants Interval 67.4 to 88.1
Percentage of Participants With Strain-specific Nasal Immunoglobulin A (IgA) Seroconversion Rate From Baseline Through Days 28 and 56 B/Victoria//Day 56	—	91.8 Percentage of participants Interval 81.9 to 97.3	84.8 Percentage of participants Interval 73.9 to 92.5

SECONDARY outcome

Timeframe: Days 28 and 56

Population: Immunogenicity population. B/Victoria strain was not included in the 'FluMist trivalent (2015-2016)' arm.

Strain specific antibody response defined as \>= 4-fold increase in HAI antibodies or \>= 4-fold increase in neutralizing antibodies or \>= 2-fold increase in IgA antibodies.

Outcome measures

Outcome measures
Measure	FluMist Trivalent (2015-2016) n=66 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist trivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the trivalent vaccine were: A/H1N1 (A/Bolivia/559/2013), A/H3N2 (A/Switzerland/9715293/2013), and B/Phuket/3073/2013 (B/Yamagata-lineage).	FluMist Quadrivalent (2015-2016) n=65 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist quadrivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the vaccine were A/H1N1 (A/Bolivia/559/2013), A/H3N2 (A/Switzerland/9715293/2013), B/Phuket/3073/2013 (B/Yamagata-lineage), and B/Brisbane/60/2008 (B/Victoria-lineage).	FluMist Quadrivalent (2017-2018) n=67 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist quadrivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the vaccine were the new A/H1N1 (A/Slovenia/2903/2015), A/H3N2 (A/New Caledonia/71/2014), B/Phuket/3073/2013 (B/Yamagata-lineage), and B/Brisbane/60/2008 (B/Victoria-lineage).
Percentage of Participants With Any Post Dose Strain-specific Antibody Response B/Victoria/Microneutralization response/Day 56	—	16.1 Percentage of participants	21.7 Percentage of participants
Percentage of Participants With Any Post Dose Strain-specific Antibody Response A/H1N1/HAI response/Day 28	10.0 Percentage of participants	5.4 Percentage of participants	23.4 Percentage of participants
Percentage of Participants With Any Post Dose Strain-specific Antibody Response A/H1N1/Microneutralization response/Day 28	3.3 Percentage of participants	5.4 Percentage of participants	15.9 Percentage of participants
Percentage of Participants With Any Post Dose Strain-specific Antibody Response A/H1N1/Nasal IgA response/Day 28	46.0 Percentage of participants	52.4 Percentage of participants	35.8 Percentage of participants
Percentage of Participants With Any Post Dose Strain-specific Antibody Response A/H1N1/HAI response/Day 56	23.7 Percentage of participants	12.5 Percentage of participants	45.2 Percentage of participants
Percentage of Participants With Any Post Dose Strain-specific Antibody Response A/H1N1/Microneutralization response/Day 56	15.3 Percentage of participants	10.7 Percentage of participants	31.7 Percentage of participants
Percentage of Participants With Any Post Dose Strain-specific Antibody Response A/H1N1/Nasal IgA response/Day 56	46.9 Percentage of participants	53.3 Percentage of participants	61.5 Percentage of participants
Percentage of Participants With Any Post Dose Strain-specific Antibody Response A/H3N2/HAI response/Day 28	51.7 Percentage of participants	64.3 Percentage of participants	31.3 Percentage of participants
Percentage of Participants With Any Post Dose Strain-specific Antibody Response A/H3N2/Microneutralization response/Day 28	60.0 Percentage of participants	66.1 Percentage of participants	30.2 Percentage of participants
Percentage of Participants With Any Post Dose Strain-specific Antibody Response A/H3N2/Nasal IgA response/Day 28	81.3 Percentage of participants	85.5 Percentage of participants	38.8 Percentage of participants
Percentage of Participants With Any Post Dose Strain-specific Antibody Response A/H3N2/HAI response/Day 56	54.2 Percentage of participants	66.1 Percentage of participants	40.3 Percentage of participants
Percentage of Participants With Any Post Dose Strain-specific Antibody Response A/H3N2/Microneutralization response/Day 56	57.6 Percentage of participants	69.6 Percentage of participants	30.0 Percentage of participants
Percentage of Participants With Any Post Dose Strain-specific Antibody Response A/H3N2/Nasal IgA response/Day 56	76.6 Percentage of participants	82.0 Percentage of participants	50.8 Percentage of participants
Percentage of Participants With Any Post Dose Strain-specific Antibody Response B/Yamagata/HAI response/Day 28	50.0 Percentage of participants	42.9 Percentage of participants	57.8 Percentage of participants
Percentage of Participants With Any Post Dose Strain-specific Antibody Response B/Yamagata/Microneutralization response/Day 28	48.3 Percentage of participants	37.5 Percentage of participants	48.4 Percentage of participants
Percentage of Participants With Any Post Dose Strain-specific Antibody Response B/Yamagata/Nasal IgA response/Day 28	65.6 Percentage of participants	87.3 Percentage of participants	61.2 Percentage of participants
Percentage of Participants With Any Post Dose Strain-specific Antibody Response B/Yamagata/HAI response/Day 56	50.0 Percentage of participants	53.6 Percentage of participants	54.8 Percentage of participants
Percentage of Participants With Any Post Dose Strain-specific Antibody Response B/Yamagata/Microneutralization response/Day 56	61.7 Percentage of participants	57.1 Percentage of participants	61.3 Percentage of participants
Percentage of Participants With Any Post Dose Strain-specific Antibody Response B/Yamagata/Nasal IgA response/Day 56	70.3 Percentage of participants	83.6 Percentage of participants	77.3 Percentage of participants
Percentage of Participants With Any Post Dose Strain-specific Antibody Response B/Victoria/HAI response/Day 28	—	14.3 Percentage of participants	35.9 Percentage of participants
Percentage of Participants With Any Post Dose Strain-specific Antibody Response B/Victoria/Microneutralization response/Day 28	—	19.6 Percentage of participants	17.5 Percentage of participants
Percentage of Participants With Any Post Dose Strain-specific Antibody Response B/Victoria/Nasal IgA response/Day 28	—	76.2 Percentage of participants	55.2 Percentage of participants
Percentage of Participants With Any Post Dose Strain-specific Antibody Response B/Victoria/HAI response/Day 56	—	25.0 Percentage of participants	40.3 Percentage of participants
Percentage of Participants With Any Post Dose Strain-specific Antibody Response B/Victoria/Nasal IgA response/Day 56	—	83.6 Percentage of participants	78.8 Percentage of participants

SECONDARY outcome

Timeframe: Day 1 through Day 14 after Dose 1 (Day 1 dose) and Dose 2 (Day 28 dose)

Population: ATP included all participants who received any investigational drug.

Solicited symptoms included fever by any route (temperature \>= 100.4 degrees Fahrenheit), runny/stuffy nose, sore throat, cough, headache, generalized muscle aches, lethargy or tiredness/weakness, and decreased appetite.

Outcome measures

Outcome measures
Measure	FluMist Trivalent (2015-2016) n=67 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist trivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the trivalent vaccine were: A/H1N1 (A/Bolivia/559/2013), A/H3N2 (A/Switzerland/9715293/2013), and B/Phuket/3073/2013 (B/Yamagata-lineage).	FluMist Quadrivalent (2015-2016) n=66 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist quadrivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the vaccine were A/H1N1 (A/Bolivia/559/2013), A/H3N2 (A/Switzerland/9715293/2013), B/Phuket/3073/2013 (B/Yamagata-lineage), and B/Brisbane/60/2008 (B/Victoria-lineage).	FluMist Quadrivalent (2017-2018) n=67 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist quadrivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the vaccine were the new A/H1N1 (A/Slovenia/2903/2015), A/H3N2 (A/New Caledonia/71/2014), B/Phuket/3073/2013 (B/Yamagata-lineage), and B/Brisbane/60/2008 (B/Victoria-lineage).
Percentage of Participants With Any Solicited Symptoms Cough: Dose 2	19.0 Percentage of participants	21.7 Percentage of participants	10.9 Percentage of participants
Percentage of Participants With Any Solicited Symptoms Decreased Appetite: Dose 1	13.4 Percentage of participants	12.3 Percentage of participants	11.9 Percentage of participants
Percentage of Participants With Any Solicited Symptoms Decreased Appetite: Dose 2	9.5 Percentage of participants	8.3 Percentage of participants	7.8 Percentage of participants
Percentage of Participants With Any Solicited Symptoms Fever: Dose 1	3.0 Percentage of participants	1.5 Percentage of participants	10.4 Percentage of participants
Percentage of Participants With Any Solicited Symptoms Fever: Dose 2	3.2 Percentage of participants	8.2 Percentage of participants	6.3 Percentage of participants
Percentage of Participants With Any Solicited Symptoms Runny/Stuffy Nose: Dose 1	34.3 Percentage of participants	41.5 Percentage of participants	43.3 Percentage of participants
Percentage of Participants With Any Solicited Symptoms Runny/Stuffy Nose: Dose 2	33.3 Percentage of participants	36.7 Percentage of participants	34.4 Percentage of participants
Percentage of Participants With Any Solicited Symptoms Sore Throat: Dose 1	6.0 Percentage of participants	1.5 Percentage of participants	4.5 Percentage of participants
Percentage of Participants With Any Solicited Symptoms Sore Throat: Dose 2	3.2 Percentage of participants	3.3 Percentage of participants	4.7 Percentage of participants
Percentage of Participants With Any Solicited Symptoms Cough: Dose 1	19.4 Percentage of participants	15.4 Percentage of participants	10.4 Percentage of participants
Percentage of Participants With Any Solicited Symptoms Headache: Dose 1	1.5 Percentage of participants	4.6 Percentage of participants	6.0 Percentage of participants
Percentage of Participants With Any Solicited Symptoms Headache: Dose 2	3.2 Percentage of participants	5.0 Percentage of participants	3.1 Percentage of participants
Percentage of Participants With Any Solicited Symptoms Generalized Muscle Aches: Dose 1	4.5 Percentage of participants	4.6 Percentage of participants	1.5 Percentage of participants
Percentage of Participants With Any Solicited Symptoms Generalized Muscle Aches: Dose 2	0.0 Percentage of participants	3.3 Percentage of participants	0.0 Percentage of participants
Percentage of Participants With Any Solicited Symptoms Lethargy/Tiredness/Weakness: Dose 1	13.4 Percentage of participants	13.8 Percentage of participants	16.4 Percentage of participants
Percentage of Participants With Any Solicited Symptoms Lethargy/Tiredness/Weakness: Dose 2	12.7 Percentage of participants	11.7 Percentage of participants	7.8 Percentage of participants

SECONDARY outcome

Timeframe: Day 1 through Day 28 after Dose 1 (Day 1 dose) and Dose 2 (Day 28 dose)

Population: ATP included all participants who received any investigational drug.

An Adverse Event (AE) is any unfavourable and unintended sign, symptoms, or diseases temporally associated with use of study drug, whether or not considered related to study drug. A serious adverse event (SAE) is an AE that results in death, initial or prolonged inpatient hospitalization, life-threatening, persistent or significant disability/incapacity, congenital anomaly/birth defect, or an important medical event. TEAEs and TESAEs are defined as AEs and SAEs present at baseline that worsened in intensity after administration of study drug, or events absent at baseline that emerged after administration of study drug.

Outcome measures

Outcome measures
Measure	FluMist Trivalent (2015-2016) n=67 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist trivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the trivalent vaccine were: A/H1N1 (A/Bolivia/559/2013), A/H3N2 (A/Switzerland/9715293/2013), and B/Phuket/3073/2013 (B/Yamagata-lineage).	FluMist Quadrivalent (2015-2016) n=66 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist quadrivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the vaccine were A/H1N1 (A/Bolivia/559/2013), A/H3N2 (A/Switzerland/9715293/2013), B/Phuket/3073/2013 (B/Yamagata-lineage), and B/Brisbane/60/2008 (B/Victoria-lineage).	FluMist Quadrivalent (2017-2018) n=67 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist quadrivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the vaccine were the new A/H1N1 (A/Slovenia/2903/2015), A/H3N2 (A/New Caledonia/71/2014), B/Phuket/3073/2013 (B/Yamagata-lineage), and B/Brisbane/60/2008 (B/Victoria-lineage).
Number of Participants With Treatment-emergent Adverse Events (TEAEs) and Treatment-emergent Serious Adverse Events (TESAEs) TEAEs	29 Participants	31 Participants	34 Participants
Number of Participants With Treatment-emergent Adverse Events (TEAEs) and Treatment-emergent Serious Adverse Events (TESAEs) TESAEs	0 Participants	0 Participants	0 Participants

Adverse Events

FluMist Trivalent (2015-2016)

Serious events: 0 serious events

Other events: 29 other events

Deaths: 0 deaths

FluMist Quadrivalent (2015-2016)

Serious events: 0 serious events

Other events: 31 other events

Deaths: 0 deaths

FluMist Quadrivalent (2017-2018)

Serious events: 0 serious events

Other events: 34 other events

Deaths: 0 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Additional Information

Raburn Mallory

MedImmune, LLC

Phone: +1-301-398-5799

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee MedImmune has 60 days to review results communications prior to public release and may delete information that compromises on-going studies or is considered proprietary. This restriction is not intended to compromise the objective scientific integrity of the manuscript, it being understood that results shall be published regardless of outcome.
Publication restrictions are in place

Restriction type: OTHER

Measure	FluMist Trivalent (2015-2016) n=66 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist trivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the trivalent vaccine were: A/H1N1 (A/Bolivia/559/2013), A/H3N2 (A/Switzerland/9715293/2013), and B/Phuket/3073/2013 (B/Yamagata-lineage).	FluMist Quadrivalent (2015-2016) n=65 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist quadrivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the vaccine were A/H1N1 (A/Bolivia/559/2013), A/H3N2 (A/Switzerland/9715293/2013), B/Phuket/3073/2013 (B/Yamagata-lineage), and B/Brisbane/60/2008 (B/Victoria-lineage).	FluMist Quadrivalent (2017-2018) n=67 Participants Participants received intranasal spray of 0.2 mL (total dose in both nostrils) FluMist quadrivalent vaccine on Days 1 and 28. Each 0.2 mL dose contained 10\^7±0.5 FFU of each vaccine strain. Strains included in the vaccine were the new A/H1N1 (A/Slovenia/2903/2015), A/H3N2 (A/New Caledonia/71/2014), B/Phuket/3073/2013 (B/Yamagata-lineage), and B/Brisbane/60/2008 (B/Victoria-lineage).
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR A/H3N2/HAI seropositive/Dose2D2	3.30 log10 viral particles/mL Standard Deviation 0.89	3.55 log10 viral particles/mL Standard Deviation 0.93	3.54 log10 viral particles/mL Standard Deviation 0.78
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR A/H3N2/HAI seropositive/Dose2D4	2.71 log10 viral particles/mL Standard Deviation 0.62	3.38 log10 viral particles/mL Standard Deviation 0.90	3.26 log10 viral particles/mL Standard Deviation 0.60
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR B/Yamagata/HAI seropositive/Dose1D4	3.46 log10 viral particles/mL Standard Deviation 0.04	4.60 log10 viral particles/mL Standard Deviation 1.44	4.94 log10 viral particles/mL Standard Deviation 1.28
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR B/Victoria/HAI seronegative/Dose1D3	—	4.12 log10 viral particles/mL Standard Deviation 1.02	4.39 log10 viral particles/mL Standard Deviation 0.98
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR B/Victoria/HAI seronegative/Dose1D4	—	4.02 log10 viral particles/mL Standard Deviation 1.13	4.58 log10 viral particles/mL Standard Deviation 1.24
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR A/H1N1/HAI seronegative/Dose1D2	3.79 log10 viral particles/mL Standard Deviation 0.56	3.76 log10 viral particles/mL Standard Deviation 0.71	3.70 log10 viral particles/mL Standard Deviation 0.49
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR A/H1N1/HAI seronegative/Dose1D3	3.66 log10 viral particles/mL Standard Deviation 0.55	3.81 log10 viral particles/mL Standard Deviation 0.83	4.21 log10 viral particles/mL Standard Deviation 0.97
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR A/H1N1/HAI seronegative/Dose1D4	3.63 log10 viral particles/mL Standard Deviation 0.34	3.34 log10 viral particles/mL Standard Deviation 0.56	3.81 log10 viral particles/mL Standard Deviation 0.94
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR A/H1N1/HAI seronegative/Dose1D5	3.12 log10 viral particles/mL Standard Deviation 0.16	3.17 log10 viral particles/mL Standard Deviation 0.10	3.85 log10 viral particles/mL Standard Deviation 0.48
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR A/H1N1/HAI seronegative/Dose1D7	3.17 log10 viral particles/mL Standard Deviation 0.40	—	2.93 log10 viral particles/mL Standard Deviation 0.23
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR A/H1N1/HAI seronegative/Dose2D2	3.68 log10 viral particles/mL Standard Deviation 0.88	3.29 log10 viral particles/mL Standard Deviation 0.30	3.90 log10 viral particles/mL Standard Deviation 1.04
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR A/H1N1/HAI seronegative/Dose2D4	—	3.49 log10 viral particles/mL Standard Deviation 0.37	4.02 log10 viral particles/mL Standard Deviation 1.24
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR A/H1N1/HAI seropositive/Dose1D2	3.66 log10 viral particles/mL Standard Deviation 0.46	3.48 log10 viral particles/mL Standard Deviation 0.62	3.14 log10 viral particles/mL Standard Deviation 0.45
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR A/H1N1/HAI seropositive/Dose1D3	3.39 log10 viral particles/mL Standard Deviation 0.57	4.03 log10 viral particles/mL Standard Deviation 0.91	3.99 log10 viral particles/mL Standard Deviation 0.84
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR A/H1N1/HAI seropositive/Dose1D4	3.09 log10 viral particles/mL Standard Deviation 0.62	3.39 log10 viral particles/mL Standard Deviation 0.25	3.97 log10 viral particles/mL Standard Deviation 0.73
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR A/H1N1/HAI seropositive/Dose1D5	3.35 log10 viral particles/mL Standard Deviation 0.64	—	3.73 log10 viral particles/mL Standard Deviation 0.62
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR A/H1N1/HAI seropositive/Dose1D7	3.10 log10 viral particles/mL Standard Deviation NA Standard deviation (SD) data not applicable as only one participant was evaluable for this reporting group.	—	—
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR A/H1N1/HAI seropositive/Dose2D2	3.38 log10 viral particles/mL Standard Deviation 0.78	2.86 log10 viral particles/mL Standard Deviation NA SD data not applicable as only one participant was evaluable for this reporting group.	3.36 log10 viral particles/mL Standard Deviation 0.56
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR A/H1N1/HAI seropositive/Dose2D4	—	—	3.65 log10 viral particles/mL Standard Deviation NA SD data not applicable as only one participant was evaluable for this reporting group.
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR A/H3N2/HAI seronegative/Dose1D2	4.20 log10 viral particles/mL Standard Deviation 0.99	4.15 log10 viral particles/mL Standard Deviation 0.93	3.52 log10 viral particles/mL Standard Deviation 0.77
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR A/H3N2/HAI seronegative/Dose1D3	5.20 log10 viral particles/mL Standard Deviation 1.12	5.39 log10 viral particles/mL Standard Deviation 1.19	4.34 log10 viral particles/mL Standard Deviation 0.86
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR A/H3N2/HAI seronegative/Dose1D4	4.86 log10 viral particles/mL Standard Deviation 0.99	4.51 log10 viral particles/mL Standard Deviation 1.14	4.51 log10 viral particles/mL Standard Deviation 1.05
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR A/H3N2/HAI seronegative/Dose1D5	4.04 log10 viral particles/mL Standard Deviation 1.09	4.16 log10 viral particles/mL Standard Deviation 1.20	3.67 log10 viral particles/mL Standard Deviation 1.06
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR A/H3N2/HAI seronegative/Dose1D7	4.10 log10 viral particles/mL Standard Deviation 0.97	4.12 log10 viral particles/mL Standard Deviation 0.88	3.58 log10 viral particles/mL Standard Deviation 1.26
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR A/H3N2/HAI seronegative/Dose2D2	3.67 log10 viral particles/mL Standard Deviation 1.03	3.33 log10 viral particles/mL Standard Deviation 0.67	3.01 log10 viral particles/mL Standard Deviation 0.49
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR A/H3N2/HAI seronegative/Dose2D4	—	3.41 log10 viral particles/mL Standard Deviation 0.26	3.68 log10 viral particles/mL Standard Deviation 0.70
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR A/H3N2/HAI seronegative/Dose2D6	—	2.72 log10 viral particles/mL Standard Deviation NA SD data not applicable as only one participant was evaluable for this reporting group.	3.05 log10 viral particles/mL Standard Deviation 0.61
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR A/H3N2/HAI seropositive/Dose1D2	3.80 log10 viral particles/mL Standard Deviation 1.07	3.98 log10 viral particles/mL Standard Deviation 1.02	3.19 log10 viral particles/mL Standard Deviation 0.67
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR A/H3N2/HAI seropositive/Dose1D3	4.79 log10 viral particles/mL Standard Deviation 1.29	5.06 log10 viral particles/mL Standard Deviation 1.20	3.54 log10 viral particles/mL Standard Deviation 0.98
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR A/H3N2/HAI seropositive/Dose1D4	4.34 log10 viral particles/mL Standard Deviation 1.03	4.45 log10 viral particles/mL Standard Deviation 1.14	4.00 log10 viral particles/mL Standard Deviation 1.24
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR A/H3N2/HAI seropositive/Dose1D5	3.99 log10 viral particles/mL Standard Deviation 1.05	4.01 log10 viral particles/mL Standard Deviation 0.98	3.98 log10 viral particles/mL Standard Deviation 0.72
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR A/H3N2/HAI seropositive/Dose1D7	3.92 log10 viral particles/mL Standard Deviation 1.06	4.10 log10 viral particles/mL Standard Deviation 1.36	3.30 log10 viral particles/mL Standard Deviation 0.55
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR A/H3N2/HAI seropositive/Dose2D6	3.82 log10 viral particles/mL Standard Deviation NA SD data not applicable as only one participant was evaluable for this reporting group.	2.32 log10 viral particles/mL Standard Deviation NA SD data not applicable as only one participant was evaluable for this reporting group.	3.17 log10 viral particles/mL Standard Deviation NA SD data not applicable as only one participant was evaluable for this reporting group.
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR B/Yamagata/HAI seronegative/Dose1D2	3.93 log10 viral particles/mL Standard Deviation 0.40	4.09 log10 viral particles/mL Standard Deviation 0.53	4.16 log10 viral particles/mL Standard Deviation 0.58
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR B/Yamagata/HAI seronegative/Dose1D3	4.10 log10 viral particles/mL Standard Deviation 0.60	4.60 log10 viral particles/mL Standard Deviation 0.77	4.72 log10 viral particles/mL Standard Deviation 0.92
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR B/Yamagata/HAI seronegative/Dose1D4	4.04 log10 viral particles/mL Standard Deviation 0.61	4.60 log10 viral particles/mL Standard Deviation 0.83	4.72 log10 viral particles/mL Standard Deviation 0.88
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR B/Yamagata/HAI seronegative/Dose1D5	4.56 log10 viral particles/mL Standard Deviation 0.53	4.42 log10 viral particles/mL Standard Deviation 0.72	4.59 log10 viral particles/mL Standard Deviation 0.80
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR B/Yamagata/HAI seronegative/Dose1D7	4.37 log10 viral particles/mL Standard Deviation 0.86	3.93 log10 viral particles/mL Standard Deviation 0.50	3.98 log10 viral particles/mL Standard Deviation 0.62
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR B/Yamagata/HAI seronegative/Dose2D2	3.92 log10 viral particles/mL Standard Deviation 0.31	4.10 log10 viral particles/mL Standard Deviation 0.55	3.80 log10 viral particles/mL Standard Deviation 0.35
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR B/Yamagata/HAI seronegative/Dose2D4	3.74 log10 viral particles/mL Standard Deviation 0.60	3.85 log10 viral particles/mL Standard Deviation 0.52	—
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR B/Yamagata/HAI seronegative/Dose2D6	3.83 log10 viral particles/mL Standard Deviation 0.35	—	—
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR B/Yamagata/HAI seropositive/Dose1D2	3.93 log10 viral particles/mL Standard Deviation 0.20	3.57 log10 viral particles/mL Standard Deviation 0.19	4.15 log10 viral particles/mL Standard Deviation 0.78
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR B/Yamagata/HAI seropositive/Dose1D3	3.93 log10 viral particles/mL Standard Deviation 0.58	3.92 log10 viral particles/mL Standard Deviation 0.51	4.67 log10 viral particles/mL Standard Deviation 0.79
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR B/Yamagata/HAI seropositive/Dose1D5	3.84 log10 viral particles/mL Standard Deviation NA SD data not applicable as only one participant was evaluable for this reporting group.	5.01 log10 viral particles/mL Standard Deviation NA SD data not applicable as only one participant was evaluable for this reporting group.	4.82 log10 viral particles/mL Standard Deviation 0.65
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR B/Yamagata/HAI seropositive/Dose1D7	5.46 log10 viral particles/mL Standard Deviation NA SD data not applicable as only one participant was evaluable for this reporting group.	—	3.91 log10 viral particles/mL Standard Deviation 0.63
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR B/Yamagata/HAI seropositive/Dose2D2	—	3.38 log10 viral particles/mL Standard Deviation NA SD data not applicable as only one participant was evaluable for this reporting group.	3.70 log10 viral particles/mL Standard Deviation 0.11
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR B/Yamagata/HAI seropositive/Dose2D6	3.92 log10 viral particles/mL Standard Deviation NA SD data not applicable as only one participant was evaluable for this reporting group.	—	—
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR B/Victoria/HAI seronegative/Dose1D2	—	3.41 log10 viral particles/mL Standard Deviation 0.58	3.49 log10 viral particles/mL Standard Deviation 0.72
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR B/Victoria/HAI seronegative/Dose1D5	—	3.98 log10 viral particles/mL Standard Deviation 1.05	4.09 log10 viral particles/mL Standard Deviation 1.02
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR B/Victoria/HAI seronegative/Dose1D7	—	3.57 log10 viral particles/mL Standard Deviation 0.79	4.14 log10 viral particles/mL Standard Deviation 0.84
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR B/Victoria/HAI seronegative/Dose2D2	—	3.43 log10 viral particles/mL Standard Deviation 1.01	2.94 log10 viral particles/mL Standard Deviation 0.36
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR B/Victoria/HAI seronegative/Dose2D4	—	3.48 log10 viral particles/mL Standard Deviation 0.88	2.67 log10 viral particles/mL Standard Deviation 0.29
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR B/Victoria/HAI seropositive/Dose1D2	—	2.73 log10 viral particles/mL Standard Deviation 0.01	3.10 log10 viral particles/mL Standard Deviation 0.53
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR B/Victoria/HAI seropositive/Dose1D3	—	3.09 log10 viral particles/mL Standard Deviation 0.42	3.96 log10 viral particles/mL Standard Deviation 1.08
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR B/Victoria/HAI seropositive/Dose1D4	—	2.73 log10 viral particles/mL Standard Deviation NA SD data not applicable as only one participant was evaluable for this reporting group.	4.40 log10 viral particles/mL Standard Deviation 0.98
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR B/Victoria/HAI seropositive/Dose1D5	—	—	4.26 log10 viral particles/mL Standard Deviation 0.90
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR B/Victoria/HAI seropositive/Dose1D7	—	—	4.00 log10 viral particles/mL Standard Deviation 0.96
Viral Titer by Day, Strain, Dose Number, and Baseline Serostatus as Measured by qRT-PCR B/Victoria/HAI seropositive/Dose2D2	—	—	3.41 log10 viral particles/mL Standard Deviation 0.51