Trial Outcomes & Findings for Evaluation of Human Immune Responses to Influenza Virus Vaccination in Healthy Volunteers (NCT NCT02385123)

NCT ID: NCT02385123

Last Updated: 2023-10-25

Results Overview

Hemagglutination inhibition titers were measured against reference influenza A/H1N1 and A/H3N2 strains, as well as influenza B Yamagata lineage influenza strains. Strains were matched to the composition of the vaccine received by each subject. For H1N1 and H3N2, hemagglutination was performed using receptor destroying enzyme (RDE)-treated plasma and turkey red blood cells following the World Health Organization (WHO) standard protocol. For influenza B, guinea pig red blood cells were used instead.

Recruitment status

TERMINATED

Study phase

PHASE4

Target enrollment

60 participants

Primary outcome timeframe

Day 28

Results posted on

2023-10-25

Participant Flow

The following methods were used to recruit participants: traditional flyers posted throughout campus, word of mouth referrals, and social media posts. In addition, listserves, and campus newsletters were also leveraged to expand our participant reach.

Participant milestones

Participant milestones
Measure
Seasonal Flu Vaccine/Healthy Adult Volunteers
This was an open label single arm study. For the purposes of this study, reportable adverse events were limited to any occurrence or worsening of an undesirable or unintended sign, symptom or disease that is specifically associated with a study procedure that is not part of the normal standard of care for the participant. There were minimal risks associated with venipuncture for obtaining research related labs. Foreseeable adverse events associated with venipuncture were: mild, temporary discomfort at the venipuncture site, bruising, and phlebitis. Very rarely, subjects may experience "vaso-vagal syndrome" during phlebotomy. Vaso-vagal reactions may include diaphoresis, nausea, syncope and rarely loss of consciousness. Anticipated adverse events related to administration of the inactivated influenza vaccine included: localized erythema, induration, swelling, itching and/or pain at the injection site, mild fever, myalgia, headache and malaise following vaccination. Since immunization with flu vaccine annually is offered as standard of care to healthy adults to prevent influenza infection, these anticipated reactions to the vaccine were not considered reportable adverse events. There were no illnesses requiring hospitalization that were deemed related to vaccination. Any adverse event listed by the vaccine manufacturer as a contraindication to further doses of the vaccine would have been considered an adverse event for the study.
Overall Study
STARTED
60
Overall Study
COMPLETED
45
Overall Study
NOT COMPLETED
15

Reasons for withdrawal

Reasons for withdrawal
Measure
Seasonal Flu Vaccine/Healthy Adult Volunteers
This was an open label single arm study. For the purposes of this study, reportable adverse events were limited to any occurrence or worsening of an undesirable or unintended sign, symptom or disease that is specifically associated with a study procedure that is not part of the normal standard of care for the participant. There were minimal risks associated with venipuncture for obtaining research related labs. Foreseeable adverse events associated with venipuncture were: mild, temporary discomfort at the venipuncture site, bruising, and phlebitis. Very rarely, subjects may experience "vaso-vagal syndrome" during phlebotomy. Vaso-vagal reactions may include diaphoresis, nausea, syncope and rarely loss of consciousness. Anticipated adverse events related to administration of the inactivated influenza vaccine included: localized erythema, induration, swelling, itching and/or pain at the injection site, mild fever, myalgia, headache and malaise following vaccination. Since immunization with flu vaccine annually is offered as standard of care to healthy adults to prevent influenza infection, these anticipated reactions to the vaccine were not considered reportable adverse events. There were no illnesses requiring hospitalization that were deemed related to vaccination. Any adverse event listed by the vaccine manufacturer as a contraindication to further doses of the vaccine would have been considered an adverse event for the study.
Overall Study
15 participants were unable to complete study. Research was halted due to Coronavirus Disease 2019.
15

Baseline Characteristics

Evaluation of Human Immune Responses to Influenza Virus Vaccination in Healthy Volunteers

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure
Seasonal Flu Vaccine/Healthy Adult Volunteers
n=60 Participants
This was an open label single arm study. For the purposes of this study, reportable adverse events were limited to any occurrence or worsening of an undesirable or unintended sign, symptom or disease that is specifically associated with a study procedure that is not part of the normal standard of care for the participant. There were minimal risks associated with venipuncture for obtaining research related labs. Foreseeable adverse events associated with venipuncture were: mild, temporary discomfort at the venipuncture site, bruising, and phlebitis. Very rarely, subjects may experience "vaso-vagal syndrome" during phlebotomy. Vaso-vagal reactions may include diaphoresis, nausea, syncope and rarely loss of consciousness. Anticipated adverse events related to administration of the inactivated influenza vaccine included: localized erythema, induration, swelling, itching and/or pain at the injection site, mild fever, myalgia, headache and malaise following vaccination. Since immunization with flu vaccine annually is offered as standard of care to healthy adults to prevent influenza infection, these anticipated reactions to the vaccine were not considered reportable adverse events. There were no illnesses requiring hospitalization that were deemed related to vaccination. Any adverse event listed by the vaccine manufacturer as a contraindication to further doses of the vaccine would have been considered an adverse event for the study.
Age, Categorical
<=18 years
0 Participants
n=39 Participants
Age, Categorical
Between 18 and 65 years
60 Participants
n=39 Participants
Age, Categorical
>=65 years
0 Participants
n=39 Participants
Age, Continuous
28.5 years
n=39 Participants
Sex: Female, Male
Female
33 Participants
n=39 Participants
Sex: Female, Male
Male
27 Participants
n=39 Participants
Ethnicity (NIH/OMB)
Hispanic or Latino
4 Participants
n=39 Participants
Ethnicity (NIH/OMB)
Not Hispanic or Latino
55 Participants
n=39 Participants
Ethnicity (NIH/OMB)
Unknown or Not Reported
1 Participants
n=39 Participants
Race (NIH/OMB)
American Indian or Alaska Native
0 Participants
n=39 Participants
Race (NIH/OMB)
Asian
22 Participants
n=39 Participants
Race (NIH/OMB)
Native Hawaiian or Other Pacific Islander
0 Participants
n=39 Participants
Race (NIH/OMB)
Black or African American
3 Participants
n=39 Participants
Race (NIH/OMB)
White
31 Participants
n=39 Participants
Race (NIH/OMB)
More than one race
1 Participants
n=39 Participants
Race (NIH/OMB)
Unknown or Not Reported
3 Participants
n=39 Participants
Region of Enrollment
United States
60 Participants
n=39 Participants

PRIMARY outcome

Timeframe: Day 28

Population: Of the 60 donors enrolled in this study, 45 donors were eligible to have their samples analyzed for this time-point outcome measure. Donors who did not provide a sample for this time-point due to missing this time-point visit were not included in the analysis.

Hemagglutination inhibition titers were measured against reference influenza A/H1N1 and A/H3N2 strains, as well as influenza B Yamagata lineage influenza strains. Strains were matched to the composition of the vaccine received by each subject. For H1N1 and H3N2, hemagglutination was performed using receptor destroying enzyme (RDE)-treated plasma and turkey red blood cells following the World Health Organization (WHO) standard protocol. For influenza B, guinea pig red blood cells were used instead.

Outcome measures

Outcome measures
Measure
Seasonal Flu Vaccine/Healthy Adult Volunteers
n=45 Participants
0.5 ml of seasonal inactivated influenza vaccine (IIV) was administered intramuscularly (IM) on Day 0 of each study season. Influenza Virus Vaccine Inactivated: A synthetic vaccine consisting of three inactivated influenza viruses: two different influenza type A strains and one influenza type B strain. Trivalent influenza vaccine is formulated annually, based on influenza strains projected to be prevalent in the upcoming flu season.
Percentage of Subjects Achieving Seroconversion (Pre-vaccination Hemagglutination Inhibition (HI) Titer <1:10 and a Post-vaccination HI Titer >1:40 or a Pre-vaccination HI Titer >1:10 and a Minimum Four-fold Rise in Post-vaccination HI Antibody Titer)
H1N1 seroconversion
28 Participants
Percentage of Subjects Achieving Seroconversion (Pre-vaccination Hemagglutination Inhibition (HI) Titer <1:10 and a Post-vaccination HI Titer >1:40 or a Pre-vaccination HI Titer >1:10 and a Minimum Four-fold Rise in Post-vaccination HI Antibody Titer)
H3N2 seroconversion
30 Participants
Percentage of Subjects Achieving Seroconversion (Pre-vaccination Hemagglutination Inhibition (HI) Titer <1:10 and a Post-vaccination HI Titer >1:40 or a Pre-vaccination HI Titer >1:10 and a Minimum Four-fold Rise in Post-vaccination HI Antibody Titer)
Influenza B Yamagata lineage seroconversion
32 Participants

PRIMARY outcome

Timeframe: Day 0

Population: Of the 60 donors enrolled in this study, 45 donors were eligible to have their samples analyzed for this time-point outcome measure. Donors who did not provide a sample for this time-point due to missing this time-point visit were not included in the analysis.

Hemagglutination inhibition titers were measured against reference influenza A/H1N1 and A/H3N2 strains, as well as influenza B Yamagata lineage influenza strains. Strains were matched to the composition of the vaccine received by each subject. For H1N1 and H3N2, hemagglutination was performed using RDE-treated plasma and turkey red blood cells following the WHO standard protocol. For influenza B, guinea pig red blood cells were used instead.

Outcome measures

Outcome measures
Measure
Seasonal Flu Vaccine/Healthy Adult Volunteers
n=45 Participants
0.5 ml of seasonal inactivated influenza vaccine (IIV) was administered intramuscularly (IM) on Day 0 of each study season. Influenza Virus Vaccine Inactivated: A synthetic vaccine consisting of three inactivated influenza viruses: two different influenza type A strains and one influenza type B strain. Trivalent influenza vaccine is formulated annually, based on influenza strains projected to be prevalent in the upcoming flu season.
Percentage of Subjects With Pre-vaccination Titer <1:40
A/H1N1 HAI titer <1:40 on day 0
24 Participants
Percentage of Subjects With Pre-vaccination Titer <1:40
A/H3N2 HAI titer <1:40 on day 0
25 Participants
Percentage of Subjects With Pre-vaccination Titer <1:40
B Yamagata lineage HAI titer <1:40 on day 0
13 Participants

SECONDARY outcome

Timeframe: Day 0

Population: Of the 60 donors for this study, 25 donors received the 2017-18 or 2018-19 vaccine. 1 donor did not have plasma samples available for all timepoints and was excluded from ELISA analysis.

ELISAs were performed using serial dilutions of plasma incubated on Maxisorp ELISA plates coated with 50 nanograms per well of H1N1 hemagglutinin protein from strain A/Michigan/45/2015. Plasma samples were drawn from donors who received the 2017-18 or 2018-19 influenza vaccine. Bound serum IgG was detected using 1:1000 diluted goat anti-human IgG-horseradish peroxidase (HRP) from Jackson Immunoresearch and plates were developed using o-phenylenediamine (OPD) substrate and developed for 7 minutes. The ELISA endpoint titer was defined as the reciprocal dilution of plasma that produced a background-subtracted optical density at 490 (OD490) value of 0.3, corresponding to 10% of maximum binding. Endpoint titers were determined by interpolation from the serial dilution curve results using Graphpad Prism software.

Outcome measures

Outcome measures
Measure
Seasonal Flu Vaccine/Healthy Adult Volunteers
n=24 Participants
0.5 ml of seasonal inactivated influenza vaccine (IIV) was administered intramuscularly (IM) on Day 0 of each study season. Influenza Virus Vaccine Inactivated: A synthetic vaccine consisting of three inactivated influenza viruses: two different influenza type A strains and one influenza type B strain. Trivalent influenza vaccine is formulated annually, based on influenza strains projected to be prevalent in the upcoming flu season.
Endpoint Immunoglobulin G (IgG) Titers for Serum Antibody Responses Directed Against the Full Length A/H1N1 Hemagglutinin (HA) Protein
11851 H1 HA ELISA endpoint reciprocal dilution
Interval 4170.0 to 39548.0

SECONDARY outcome

Timeframe: Day 180

Population: Of the 60 donors for this study, 25 donors received the 2017-18 or 2018-19 vaccine. 1 donor did not have plasma samples available for all timepoints and was excluded from ELISA analysis.

ELISAs were performed using serial dilutions of plasma incubated on Maxisorp ELISA plates coated with 50 nanograms per well of H1N1 hemagglutinin protein from strain A/Michigan/45/2015. Plasma samples were drawn from donors who received the 2017-18 or 2018-19 influenza vaccine. Bound serum IgG was detected using 1:1000 diluted goat anti-human IgG-HRP from Jackson Immunoresearch and plates were developed using OPD substrate and developed for 7 minutes. The ELISA endpoint titer was defined as the reciprocal dilution of plasma that produced a background-subtracted OD490 value of 0.3, corresponding to 10% of maximum binding. Endpoint titers were determined by interpolation from the serial dilution curve results using Graphpad Prism software.

Outcome measures

Outcome measures
Measure
Seasonal Flu Vaccine/Healthy Adult Volunteers
n=24 Participants
0.5 ml of seasonal inactivated influenza vaccine (IIV) was administered intramuscularly (IM) on Day 0 of each study season. Influenza Virus Vaccine Inactivated: A synthetic vaccine consisting of three inactivated influenza viruses: two different influenza type A strains and one influenza type B strain. Trivalent influenza vaccine is formulated annually, based on influenza strains projected to be prevalent in the upcoming flu season.
Endpoint IgG Titers for Serum Antibody Responses Directed Against the Full Length A/H1N1 Hemagglutinin (HA) Protein
48445 H1 HA ELISA endpoint reciprocal dilution
Interval 30675.0 to 78013.0

SECONDARY outcome

Timeframe: Day 28

Population: Of the 60 donors for this study, 25 donors received the 2017-18 or 2018-19 vaccine. 1 donor did not have plasma samples available for all timepoints and was excluded from ELISA analysis.

ELISAs were performed using serial dilutions of plasma incubated on Maxisorp ELISA plates coated with 50 nanograms per well of H1N1 hemagglutinin protein from strain A/Michigan/45/2015. Plasma samples were drawn from donors who received the 2017-18 or 2018-19 influenza vaccine. Bound serum IgG was detected using 1:1000 diluted goat anti-human IgG-HRP from Jackson Immunoresearch and plates were developed using OPD substrate and developed for 7 minutes. The ELISA endpoint titer was defined as the reciprocal dilution of plasma that produced a background-subtracted OD490 value of 0.3, corresponding to 10% of maximum binding. Endpoint titers were determined by interpolation from the serial dilution curve results using Graphpad Prism software.

Outcome measures

Outcome measures
Measure
Seasonal Flu Vaccine/Healthy Adult Volunteers
n=24 Participants
0.5 ml of seasonal inactivated influenza vaccine (IIV) was administered intramuscularly (IM) on Day 0 of each study season. Influenza Virus Vaccine Inactivated: A synthetic vaccine consisting of three inactivated influenza viruses: two different influenza type A strains and one influenza type B strain. Trivalent influenza vaccine is formulated annually, based on influenza strains projected to be prevalent in the upcoming flu season.
Endpoint IgG Titers for Serum Antibody Responses Directed Against the Full Length A/H1N1 Hemagglutinin (HA) Protein
121284 H1 HA ELISA endpoint reciprocal dilution
Interval 66218.0 to 190689.0

SECONDARY outcome

Timeframe: Day 0

Population: Of the 60 donors for this study, 25 donors received the 2017-18 or 2018-19 vaccine. 1 donor did not have plasma samples available for all timepoints and was excluded from ELISA analysis.

ELISAs were performed using serial dilutions of plasma incubated on Maxisorp ELISA plates coated with 50 nanograms per well of a chimeric HA protein containing the head domain from an H6 influenza virus and the stem domain from A/California/07/2009. Plasma samples were drawn from donors who received the 2017-18 or 2018-19 influenza vaccine. Bound serum IgG was detected using 1:1000 diluted goat anti-human IgG-HRP from Jackson Immunoresearch and plates were developed using OPD substrate and developed for 7 minutes. The ELISA endpoint titer was defined as the reciprocal dilution of plasma that produced a background-subtracted OD490 value of 0.3, corresponding to 10% of maximum binding. Endpoint titers were determined by interpolation from the serial dilution curve results using Graphpad Prism software.

Outcome measures

Outcome measures
Measure
Seasonal Flu Vaccine/Healthy Adult Volunteers
n=24 Participants
0.5 ml of seasonal inactivated influenza vaccine (IIV) was administered intramuscularly (IM) on Day 0 of each study season. Influenza Virus Vaccine Inactivated: A synthetic vaccine consisting of three inactivated influenza viruses: two different influenza type A strains and one influenza type B strain. Trivalent influenza vaccine is formulated annually, based on influenza strains projected to be prevalent in the upcoming flu season.
Endpoint IgG Titers for Serum Antibody Responses Directed Against the H1N1 Hemagglutinin (HA) Stem Region
11140 stem ELISA endpoint reciprocal dilution
Interval 7032.0 to 22360.0

SECONDARY outcome

Timeframe: Day 180

Population: Of the 60 donors for this study, 25 donors received the 2017-18 or 2018-19 vaccine. 1 donor did not have plasma samples available for all timepoints and was excluded from ELISA analysis.

ELISAs were performed using serial dilutions of plasma incubated on Maxisorp ELISA plates coated with 50 nanograms per well of a chimeric HA protein containing the head domain from an H6 influenza virus and the stem domain from A/California/07/2009. Plasma samples were drawn from donors who received the 2017-18 or 2018-19 influenza vaccine. Bound serum IgG was detected using 1:1000 diluted goat anti-human IgG-HRP from Jackson Immunoresearch and plates were developed using OPD substrate and developed for 7 minutes. The ELISA endpoint titer was defined as the reciprocal dilution of plasma that produced a background-subtracted OD490 value of 0.3, corresponding to 10% of maximum binding. Endpoint titers were determined by interpolation from the serial dilution curve results using Graphpad Prism software.

Outcome measures

Outcome measures
Measure
Seasonal Flu Vaccine/Healthy Adult Volunteers
n=24 Participants
0.5 ml of seasonal inactivated influenza vaccine (IIV) was administered intramuscularly (IM) on Day 0 of each study season. Influenza Virus Vaccine Inactivated: A synthetic vaccine consisting of three inactivated influenza viruses: two different influenza type A strains and one influenza type B strain. Trivalent influenza vaccine is formulated annually, based on influenza strains projected to be prevalent in the upcoming flu season.
Endpoint IgG Titers for Serum Antibody Responses Directed Against the H1N1 Hemagglutinin (HA) Stem Region
16694 stem ELISA endpoint reciprocal dilution
Interval 7818.0 to 32048.0

SECONDARY outcome

Timeframe: Day 28

Population: Of the 60 donors for this study, 25 donors received the 2017-18 or 2018-19 vaccine. 1 donor did not have plasma samples available for all timepoints and was excluded from ELISA analysis.

ELISAs were performed using serial dilutions of plasma incubated on Maxisorp ELISA plates coated with 50 nanograms per well of a chimeric HA protein containing the head domain from an H6 influenza virus and the stem domain from A/California/07/2009. Plasma samples were drawn from donors who received the 2017-18 or 2018-19 influenza vaccine. Bound serum IgG was detected using 1:1000 diluted goat anti-human IgG-HRP from Jackson Immunoresearch and plates were developed using OPD substrate and developed for 7 minutes. The ELISA endpoint titer was defined as the reciprocal dilution of plasma that produced a background-subtracted OD490 value of 0.3, corresponding to 10% of maximum binding. Endpoint titers were determined by interpolation from the serial dilution curve results using Graphpad Prism software.

Outcome measures

Outcome measures
Measure
Seasonal Flu Vaccine/Healthy Adult Volunteers
n=24 Participants
0.5 ml of seasonal inactivated influenza vaccine (IIV) was administered intramuscularly (IM) on Day 0 of each study season. Influenza Virus Vaccine Inactivated: A synthetic vaccine consisting of three inactivated influenza viruses: two different influenza type A strains and one influenza type B strain. Trivalent influenza vaccine is formulated annually, based on influenza strains projected to be prevalent in the upcoming flu season.
Endpoint IgG Titers for Serum Antibody Responses Directed Against the H1N1 Hemagglutinin (HA) Stem Region.
29905 stem ELISA endpoint reciprocal dilution
Interval 18411.0 to 42782.0

SECONDARY outcome

Timeframe: Day 7

Population: Influenza-specific monoclonal antibodies (mAbs) were cloned from Day 7 plasmablasts from a single donor.

Monoclonal antibodies were cloned from sorted H1 hemagglutinin-binding cells expressing high levels of the CD38 protein (CD38hi) plasmablasts isolated from a single donor on day 7 post vaccination.

Outcome measures

Outcome measures
Measure
Seasonal Flu Vaccine/Healthy Adult Volunteers
n=1 Participants
0.5 ml of seasonal inactivated influenza vaccine (IIV) was administered intramuscularly (IM) on Day 0 of each study season. Influenza Virus Vaccine Inactivated: A synthetic vaccine consisting of three inactivated influenza viruses: two different influenza type A strains and one influenza type B strain. Trivalent influenza vaccine is formulated annually, based on influenza strains projected to be prevalent in the upcoming flu season.
Expression of Human Influenza-specific Monoclonal Antibodies From Plasmablasts
6 number of mAbs cloned

SECONDARY outcome

Timeframe: Day 0

Population: Of the 60 donors enrolled in this study, 25 donors received the 2017-18 or 2018-19 influenza vaccine. Two did not have peripheral blood mononuclear cell (PBMC) samples available at all timepoints and were excluded from analysis.

Peripheral blood mononuclear cells from volunteers who received the 2017-18 or 2018-19 influenza vaccine were stimulated with R-848/interleukin (IL)-2 to induce polyclonal plasmablast differentiation. Total H1-specific memory B cells were detected using hemagglutinin protein from A/Michigan/45/2015 as an ELISPOT capture antigen and IgG detection. Frequencies were expressed as a percentage of the spots observed using total IgG capture antibody. Head specific memory B cell frequencies were calculated by subtracting the percentage of stem-specific IgG memory B cells from the percentage of total H1-specific cells.

Outcome measures

Outcome measures
Measure
Seasonal Flu Vaccine/Healthy Adult Volunteers
n=23 Participants
0.5 ml of seasonal inactivated influenza vaccine (IIV) was administered intramuscularly (IM) on Day 0 of each study season. Influenza Virus Vaccine Inactivated: A synthetic vaccine consisting of three inactivated influenza viruses: two different influenza type A strains and one influenza type B strain. Trivalent influenza vaccine is formulated annually, based on influenza strains projected to be prevalent in the upcoming flu season.
Frequency of Hemagglutinin (HA) Head-specific IgG Secreting Memory B Cells Per Total IgG Secreting Cells
0.039 % of IgG memory B cells
Interval 0.027 to 0.063

SECONDARY outcome

Timeframe: Day 180

Population: Of the 60 donors enrolled in this study, 25 donors received the 2017-18 or 2018-19 influenza vaccine. 2 did not have PBMC samples available at all timepoints and were excluded from analysis.

Peripheral blood mononuclear cells from volunteers who received the 2017-18 or 2018-19 influenza vaccine were stimulated with R-848/IL-2 to induce polyclonal plasmablast differentiation. Total H1-specific memory B cells were detected using hemagglutinin protein from A/Michigan/45/2015 as an ELISPOT capture antigen and IgG detection. Frequencies were expressed as a percentage of the spots observed using total IgG capture antibody. Head specific memory B cell frequencies were calculated by subtracting the percentage of stem-specific IgG memory B cells from the percentage of total H1-specific cells.

Outcome measures

Outcome measures
Measure
Seasonal Flu Vaccine/Healthy Adult Volunteers
n=23 Participants
0.5 ml of seasonal inactivated influenza vaccine (IIV) was administered intramuscularly (IM) on Day 0 of each study season. Influenza Virus Vaccine Inactivated: A synthetic vaccine consisting of three inactivated influenza viruses: two different influenza type A strains and one influenza type B strain. Trivalent influenza vaccine is formulated annually, based on influenza strains projected to be prevalent in the upcoming flu season.
Frequency of Hemagglutinin (HA) Head-specific IgG Secreting Memory B Cells Per Total IgG Secreting Cells
0.17 % of IgG memory B cells
Interval 0.084 to 0.32

SECONDARY outcome

Timeframe: Day 28

Population: Of the 60 donors enrolled in this study, 25 donors received the 2017-18 or 2018-19 influenza vaccine. 2 did not have PBMC samples available at all timepoints and were excluded from analysis.

Peripheral blood mononuclear cells from volunteers who received the 2017-18 or 2018-19 influenza vaccine were stimulated with R-848/IL-2 to induce polyclonal plasmablast differentiation. Total H1-specific memory B cells were detected using hemagglutinin protein from A/Michigan/45/2015 as an ELISPOT capture antigen and IgG detection. Frequencies were expressed as a percentage of the spots observed using total IgG capture antibody. Head specific memory B cell frequencies were calculated by subtracting the percentage of stem-specific IgG memory B cells from the percentage of total H1-specific cells.

Outcome measures

Outcome measures
Measure
Seasonal Flu Vaccine/Healthy Adult Volunteers
n=23 Participants
0.5 ml of seasonal inactivated influenza vaccine (IIV) was administered intramuscularly (IM) on Day 0 of each study season. Influenza Virus Vaccine Inactivated: A synthetic vaccine consisting of three inactivated influenza viruses: two different influenza type A strains and one influenza type B strain. Trivalent influenza vaccine is formulated annually, based on influenza strains projected to be prevalent in the upcoming flu season.
Frequency of Hemagglutinin (HA) Head-specific IgG Secreting Memory B Cells Per Total IgG Secreting Cells
0.63 % of IgG memory B cells
Interval 0.27 to 1.5

SECONDARY outcome

Timeframe: Day 0

Population: Of the 60 donors enrolled in this study, 25 donors received the 2017-18 or 2018-19 influenza vaccine. 2 did not have PBMC samples available at all timepoints and were excluded from analysis.

Peripheral blood mononuclear cells from volunteers who received the 2017-18 or 2018-19 influenza vaccine were stimulated with R-848/IL-2 to induce polyclonal plasmablast differentiation. Stem-specific memory B cells were detected using a chimeric hemagglutinin containing an H6 influenza head domain and the stem domain from A/California/07/2009 as an ELISPOT capture antigen. Frequencies were expressed as a percentage of the spots observed using total IgG capture antibody.

Outcome measures

Outcome measures
Measure
Seasonal Flu Vaccine/Healthy Adult Volunteers
n=23 Participants
0.5 ml of seasonal inactivated influenza vaccine (IIV) was administered intramuscularly (IM) on Day 0 of each study season. Influenza Virus Vaccine Inactivated: A synthetic vaccine consisting of three inactivated influenza viruses: two different influenza type A strains and one influenza type B strain. Trivalent influenza vaccine is formulated annually, based on influenza strains projected to be prevalent in the upcoming flu season.
Frequency of Hemagglutinin (HA) Stem-specific IgG Secreting Memory B Cells Per Total IgG Secreting Cells
0.023 % of IgG memory B cells
Interval 0.0094 to 0.041

SECONDARY outcome

Timeframe: Day 180

Population: Of the 60 donors enrolled in this study, 25 donors received the 2017-18 or 2018-19 influenza vaccine. 2 did not have PBMC samples available at all timepoints and were excluded from analysis.

Peripheral blood mononuclear cells from volunteers who received the 2017-18 or 2018-19 influenza vaccine were stimulated with R-848/IL-2 to induce polyclonal plasmablast differentiation. Stem-specific memory B cells were detected using a chimeric hemagglutinin containing an H6 influenza head domain and the stem domain from A/California/07/2009 as an ELISPOT capture antigen. Frequencies were expressed as a percentage of the spots observed using total IgG capture antibody.

Outcome measures

Outcome measures
Measure
Seasonal Flu Vaccine/Healthy Adult Volunteers
n=23 Participants
0.5 ml of seasonal inactivated influenza vaccine (IIV) was administered intramuscularly (IM) on Day 0 of each study season. Influenza Virus Vaccine Inactivated: A synthetic vaccine consisting of three inactivated influenza viruses: two different influenza type A strains and one influenza type B strain. Trivalent influenza vaccine is formulated annually, based on influenza strains projected to be prevalent in the upcoming flu season.
Frequency of Hemagglutinin (HA) Stem-specific IgG Secreting Memory B Cells Per Total IgG Secreting Cells
0.088 % of IgG memory B cells
Interval 0.056 to 0.13

SECONDARY outcome

Timeframe: Day 28

Population: Of the 60 donors enrolled in this study, 25 donors received the 2017-18 or 2018-19 influenza vaccine. 2 did not have PBMC samples available at all timepoints and were excluded from analysis.

Peripheral blood mononuclear cells from volunteers who received the 2017-18 or 2018-19 influenza vaccine were stimulated with R-848/IL-2 to induce polyclonal plasmablast differentiation. Stem-specific memory B cells were detected using a chimeric hemagglutinin containing an H6 influenza head domain and the stem domain from A/California/07/2009 as an ELISPOT capture antigen. Frequencies were expressed as a percentage of the spots observed using total IgG capture antibody.

Outcome measures

Outcome measures
Measure
Seasonal Flu Vaccine/Healthy Adult Volunteers
n=23 Participants
0.5 ml of seasonal inactivated influenza vaccine (IIV) was administered intramuscularly (IM) on Day 0 of each study season. Influenza Virus Vaccine Inactivated: A synthetic vaccine consisting of three inactivated influenza viruses: two different influenza type A strains and one influenza type B strain. Trivalent influenza vaccine is formulated annually, based on influenza strains projected to be prevalent in the upcoming flu season.
Frequency of Hemagglutinin (HA) Stem-specific IgG Secreting Memory B Cells Per Total IgG Secreting Cells
0.17 % of IgG memory B cells
Interval 0.091 to 0.29

SECONDARY outcome

Timeframe: Day 7

Population: All six antibodies were isolated from a single donor.

Madin-Darby canine kidney (MDCK) cells in 96-well plates were infected in duplicate for 5 hours with H1N1 influenza virus (strain A/Michigan/45/2015) that had been pre-incubated for 15 minutes at 37 degrees with influenza monoclonal antibodies. Pre-incubations were performed using serial 2-fold dilutions of each monoclonal antibody, beginning at a concentration of 30 micrograms per milliliter. Virus was used at a dose sufficient to yield 5% infection in the absence of antibody. Infection was assessed after 5 hours in methanol-permeabilized cells by staining with an influenza nucleoprotein-specific mouse antibody (HB65), then phycoerythrin (PE)-conjugated anti-mouse IgG, followed by identification of PE-positive cells by flow cytometry. The 50% neutralizing titer reported is equivalent to the lowest monoclonal antibody concentration that resulted in a greater than or equal to 2-fold reduction in viral infection relative to the no-antibody control.

Outcome measures

Outcome measures
Measure
Seasonal Flu Vaccine/Healthy Adult Volunteers
n=6 monoclonal antibodies
0.5 ml of seasonal inactivated influenza vaccine (IIV) was administered intramuscularly (IM) on Day 0 of each study season. Influenza Virus Vaccine Inactivated: A synthetic vaccine consisting of three inactivated influenza viruses: two different influenza type A strains and one influenza type B strain. Trivalent influenza vaccine is formulated annually, based on influenza strains projected to be prevalent in the upcoming flu season.
Function of Human Influenza-specific Monoclonal Antibodies Assessed by Virus Neutralization Assay
0.94 50% neutralizing conc. (micrograms/ml)
Interval 0.58 to 1.9

SECONDARY outcome

Timeframe: Day 7

Population: All six mAbs were isolated from a single donor.

Influenza-specific mAbs were assessed for HA binding by ELISA using recombinant HA protein from H1N1 strain A/California/07/2009. 50 ng of HA were coated per well in Maxisorp ELISA plates and serial dilutions of mAb were added. The concentration of each mAb that gave 50% maximal binding (EC50) was determined.

Outcome measures

Outcome measures
Measure
Seasonal Flu Vaccine/Healthy Adult Volunteers
n=6 monoclonal antibodies
0.5 ml of seasonal inactivated influenza vaccine (IIV) was administered intramuscularly (IM) on Day 0 of each study season. Influenza Virus Vaccine Inactivated: A synthetic vaccine consisting of three inactivated influenza viruses: two different influenza type A strains and one influenza type B strain. Trivalent influenza vaccine is formulated annually, based on influenza strains projected to be prevalent in the upcoming flu season.
Function of Human Influenza-specific Monoclonal Antibodies Assessed by Enzyme-Linked Immunosorbent Assay (ELISA)
0.13 ELISA EC50 titer in micrograms per ml
Interval 0.087 to 0.274

SECONDARY outcome

Timeframe: Day 7

Population: All six mAbs were isolated from a single donor.

The HAI titer for each antibody was determined using the World Health Organization (WHO) standard protocol using H1N1 strain A/Michigan/45/2015.

Outcome measures

Outcome measures
Measure
Seasonal Flu Vaccine/Healthy Adult Volunteers
n=6 monoclonal antibodies
0.5 ml of seasonal inactivated influenza vaccine (IIV) was administered intramuscularly (IM) on Day 0 of each study season. Influenza Virus Vaccine Inactivated: A synthetic vaccine consisting of three inactivated influenza viruses: two different influenza type A strains and one influenza type B strain. Trivalent influenza vaccine is formulated annually, based on influenza strains projected to be prevalent in the upcoming flu season.
Function of Human Influenza-specific Monoclonal Antibodies Assessed by Hemagglutination Inhibition (HAI) Assay
7.5 HAI titer (micrograms per millliliter)
Interval 5.0 to 10.0

SECONDARY outcome

Timeframe: Day 0

Population: Samples were taken from donors who enrolled in the 2016-17 through 2019-20 seasons.

ELISA titers were measured against the matched seasonal quadrivalent inactivated influenza vaccine received by each subject using a secondary antibody specific for human IgG1. The endpoint ELISA titer was defined as the reciprocal dilution of plasma that gave an optical density (OD) reading of 0.2, which corresponded to \~3 standard deviations above the background OD for ELISA wells incubated without plasma.

Outcome measures

Outcome measures
Measure
Seasonal Flu Vaccine/Healthy Adult Volunteers
n=33 Participants
0.5 ml of seasonal inactivated influenza vaccine (IIV) was administered intramuscularly (IM) on Day 0 of each study season. Influenza Virus Vaccine Inactivated: A synthetic vaccine consisting of three inactivated influenza viruses: two different influenza type A strains and one influenza type B strain. Trivalent influenza vaccine is formulated annually, based on influenza strains projected to be prevalent in the upcoming flu season.
Quadrivalent Influenza Vaccine Immunoglobulin Gamma-1 (IgG1) ELISA Endpoint Titer
1877 Reciprocal endpoint plasma dilution
Interval 1435.0 to 2489.0

SECONDARY outcome

Timeframe: Day 180

Population: Samples were taken from donors who enrolled in the 2016-17 through 2018-19 seasons. Due to the COronaVIrus Disease of 2019 (COVID-19) pandemic, no samples could be drawn for this day 180 timepoint in the 2019-2020 season.

ELISA titers were measured against the matched seasonal quadrivalent inactivated influenza vaccine received by each subject using a secondary antibody specific for human IgG1. The endpoint ELISA titer was defined as the reciprocal dilution of plasma that gave an optical density (OD) reading of 0.2, which corresponded to \~3 standard deviations above the background OD for ELISA wells incubated without plasma.

Outcome measures

Outcome measures
Measure
Seasonal Flu Vaccine/Healthy Adult Volunteers
n=17 Participants
0.5 ml of seasonal inactivated influenza vaccine (IIV) was administered intramuscularly (IM) on Day 0 of each study season. Influenza Virus Vaccine Inactivated: A synthetic vaccine consisting of three inactivated influenza viruses: two different influenza type A strains and one influenza type B strain. Trivalent influenza vaccine is formulated annually, based on influenza strains projected to be prevalent in the upcoming flu season.
Quadrivalent Influenza Vaccine IgG1 ELISA Endpoint Titer
3026 Reciprocal endpoint plasma dilution
Interval 2453.0 to 3722.0

SECONDARY outcome

Timeframe: Day 28

Population: Samples were taken from donors who enrolled in the 2016-17 through 2019-20 seasons.

ELISA titers were measured against the matched seasonal quadrivalent inactivated influenza vaccine received by each subject using a secondary antibody specific for human IgG1. The endpoint ELISA titer was defined as the reciprocal dilution of plasma that gave an optical density (OD) reading of 0.2, which corresponded to \~3 standard deviations above the background OD for ELISA wells incubated without plasma.

Outcome measures

Outcome measures
Measure
Seasonal Flu Vaccine/Healthy Adult Volunteers
n=32 Participants
0.5 ml of seasonal inactivated influenza vaccine (IIV) was administered intramuscularly (IM) on Day 0 of each study season. Influenza Virus Vaccine Inactivated: A synthetic vaccine consisting of three inactivated influenza viruses: two different influenza type A strains and one influenza type B strain. Trivalent influenza vaccine is formulated annually, based on influenza strains projected to be prevalent in the upcoming flu season.
Quadrivalent Influenza Vaccine IgG1 ELISA Endpoint Titer
3744 reciprocal endpoint titer
Interval 3018.0 to 4356.0

SECONDARY outcome

Timeframe: Day 7

Population: Plasmablast responses to H1 head and stem were analyzed using day 7 PBMC from a subset of 14 donors who had a strong vaccine response to H1 hemagglutinin as determined by ELISA.

Plasmablasts (PB) were enumerated directly from frozen PBMC without stimulation. Total H1-specific cells were detected using hemagglutinin protein from A/Michigan/45/2015 as an ELISPOT capture antigen and IgG detection. Frequencies were expressed as the number of spots observed per million peripheral blood mononuclear cells. Head specific PB frequencies were calculated by subtracting the number of stem-specific PB per million peripheral blood mononuclear cells from the number of total H1-specific PB per million cells.

Outcome measures

Outcome measures
Measure
Seasonal Flu Vaccine/Healthy Adult Volunteers
n=14 Participants
0.5 ml of seasonal inactivated influenza vaccine (IIV) was administered intramuscularly (IM) on Day 0 of each study season. Influenza Virus Vaccine Inactivated: A synthetic vaccine consisting of three inactivated influenza viruses: two different influenza type A strains and one influenza type B strain. Trivalent influenza vaccine is formulated annually, based on influenza strains projected to be prevalent in the upcoming flu season.
Plasmablast Responses Against Hemagglutinin (HA) Head Antigens Assessed by Direct ex Vivo Enzyme-linked Immunospot (ELISPOT)
1096 Head-specific IgG PB per million PBMC
Interval 635.0 to 2060.0

SECONDARY outcome

Timeframe: Day 7

Population: Plasmablast responses to H1 head and stem were analyzed using day 7 PBMC from a subset of 14 donors who had a strong vaccine response to H1 hemagglutinin as determined by ELISA.

Plasmablasts (PB) were enumerated directly from frozen PBMC without stimulation. Stem-specific cells were detected using a chimeric hemagglutinin containing an H6 influenza head domain and the stem domain from A/California/07/2009 as an ELISPOT capture antigen and IgG detection. Frequencies were expressed as the number of spots observed per million peripheral blood mononuclear cells.

Outcome measures

Outcome measures
Measure
Seasonal Flu Vaccine/Healthy Adult Volunteers
n=14 Participants
0.5 ml of seasonal inactivated influenza vaccine (IIV) was administered intramuscularly (IM) on Day 0 of each study season. Influenza Virus Vaccine Inactivated: A synthetic vaccine consisting of three inactivated influenza viruses: two different influenza type A strains and one influenza type B strain. Trivalent influenza vaccine is formulated annually, based on influenza strains projected to be prevalent in the upcoming flu season.
Plasmablast Responses Against Hemagglutinin (HA) Stem Antigens Assessed by Direct ex Vivo Enzyme-linked Immunospot (ELISPOT)
47.6 Stem-specific IgG PB per million PBMC
Interval 15.5 to 98.5

Adverse Events

Seasonal Flu Vaccine/Healthy Adult Volunteers

Serious events: 0 serious events
Other events: 9 other events
Deaths: 0 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Other adverse events
Measure
Seasonal Flu Vaccine/Healthy Adult Volunteers
n=60 participants at risk
This was an open label single arm study. For the purposes of this study, reportable adverse events were limited to any occurrence or worsening of an undesirable or unintended sign, symptom or disease that is specifically associated with a study procedure that is not part of the normal standard of care for the participant. There were minimal risks associated with venipuncture for obtaining research related labs. Foreseeable adverse events associated with venipuncture were: mild, temporary discomfort at the venipuncture site, bruising, and phlebitis. Very rarely, subjects may experience "vaso-vagal syndrome" during phlebotomy. Vaso-vagal reactions may include diaphoresis, nausea, syncope and rarely loss of consciousness. Anticipated adverse events related to administration of the inactivated influenza vaccine included: localized erythema, induration, swelling, itching and/or pain at the injection site, mild fever, myalgia, headache and malaise following vaccination. Since immunization with flu vaccine annually is offered as standard of care to healthy adults to prevent influenza infection, these anticipated reactions to the vaccine were not considered reportable adverse events. There were no illnesses requiring hospitalization that were deemed related to vaccination. Any adverse event listed by the vaccine manufacturer as a contraindication to further doses of the vaccine would have been considered an adverse event for the study.
Infections and infestations
Sore throat (pharyngitis)
3.3%
2/60 • Number of events 2 • 6 months Adverse event data were collected from Day 0 (enrollment) to Day 180 (the end of follow-up). Adverse event data were collected at each of the follow-up visits (Day 7, Day 14, Day 28, Day 90, and Day 180).
At each of the follow-up visits (Day 7, Day 14, Day 28, Day 90, and Day 180), participants were asked about any adverse events that they might have experienced since their last visit. Clinical health assessments were conducted at every study visit, and included inquiry regarding any illness, any change in medication, and any overall health changes since the last study visit. Adverse event data was collected from enrollment until the end of follow-up at Day 180.
Ear and labyrinth disorders
Ear pain
1.7%
1/60 • Number of events 1 • 6 months Adverse event data were collected from Day 0 (enrollment) to Day 180 (the end of follow-up). Adverse event data were collected at each of the follow-up visits (Day 7, Day 14, Day 28, Day 90, and Day 180).
At each of the follow-up visits (Day 7, Day 14, Day 28, Day 90, and Day 180), participants were asked about any adverse events that they might have experienced since their last visit. Clinical health assessments were conducted at every study visit, and included inquiry regarding any illness, any change in medication, and any overall health changes since the last study visit. Adverse event data was collected from enrollment until the end of follow-up at Day 180.
Infections and infestations
Urinary tract infection
1.7%
1/60 • Number of events 1 • 6 months Adverse event data were collected from Day 0 (enrollment) to Day 180 (the end of follow-up). Adverse event data were collected at each of the follow-up visits (Day 7, Day 14, Day 28, Day 90, and Day 180).
At each of the follow-up visits (Day 7, Day 14, Day 28, Day 90, and Day 180), participants were asked about any adverse events that they might have experienced since their last visit. Clinical health assessments were conducted at every study visit, and included inquiry regarding any illness, any change in medication, and any overall health changes since the last study visit. Adverse event data was collected from enrollment until the end of follow-up at Day 180.
General disorders
Influenza
5.0%
3/60 • Number of events 3 • 6 months Adverse event data were collected from Day 0 (enrollment) to Day 180 (the end of follow-up). Adverse event data were collected at each of the follow-up visits (Day 7, Day 14, Day 28, Day 90, and Day 180).
At each of the follow-up visits (Day 7, Day 14, Day 28, Day 90, and Day 180), participants were asked about any adverse events that they might have experienced since their last visit. Clinical health assessments were conducted at every study visit, and included inquiry regarding any illness, any change in medication, and any overall health changes since the last study visit. Adverse event data was collected from enrollment until the end of follow-up at Day 180.
General disorders
Foot pain
1.7%
1/60 • Number of events 1 • 6 months Adverse event data were collected from Day 0 (enrollment) to Day 180 (the end of follow-up). Adverse event data were collected at each of the follow-up visits (Day 7, Day 14, Day 28, Day 90, and Day 180).
At each of the follow-up visits (Day 7, Day 14, Day 28, Day 90, and Day 180), participants were asked about any adverse events that they might have experienced since their last visit. Clinical health assessments were conducted at every study visit, and included inquiry regarding any illness, any change in medication, and any overall health changes since the last study visit. Adverse event data was collected from enrollment until the end of follow-up at Day 180.
Nervous system disorders
Bell's Palsy
1.7%
1/60 • Number of events 1 • 6 months Adverse event data were collected from Day 0 (enrollment) to Day 180 (the end of follow-up). Adverse event data were collected at each of the follow-up visits (Day 7, Day 14, Day 28, Day 90, and Day 180).
At each of the follow-up visits (Day 7, Day 14, Day 28, Day 90, and Day 180), participants were asked about any adverse events that they might have experienced since their last visit. Clinical health assessments were conducted at every study visit, and included inquiry regarding any illness, any change in medication, and any overall health changes since the last study visit. Adverse event data was collected from enrollment until the end of follow-up at Day 180.

Additional Information

Rafi Ahmed, PhD

Emory University

Phone: 404-727-3571

Results disclosure agreements

  • Principal investigator is a sponsor employee
  • Publication restrictions are in place