COVID-19, Influenza
Conditions
Keywords
Influenza, COVID-19, Immunogencity, Health, Reactogenicity
Brief summary
This is a prospective, randomized randomized immunologic study of response to influenza and SARS-CoV-2 vaccination across four of the US Influenza Vaccine Effectiveness (Flu VE) Network study sites.
Detailed description
This study is a prospective, randomized comparative immunogenicity study in an enrolled cohort. During this study, eligible participants will be randomly assigned to receive an approved quadrivalent cell culture-based influenza vaccine (ccIIV4, Seqirus) and an approved mRNA COVID-19 vaccine (Moderna) either concomitantly or sequentially, 28 days apart. Participants (aged 6-11 years and 18-64 years) will be enrolled in the 2023-2024 influenza season. Demographic and health data (including influenza and COVID-19 vaccination and infection history) will be collected upon enrollment. Enrolled participants will be randomized to one of the following interventions (2:1:1) (i) concomitant administration of the mRNA COVID-19 vaccine (Moderna) and quadrivalent influenza vaccine (ccIIV4, Seqirus); (ii)sequential administration of the quadrivalent influenza vaccine (ccIIV4, Seqirus) at Visit 1 (day 0) and the mRNA COVID-19 vaccine(Moderna) at Visit 2 (day 28); (iii) sequential administration of the mRNA COVID-19 vaccine (Moderna) at Visit 1 (day 0) followed by the quadrivalent influenza vaccine (ccIIV4, Seqirus) at Visit 2 (day 28). Participants will not be blinded to vaccine group. Whole blood samples to isolate sera for immune assays will be collected prior to vaccination administration at Visit 1 (day 0), Visit 2 (day 28) Visit 3 (day 56; post-vaccination 2) and Visit 4 (day180; end of local flu circulation). Blood samples to isolate PBMC and plasma will be collected from a subset of 250 participants (200 adults and 50 children). If participants exhibit ARI during the study period, the participants may be asked to present for collection of a nasal swab for viral testing for acute influenza or SARS-CoV-2 infection (within 10 days after symptom onset), and blood specimen to isolate sera for immune assays. For participants with confirmed acute infection, the participants may be asked to present for collection of a convalescent-phase blood specimen approximately 28 days after acute visit for isolation of sera, PBMC and plasma.
Interventions
BIOLOGICALSimultaneous Vaccination (Influenza Vaccine and mRNA COVID booster)
Influenza vaccination and mRNA COVID-19 booster will be given at Visit 1.
BIOLOGICALSequential Vaccination (Influenza vaccine then mRNA COVID booster)
Influenza vaccine will be given at Visit 1 and mRNA COVID booster will be given at Visit 2.
BIOLOGICALSequential Vaccination (mRNA COVID booster then Influenza vaccine)
mRNA COVID booster will be given at Visit 1 and Influenza vaccine will be given at Visit 2.
Sponsors
Centers for Disease Control and Prevention
Arizona State University
University Hospitals Cleveland Medical Center
University of Pittsburgh
Washington University School of Medicine
Valleywise Health
Cleveland VA Medical Center
Senders Pediatrics
Duke University
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
6 Years to 64 Years
Healthy volunteers
Yes
Inclusion criteria
* Healthy children aged 6-11 years and healthy adults aged 18-64 years that have not received the current season's influenza vaccination or a mRNA COVID-19 vaccination in the past 6 months and have already completed at least a two-dose primary series of an mRNA COVID-19 vaccination * English or Spanish literate * Email or text message capability for weekly follow-up * Intention of receiving influenza vaccine and mRNA COVID-19 vaccine based on ACIP-CDC guidelines * Willing to provide written/electronic informed consent * Intention of being available for entire study period and able to complete all relevant study procedures, including follow-up phone calls and clinic visits
Exclusion criteria
* Self-reported COVID-19 infection within 3 months prior to enrollment * Received COVID-19 vaccine within 6 months prior to enrollment * Received influenza vaccine during the respective influenza season in which the participants are being enrolled * \< 9 years of age and recommended to receive two doses of IIV4 during the respective influenza season in which they are being enrolled * History of severe allergic reaction after a previous dose of any influenza or COVID-19 mRNA vaccine; or to an influenza or COVID-19 mRNA vaccine component * Receipt of any licensed vaccine within 6 weeks prior to enrollment in this study or planning receipt of any vaccines within 4 weeks after the receipt of the second vaccine dose administered during study procedures * Has an immunocompromising condition or taking immunosuppressive medication\* \* Received oral, intramuscular or intravenous systemic immunosuppressants, or immune modifying drugs for \>14 days in total within 6 months prior to any study vaccine dose (for corticosteroids ≥ 20 mg/day of prednisone equivalent). \*\* Note: Topical medications are allowed * Received immunoglobulin, SARS-CoV-2 immunoglobulin, SARS-CoV-2 monoclonal antibody, or blood-derived products, within 3 months prior any study vaccine dose. * History of Guillain-Barré syndrome * History of myocarditis or pericarditis * History of multisystem inflammatory syndrome in children (MIS-C) or adults (MIS-A) * Currently pregnant, planning to become pregnant within the first three months of the study per participant self-report or likely to be pregnant per screening criteria * Bleeding disorder diagnosed by a healthcare provider or bleeding difficulties with intramuscular injections or blood draws. * Has injury or other reason why deltoid site on both arms cannot be used for vaccinations * Any condition which, in the opinion of the investigators, may pose a health risk to the participant or interfere with the evaluation of the study objectives * Temporary Delay Criteria: History of febrile illness (\> 100.0°F or 37.8°C) within the past 72 hours prior to vaccine administration
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Percentage of Participants With HAI Seroconversion | Visit 1 (day 1; baseline) to Visit 2 (days 28-42; post-vaccination) for all arms/groups | Number of participants with a seroconversion HAI Titer ≥1:40 at Day 29 if Day 1 titer is \<1:10 or a four-fold rise at Day 29 if Day 1 titer is ≥1:10 for each ccIIV4 antigen in the 2023-2024 influenza season. |
| Percentage of Participants With HAI Seroprotection | Visit 1 (day 1; baseline; pre-immunization) and Visit 2 (days 28-42; post-immunization) for all arms/groups | Number of participants with a seroprotective HAI titer (≥ 1:40) pre- and post-immunization at day 29 for each ccIIV4 antigen in the 2023-2024 influenza season. |
| HAI Geometric Mean Titer | Visit 1 (day 1; baseline; pre-immunization) and Visit 2 (days 28-42; post-immunization) for all arms/groups | The geometric mean HAI titer (GMT) for each ccIIV4 antigen in the 2023-2024 influenza season. GMTs were derived by using the anti-log of the mean of the log transformed titers. |
| HAI Geometric Mean Fold Rise (GMFR) | Visit 1 (day 1; baseline) to Visit 2 (days 28-42; post-vaccination) for all arms/groups | GMFRs and 95% confidence intervals were calculated using a t-distribution on log 2-transformed titers. |
Countries
United States
Participant flow
Pre-assignment details
455 participants were enrolled and consented. 8 participants were not randomized to a vaccine group due to being screen fails. 447 participants were randomized to Group i, Group ii, or Group iii.
Participants by arm
| Arm | Count |
|---|---|
| Group i: Concomitant Vaccination Simultaneous Vaccination (Influenza vaccine and mRNA COVID booster) at Visit 1
Simultaneous Vaccination (Influenza Vaccine and mRNA COVID booster): Influenza vaccination and mRNA COVID-19 booster will be given at Visit 1. | 223 |
| Group ii: Influenza Vaccination Sequential vaccination with Influenza vaccination at Visit 1 and mRNA COVID booster at Visit 2
Sequential Vaccination (Influenza vaccine then mRNA COVID booster): Influenza vaccine will be given at Visit 1 and mRNA COVID booster will be given at Visit 2. | 111 |
| Group Iii: mRNA COVID-19 Vaccination Sequential vaccination with mRNA COVID booster at Visit 1 and Influenza vaccination at Visit 2
Sequential Vaccination (mRNA COVID booster then Influenza vaccine): mRNA COVID booster will be given at Visit 1 and Influenza vaccine will be given at Visit 2. | 113 |
| Total | 447 |
Baseline characteristics
| Characteristic | Group i: Concomitant Vaccination | Total | Group Iii: mRNA COVID-19 Vaccination | Group ii: Influenza Vaccination |
|---|---|---|---|---|
| Age, Customized Age Group 18-49 Years | 174 Participants | 343 Participants | 84 Participants | 85 Participants |
| Age, Customized Age Group 50-64 Years | 43 Participants | 92 Participants | 26 Participants | 23 Participants |
| Age, Customized Age Group 6-11 Years | 5 Participants | 11 Participants | 3 Participants | 3 Participants |
| Age, Customized Age Group Unknown | 1 Participants | 1 Participants | 0 Participants | 0 Participants |
| Age, Customized Age (Years), Median | 33 Years | 33 Years | 34 Years | 32 Years |
| Enrollment Site Arizona State University | 66 Participants | 131 Participants | 33 Participants | 32 Participants |
| Enrollment Site Cleveland Veterans Affairs | 12 Participants | 23 Participants | 6 Participants | 5 Participants |
| Enrollment Site Senders Pediatrics | 1 Participants | 3 Participants | 1 Participants | 1 Participants |
| Enrollment Site University Hospitals Cleveland | 30 Participants | 60 Participants | 15 Participants | 15 Participants |
| Enrollment Site University of Pittsburgh | 77 Participants | 155 Participants | 39 Participants | 39 Participants |
| Enrollment Site Valleywise Health | 12 Participants | 25 Participants | 6 Participants | 7 Participants |
| Enrollment Site Washington University at St. Louis | 25 Participants | 50 Participants | 13 Participants | 12 Participants |
| Ethnicity (NIH/OMB) Hispanic or Latino | 37 Participants | 69 Participants | 16 Participants | 16 Participants |
| Ethnicity (NIH/OMB) Not Hispanic or Latino | 182 Participants | 371 Participants | 94 Participants | 95 Participants |
| Ethnicity (NIH/OMB) Unknown or Not Reported | 4 Participants | 7 Participants | 3 Participants | 0 Participants |
| Race (NIH/OMB) American Indian or Alaska Native | 0 Participants | 1 Participants | 1 Participants | 0 Participants |
| Race (NIH/OMB) Asian | 33 Participants | 64 Participants | 17 Participants | 14 Participants |
| Race (NIH/OMB) Black or African American | 12 Participants | 25 Participants | 7 Participants | 6 Participants |
| Race (NIH/OMB) More than one race | 7 Participants | 11 Participants | 0 Participants | 4 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 1 Participants | 1 Participants | 0 Participants | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 15 Participants | 28 Participants | 4 Participants | 9 Participants |
| Race (NIH/OMB) White | 155 Participants | 317 Participants | 84 Participants | 78 Participants |
| Sex: Female, Male Female | 135 Participants | 261 Participants | 65 Participants | 61 Participants |
| Sex: Female, Male Male | 84 Participants | 182 Participants | 48 Participants | 50 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk | EG002 affected / at risk |
|---|---|---|---|
| deaths Total, all-cause mortality | 0 / 223 | 0 / 111 | 0 / 113 |
| other Total, other adverse events | 0 / 0 | 0 / 0 | 0 / 0 |
| serious Total, serious adverse events | 0 / 223 | 0 / 111 | 0 / 113 |
Outcome results
Primary
HAI Geometric Mean Fold Rise (GMFR)
GMFRs and 95% confidence intervals were calculated using a t-distribution on log 2-transformed titers.
Time frame: Visit 1 (day 1; baseline) to Visit 2 (days 28-42; post-vaccination) for all arms/groups
Population: Influenza Immunogenicity Population: Subset of the mITT Population that includes only subjects who received both vaccines, provide visit 1 and visit 2 blood draws available with HAI titer results for analysis within the protocol-defined time frame, did not have an influenza or SARS-CoV-2 infection between visits 1 and 2, and had no protocol violations affecting immunogenicity.
| Arm | Measure | Group | Value (MEAN) |
|---|---|---|---|
| Group i | HAI Geometric Mean Fold Rise (GMFR) | A(H1N1)pdm09 | 4.7 Fold Change |
| Group i | HAI Geometric Mean Fold Rise (GMFR) | A(H3N2) | 2.8 Fold Change |
| Group i | HAI Geometric Mean Fold Rise (GMFR) | B/Victoria | 4.2 Fold Change |
| Group i | HAI Geometric Mean Fold Rise (GMFR) | B/Yamagata | 1.9 Fold Change |
| Group ii | HAI Geometric Mean Fold Rise (GMFR) | B/Yamagata | 1.7 Fold Change |
| Group ii | HAI Geometric Mean Fold Rise (GMFR) | A(H1N1)pdm09 | 4.4 Fold Change |
| Group ii | HAI Geometric Mean Fold Rise (GMFR) | B/Victoria | 4.1 Fold Change |
| Group ii | HAI Geometric Mean Fold Rise (GMFR) | A(H3N2) | 3.2 Fold Change |
| Group Iii | HAI Geometric Mean Fold Rise (GMFR) | B/Yamagata | 1.0 Fold Change |
| Group Iii | HAI Geometric Mean Fold Rise (GMFR) | A(H3N2) | 1.0 Fold Change |
| Group Iii | HAI Geometric Mean Fold Rise (GMFR) | B/Victoria | 1.1 Fold Change |
| Group Iii | HAI Geometric Mean Fold Rise (GMFR) | A(H1N1)pdm09 | 1.0 Fold Change |
Comparison: Antigen: A(H1N1)pdm09p-value: 0.793Regression, Linear
Comparison: Antigen: A(H3N2)p-value: 0.326Regression, Linear
Comparison: Antigen: B/Victoriap-value: 0.933Regression, Linear
Comparison: Antigen: B/Yamagatap-value: 0.424Regression, Linear
Comparison: Antigen: A(H1N1)pdm09p-value: <0.001Regression, Linear
Comparison: Antigen: A(H3N2)p-value: <0.001Regression, Linear
Comparison: Antigen: B/Victoriap-value: <0.001Regression, Linear
Comparison: Antigen: B/Yamagatap-value: <0.001Regression, Linear
Primary
HAI Geometric Mean Titer
The geometric mean HAI titer (GMT) for each ccIIV4 antigen in the 2023-2024 influenza season. GMTs were derived by using the anti-log of the mean of the log transformed titers.
Time frame: Visit 1 (day 1; baseline; pre-immunization) and Visit 2 (days 28-42; post-immunization) for all arms/groups
Population: Influenza Immunogenicity Population: Subset of the mITT Population that includes only subjects who received both vaccines, provide visit 1 and visit 2 blood draws available with HAI titer results for analysis within the protocol-defined time frame, did not have an influenza or SARS-CoV-2 infection between visits 1 and 2, and had no protocol violations affecting immunogenicity.
| Arm | Measure | Group | Value (GEOMETRIC_MEAN) |
|---|---|---|---|
| Group i | HAI Geometric Mean Titer | Pre-vaccine: A(H1N1)pdm09 | 31.7 Titer |
| Group i | HAI Geometric Mean Titer | Post-vaccine: A(H1N1)pdm09 | 148.3 Titer |
| Group i | HAI Geometric Mean Titer | Pre-vaccine: A(H3N2) | 20.9 Titer |
| Group i | HAI Geometric Mean Titer | Post-vaccine: A(H3N2) | 58.5 Titer |
| Group i | HAI Geometric Mean Titer | Pre-vaccine: B/Victoria | 24.9 Titer |
| Group i | HAI Geometric Mean Titer | Post-vaccine: B/Victoria | 103.8 Titer |
| Group i | HAI Geometric Mean Titer | Pre-vaccine: B/Yamagata | 119.3 Titer |
| Group i | HAI Geometric Mean Titer | Post-vaccine: B/Yamagata | 223.9 Titer |
| Group ii | HAI Geometric Mean Titer | Pre-vaccine: A(H3N2) | 22.5 Titer |
| Group ii | HAI Geometric Mean Titer | Pre-vaccine: B/Yamagata | 143.4 Titer |
| Group ii | HAI Geometric Mean Titer | Post-vaccine: A(H3N2) | 72.0 Titer |
| Group ii | HAI Geometric Mean Titer | Pre-vaccine: B/Victoria | 29.3 Titer |
| Group ii | HAI Geometric Mean Titer | Post-vaccine: B/Victoria | 120.4 Titer |
| Group ii | HAI Geometric Mean Titer | Pre-vaccine: A(H1N1)pdm09 | 33.6 Titer |
| Group ii | HAI Geometric Mean Titer | Post-vaccine: A(H1N1)pdm09 | 146.6 Titer |
| Group ii | HAI Geometric Mean Titer | Post-vaccine: B/Yamagata | 245.2 Titer |
| Group Iii | HAI Geometric Mean Titer | Pre-vaccine: A(H3N2) | 21.3 Titer |
| Group Iii | HAI Geometric Mean Titer | Post-vaccine: A(H1N1)pdm09 | 34.5 Titer |
| Group Iii | HAI Geometric Mean Titer | Pre-vaccine: A(H1N1)pdm09 | 34.1 Titer |
| Group Iii | HAI Geometric Mean Titer | Post-vaccine: A(H3N2) | 21.7 Titer |
| Group Iii | HAI Geometric Mean Titer | Pre-vaccine: B/Yamagata | 107.4 Titer |
| Group Iii | HAI Geometric Mean Titer | Post-vaccine: B/Victoria | 24.4 Titer |
| Group Iii | HAI Geometric Mean Titer | Pre-vaccine: B/Victoria | 22.0 Titer |
| Group Iii | HAI Geometric Mean Titer | Post-vaccine: B/Yamagata | 110.6 Titer |
Comparison: Pre-vaccine: Antigen A(H1N1)pdm09p-value: 0.699Regression, Linear
Comparison: Post-vaccine: Antigen A(H1N1)pdm09p-value: 0.88Regression, Linear
Comparison: Pre-vaccine: Antigen A(H3N2)p-value: 0.72Regression, Linear
Comparison: Post-vaccine: Antigen A(H3N2)p-value: 0.238Regression, Linear
Comparison: Pre-vaccine: Antigen B/Victoriap-value: 0.28Regression, Linear
Comparison: Post-vaccine: Antigen B/Victoriap-value: 0.094Regression, Linear
Comparison: Pre-vaccine: Antigen B/Yamagatap-value: 0.216Regression, Linear
Comparison: Post-vaccine: Antigen B/Yamagatap-value: 0.436Regression, Linear
Comparison: Pre-vaccine: Antigen A(H1N1)pdm09p-value: 0.615Regression, Linear
Comparison: Post-vaccine: Antigen A(H1N1)pdm09p-value: <0.001Regression, Linear
Comparison: Pre-vaccine: Antigen A(H3N2)p-value: 0.87Regression, Linear
Comparison: Post-vaccine: Antigen A(H3N2)p-value: <0.001Regression, Linear
Comparison: Pre-vaccine: Antigen B/Victoriap-value: 0.64Regression, Linear
Comparison: Post-vaccine: Antigen B/Victoriap-value: <0.001Regression, Linear
Comparison: Pre-vaccine: Antigen B/Yamagatap-value: 0.444Regression, Linear
Comparison: Post-vaccine: Antigen B/Yamagatap-value: <0.001Regression, Linear
Primary
Percentage of Participants With HAI Seroconversion
Number of participants with a seroconversion HAI Titer ≥1:40 at Day 29 if Day 1 titer is \<1:10 or a four-fold rise at Day 29 if Day 1 titer is ≥1:10 for each ccIIV4 antigen in the 2023-2024 influenza season.
Time frame: Visit 1 (day 1; baseline) to Visit 2 (days 28-42; post-vaccination) for all arms/groups
Population: Influenza Immunogenicity Population: Subset of the modified intention-to-treat (mITT) Population that includes only subjects who received both vaccines, provide visit 1 and visit 2 blood draws available with HAI titer results for analysis within the protocol-defined time frame, did not have an influenza or SARS-CoV-2 infection between visits 1 and 2, and had no protocol violations affecting immunogenicity.
| Arm | Measure | Group | Value (NUMBER) |
|---|---|---|---|
| Group i | Percentage of Participants With HAI Seroconversion | A(H3N2) | 33.5 percentage of participants |
| Group i | Percentage of Participants With HAI Seroconversion | A(H1N1)pdm09 | 53.3 percentage of participants |
| Group i | Percentage of Participants With HAI Seroconversion | B/Yamagata | 18.8 percentage of participants |
| Group i | Percentage of Participants With HAI Seroconversion | B/Victoria | 47.7 percentage of participants |
| Group ii | Percentage of Participants With HAI Seroconversion | A(H1N1)pdm09 | 52.6 percentage of participants |
| Group ii | Percentage of Participants With HAI Seroconversion | B/Yamagata | 14.7 percentage of participants |
| Group ii | Percentage of Participants With HAI Seroconversion | B/Victoria | 48.4 percentage of participants |
| Group ii | Percentage of Participants With HAI Seroconversion | A(H3N2) | 36.8 percentage of participants |
| Group Iii | Percentage of Participants With HAI Seroconversion | B/Yamagata | 1.9 percentage of participants |
| Group Iii | Percentage of Participants With HAI Seroconversion | B/Victoria | 4.7 percentage of participants |
| Group Iii | Percentage of Participants With HAI Seroconversion | A(H3N2) | 1.9 percentage of participants |
| Group Iii | Percentage of Participants With HAI Seroconversion | A(H1N1)pdm09 | 0.9 percentage of participants |
Comparison: Antigen: A(H1N1)pdm09p-value: 0.938Regression, Logistic
Comparison: Antigen: A(H3N2)p-value: 0.451Regression, Logistic
Comparison: Antigen: B/Victoriap-value: 0.819Regression, Logistic
Comparison: Antigen: B/Yamagatap-value: 0.5Regression, Logistic
Comparison: Antigen: A(H1N1)pdm09p-value: <0.001Regression, Logistic
Comparison: Antigen: A(H3N2)p-value: 0.001Regression, Logistic
Comparison: Antigen: B/Victoriap-value: <0.001Regression, Logistic
Comparison: Antigen: B/Yamagatap-value: <0.001Regression, Logistic
Primary
Percentage of Participants With HAI Seroprotection
Number of participants with a seroprotective HAI titer (≥ 1:40) pre- and post-immunization at day 29 for each ccIIV4 antigen in the 2023-2024 influenza season.
Time frame: Visit 1 (day 1; baseline; pre-immunization) and Visit 2 (days 28-42; post-immunization) for all arms/groups
Population: Influenza Immunogenicity Population: Subset of the mITT Population that includes only subjects who received both vaccines, provide visit 1 and visit 2 blood draws available with HAI titer results for analysis within the protocol-defined time frame, did not have an influenza or SARS-CoV-2 infection between visits 1 and 2, and had no protocol violations affecting immunogenicity.
| Arm | Measure | Group | Value (NUMBER) |
|---|---|---|---|
| Group i | Percentage of Participants With HAI Seroprotection | A(H1N1)pdm09 | 88.3 percentage of participants |
| Group i | Percentage of Participants With HAI Seroprotection | A(H3N2) | 71.1 percentage of participants |
| Group i | Percentage of Participants With HAI Seroprotection | B/Victoria | 84.3 percentage of participants |
| Group i | Percentage of Participants With HAI Seroprotection | B/Yamagata | 95.4 percentage of participants |
| Group ii | Percentage of Participants With HAI Seroprotection | B/Yamagata | 97.9 percentage of participants |
| Group ii | Percentage of Participants With HAI Seroprotection | A(H1N1)pdm09 | 87.4 percentage of participants |
| Group ii | Percentage of Participants With HAI Seroprotection | B/Victoria | 85.3 percentage of participants |
| Group ii | Percentage of Participants With HAI Seroprotection | A(H3N2) | 80.0 percentage of participants |
| Group Iii | Percentage of Participants With HAI Seroprotection | B/Yamagata | 87.8 percentage of participants |
| Group Iii | Percentage of Participants With HAI Seroprotection | A(H3N2) | 36.5 percentage of participants |
| Group Iii | Percentage of Participants With HAI Seroprotection | B/Victoria | 38.3 percentage of participants |
| Group Iii | Percentage of Participants With HAI Seroprotection | A(H1N1)pdm09 | 58.9 percentage of participants |
Comparison: Antigen: A(H1N1)pdm09p-value: 0.894Regression, Logistic
Comparison: Antigen: A(H3N2)p-value: 0.104Regression, Logistic
Comparison: Antigen: B/Victoriap-value: 0.815Regression, Logistic
Comparison: Antigen: B/Yamagatap-value: 0.814Regression, Logistic
Comparison: Antigen: A(H1N1)pdm09p-value: <0.001Regression, Logistic
Comparison: Antigen: A(H3N2)p-value: <0.001Regression, Logistic
Comparison: Antigen: B/Victoriap-value: <0.001Regression, Logistic
Comparison: Antigen: B/Yamagatap-value: <0.001Regression, Logistic