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Intramuscular injection

Intramuscular injection

Intramuscular injection

Intramuscular injection

Intramuscular injection

Systemic events included fever, vomiting, diarrhea, headache, fatigue, chills, new/worsened muscle pain & new /worsened joint pain & recorded by participants in electronic diary. Fever defined as oral temperature >=38.0 deg C & categorized as >=38.0 to 38.4 deg C, >38.4 to 38.9 deg C, >38.9 to 40.0 deg C & >40.0 deg C. Vomiting graded as: Grade(G) 1: 1-2 times in 24 h; G2: >2 times in 24 h; G3: required IV hydration. Diarrhea graded as: G1: 2-3 loose stools in 24 h; G2: 4-5 loose stools in 24 h; G3: 6 or more loose stools in 24 h. Headache, fatigue, chills, new/worsened muscle pain & new/worsened joint pain: G1: didn't interfere with activity; G2: some interference with activity; G3: prevented daily routine activity. For all systemic events except fever, Grade 4= emergency room visit or hospitalization. Grade 4 events were classified by the investigator or medically qualified person. Exact 2-sided confidence interval based on Clopper and Pearson method.

An adverse event (AE) was defined as any untoward medical occurrence in a participant temporally associated with the use of study intervention, whether or not considered related to the study intervention. Exact 2-sided 95% CI was based on the Clopper and Pearson method. Only AEs collected by non-systematic assessment (i.e, excluding local reactions and systematic events) were reported in this outcome measure.

An AE was defined as any untoward medical occurrence in a participant temporally associated with the use of study intervention, whether or not considered related to the study intervention. Exact 2-sided 95% CI was based on the Clopper and Pearson method. Only AEs collected by non-systematic assessment (i.e. excluding local reactions and systemic events) were reported in this outcome measure.

An SAE was defined as any untoward medical occurrence that, at any dose, met one or more of the following criteria - resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, was a congenital anomaly/birth defect and was a suspected transmission via a Pfizer product of an infectious agent, pathogenic or non-pathogenic and other important medical event.

Hematology parameters included erythrocytes, lymphocytes, neutrophils, eosinophils/leukocytes, erythrocyte (ery) mean corpuscular volume, ery. mean corpuscular hemoglobin and ery. mean corpuscular hemoglobin concentration. The primary criteria were as follows erythrocytes, lymphocytes, neutrophils: <0.8*lower limit of normal (LLN); Lymphocytes/Leukocytes, Eosinophils/Leukocytes, Monocytes/Leukocytes: >1.2*upper limit of normal (ULN); Ery. Mean Corpuscular Volume:>1.1*ULN; Ery. Mean Corpuscular Hemoglobin and Ery.Mean Corpuscular hemoglobin Concentration: < 0.9*LLN. Also add 95% CI was based on Clopper and Pearson method.

Hematology parameters included erythrocytes, neutrophils, eosinophils/leukocytes, monocytes/leukocytes, ery mean corpuscular hemoglobin. The primary criteria were as follows erythrocytes and neutrophils: <0.8* LLN; Eosinophils/Leukocytes and Monocytes/Leukocytes: >1.2* ULN; Ery. Mean Corpuscular Hemoglobin:>1.1*ULN. 95% CI was based on Clopper and Pearson method.

Chemistry parameters included blood urea nitrogen and C-reactive protein. The primary criteria were as follows Blood Urea Nitrogen: > 1.3*ULN; C Reactive Protein: > 1.1*ULN. 95% CI was based on Clopper and Pearson method.

Chemistry parameters included blood urea nitrogen and C-reactive protein. The primary criteria were as follows Blood Urea Nitrogen: > 1.3*ULN; C Reactive Protein: > 1.1*ULN. Also add 95% CI was based on Clopper and Pearson method.

Hematology parameters included hemoglobin, lymphocytes, neutrophils decrease, platelets decrease, white blood cells (WBC) decrease and WBC increase. Laboratory abnormalities were graded by Food and Drug Administration (FDA) toxicity grading scale for healthy adult volunteers enrolled in preventive vaccine clinical trials as grade 1=mild; grade 2=moderate; grade 3=severe and grade 4=potentially life-threatening. Percentage of participants with shift in hematology values were reported in this outcome measure. Categories with at least 1 non-zero data values showing any shift in Grade from baseline to 2 days after vaccination 1 were reported. Participants whose grade category was unchanged (e.g. normal to normal) were not reported.

Hematology parameters included hemoglobin, lymphocytes, neutrophils decrease, WBC decrease and WBC increase. Laboratory abnormalities were graded by FDA toxicity grading scale for healthy adult volunteers enrolled in preventive vaccine clinical trials as grade 1=mild; grade 2=moderate; grade 3=severe and grade 4=potentially life-threatening. Percentage of participants with shift in hematology values were reported in this outcome measure. Categories with at least 1 non-zero data values showing any shift in Grade from baseline to 1 week after vaccination 1 were reported. Participants whose grade category was unchanged (e.g. normal to normal) were not reported.

Chemistry abnormalities were graded by toxicity grading scale for healthy adult volunteers enrolled in preventive vaccine clinical trials as grade 1=mild; grade 2=moderate; grade 3=severe and grade 4=potentially life-threatening. Percentage of participants with shift in chemistry values were reported in this outcome measure. Categories with at least 1 non-zero data values showing any shift in Grade from baseline to 2 days after vaccination 1 (post-baseline) were reported. Participants whose grade category was unchanged (e.g. normal to normal) were not reported. The parameters reported were - Alanine Aminotransferase Increased (ALP), Alkaline Phosphatase Increased (ALP), Aspartate Aminotransferase Increased (AST), Creatinine Increased and Urea Nitrogen.

Chemistry abnormalities were graded by toxicity grading scale for healthy adult volunteers enrolled in preventive vaccine clinical trials as grade 1=mild; grade 2=moderate; grade 3=severe and grade 4=potentially life-threatening. Percentage of participants with shift in chemistry values were reported in this outcome measure. Categories with at least 1 non-zero data values showing any shift in Grade from baseline to 1 week after vaccination 1 (post-baseline) were reported. Participants whose grade category was unchanged (e.g. normal to normal) were not reported. The parameters reported were - Alanine Aminotransferase Increased, Alkaline Phosphatase Increased, Aspartate Aminotransferase Increased, Creatinine Increased and Urea Nitrogen.

An ECG abnormality was defined as any new abnormality that, as judged by a cardiologist, was consistent with probable or possible myocarditis or pericarditis, including: Sustained atrial or ventricular arrhythmias, Second-degree Mobitz Type II or worse atrioventricular block, new bundle branch block and Diffuse ST-segment elevation or PR-segment inversion, compatible with pericarditis.

An ECG abnormality was defined as any new abnormality that, as judged by a cardiologist, was consistent with probable or possible myocarditis or pericarditis, including: Sustained atrial or ventricular arrhythmias, Second-degree Mobitz Type II or worse atrioventricular block, new bundle branch block and Diffuse ST-segment elevation or PR-segment inversion, compatible with pericarditis.

Local reactions included pain at the injection site, redness and swelling and were recorded by participants in an electronic diary. Redness and swelling were measured and recorded in measuring device units, where 1 measuring device unit=0.5 cm. Redness and swelling were graded as mild (Grade 1): >2.0 cm to 5.0 cm; moderate (Grade 2): >5.0 cm to 10.0 cm; severe (Grade 3): >10 cm; potentially life-threatening (Grade 4): necrosis or exfoliative dermatitis. Pain at injection site was graded as mild (Grade 1): did not interfere with activity; moderate (Grade 2): interfered with activity; severe (Grade 3): prevented daily activity and potentially life-threatening (Grade 4): emergency room visit or hospitalization for severe pain. Exact 2-sided confidence interval was based on the Clopper and Pearson method.

Local reactions included pain at the injection site, redness and swelling and were recorded by participants in an electronic diary. Redness and swelling were measured and recorded in measuring device units, where 1 measuring device unit=0.5 cm. Redness and swelling were graded as mild (Grade 1): >2.0 cm to 5.0 cm; moderate (Grade 2): >5.0 cm to 10.0 cm; severe (Grade 3): >10 cm; potentially life-threatening (Grade 4): necrosis or exfoliative dermatitis. Pain at injection site was graded as mild (Grade 1): did not interfere with activity; moderate (Grade 2): interfered with activity; severe (Grade 3): prevented daily activity and potentially life-threatening (Grade 4): emergency room visit or hospitalization for severe pain. Exact 2-sided confidence interval was based on the Clopper and Pearson method.

Local reactions included pain at the injection site, redness and swelling and were recorded by participants in an electronic diary. Redness and swelling were measured and recorded in measuring device units, where 1 measuring device unit=0.5 cm. Redness and swelling were graded as mild (Grade 1): >2.0 cm to 5.0 cm; moderate (Grade 2): >5.0 cm to 10.0 cm; severe (Grade 3): >10 cm; potentially life-threatening (Grade 4): necrosis or exfoliative dermatitis. Pain at injection site was graded as mild (Grade 1): did not interfere with activity; moderate (Grade 2): interfered with activity; severe (Grade 3): prevented daily activity and potentially life-threatening (Grade 4): emergency room visit or hospitalization for severe pain. Exact 2-sided confidence interval was based on the Clopper and Pearson method.

Local reactions included pain at the injection site, redness and swelling and were recorded by participants in an electronic diary. Redness and swelling were measured and recorded in measuring device units, where 1 measuring device unit=0.5 cm. Redness and swelling were graded as mild (Grade 1): >2.0 cm to 5.0 cm; moderate (Grade 2): >5.0 cm to 10.0 cm; severe (Grade 3): >10 cm; potentially life-threatening (Grade 4): necrosis or exfoliative dermatitis. Pain at injection site was graded as mild (Grade 1): did not interfere with activity; moderate (Grade 2): interfered with activity; severe (Grade 3): prevented daily activity and potentially life-threatening (Grade 4): emergency room visit or hospitalization for severe pain. Exact 2-sided confidence interval was based on the Clopper and Pearson method.

Systemic events included fever, vomiting, diarrhea, headache, fatigue, chills, new/worsened muscle pain & new /worsened joint pain & recorded by participants in electronic diary. Fever defined as oral temperature >=38.0 deg C & categorized as >=38.0 to 38.4 deg C, >38.4 to 38.9 deg C, >38.9 to 40.0 deg C & >40.0 deg C. Vomiting graded as: G 1: 1-2 times in 24 hrs; G 2: >2 times in 24 hrs; G 3: required IV hydration; G 4: emergency room visit/ hospitalization for hypotensive shock. Diarrhea graded as: G 1: 2-3 loose stools in 24 hrs; G 2: 4-5 loose stools in 24 hrs; G 3: 6 or more loose stools in 24 hrs & G 4: emergency room visit/ hospitalization. Headache, fatigue, chills, new/worsened muscle pain & new/worsened joint pain: G 1: didn't interfere with activity; G 2: some interference with activity; G 3: prevented daily routine activity & G 4: emergency room visit/ hospitalization. Exact 2-sided confidence interval based on Clopper and Pearson method.

Systemic events included fever, vomiting, diarrhea, headache, fatigue, chills, new/worsened muscle pain & new /worsened joint pain & recorded by participants in electronic diary. Fever defined as oral temperature >=38.0 deg C & categorized as >=38.0 to 38.4 deg C, >38.4 to 38.9 deg C, >38.9 to 40.0 deg C & >40.0 deg C. Vomiting graded as: G 1: 1-2 times in 24 hrs; G 2: >2 times in 24 hrs; G 3: required IV hydration; G 4: emergency room visit/ hospitalization for hypotensive shock. Diarrhea graded as: G 1: 2-3 loose stools in 24 hrs; G 2: 4-5 loose stools in 24 hrs; G 3: 6 or more loose stools in 24 hrs & G 4: emergency room visit/ hospitalization. Headache, fatigue, chills, new/worsened muscle pain & new/worsened joint pain: G 1: didn't interfere with activity; G 2: some interference with activity; G 3: prevented daily routine activity & G 4: emergency room visit/ hospitalization. Exact 2-sided confidence interval based on Clopper and Pearson method.

Systemic events included fever, vomiting, diarrhea, headache, fatigue, chills, new/worsened muscle pain & new /worsened joint pain & recorded by participants in electronic diary. Fever defined as oral temperature >=38.0 deg C & categorized as >=38.0 to 38.4 deg C, >38.4 to 38.9 deg C, >38.9 to 40.0 deg C & >40.0 deg C. Vomiting graded as: G 1: 1-2 times in 24 hrs; G 2: >2 times in 24 hrs; G 3: required IV hydration; G 4: emergency room visit/ hospitalization for hypotensive shock. Diarrhea graded as: G: 1: 2-3 loose stools in 24 hrs; G 2: 4-5 loose stools in 24 hrs; G 3: 6 or more loose stools in 24 hrs & G 4: emergency room visit/ hospitalization. Headache, fatigue, chills, new/worsened muscle pain & new/worsened joint pain: G 1: didn't interfere with activity; G 2: some interference with activity; G 3: prevented daily routine activity & G 4: emergency room visit/ hospitalization. Exact 2-sided confidence interval based on Clopper and Pearson method.

Systemic events included fever, vomiting, diarrhea, headache, fatigue, chills, new/worsened muscle pain & new /worsened joint pain & recorded by participants in electronic diary. Fever defined as oral temperature >=38.0 deg C & categorized as >=38.0 to 38.4 deg C, >38.4 to 38.9 deg C, >38.9 to 40.0 deg C & >40.0 deg C. Vomiting graded as: G 1: 1-2 times in 24 hrs; G 2: >2 times in 24 hrs; G 3: required IV hydration; G 4: emergency room visit/ hospitalization for hypotensive shock. Diarrhea graded as: G 1: 2-3 loose stools in 24 hrs; G 2: 4-5 loose stools in 24 hrs; G 3: 6 or more loose stools in 24 hrs & G 4: emergency room visit/ hospitalization. Headache, fatigue, chills, new/worsened muscle pain & new/worsened joint pain: G 1: didn't interfere with activity; G 2: some interference with activity; G 3: prevented daily routine activity & G 4: emergency room visit/ hospitalization. Exact 2-sided confidence interval based on Clopper and Pearson method.

An AE was defined as any untoward medical occurrence in a participant temporally associated with the use of study intervention, whether or not considered related to the study intervention. Only AEs collected by non-systematic assessment (i.e, excluding local reactions and systematic events) were reported in this outcome measure.

An SAE was defined as any untoward medical occurrence that, at any dose, met one or more of the following criteria - resulted in death, was life-threatening, required inpatient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, was a congenital anomaly/birth defect and was a suspected transmission via a Pfizer product of an infectious agent, pathogenic or non-pathogenic and other important medical event.

Percentage of participants reporting abnormal troponin I laboratory values 2 days after vaccination 1 were reported in this outcome measure.

Percentage of participants reporting abnormal troponin I laboratory values 2 days after vaccination 2 were reported in this outcome measure.

Percentage of participants reporting abnormal troponin I laboratory values 2 days after vaccination were reported in this outcome measure.

Percentage of participants reporting abnormal troponin I laboratory values 2 days after vaccination were reported in this outcome measure.

Twelve lead ECGs were performed after the participant had rested quietly for at least 10 minutes in a supine position. An ECG abnormality was defined as any new abnormality that, as judged by a cardiologist, was consistent with probable or possible myocarditis or pericarditis, including: Sustained atrial or ventricular arrhythmias, Second-degree Mobitz Type II or worse atrioventricular block, new bundle branch block and Diffuse ST-segment elevation or PR-segment inversion, compatible with pericarditis.

Twelve lead ECGs were performed after the participant had rested quietly for at least 10 minutes in a supine position. An ECG abnormality was defined as any new abnormality that, as judged by a cardiologist, was consistent with probable or possible myocarditis or pericarditis, including: Sustained atrial or ventricular arrhythmias, Second-degree Mobitz Type II or worse atrioventricular block, new bundle branch block and Diffuse ST-segment elevation or PR-segment inversion, compatible with pericarditis.

Twelve lead ECGs were performed after the participant had rested quietly for at least 10 minutes in a supine position. An ECG abnormality was defined as any new abnormality that, as judged by a cardiologist, was consistent with probable or possible myocarditis or pericarditis, including: Sustained atrial or ventricular arrhythmias, Second-degree Mobitz Type II or worse atrioventricular block, new bundle branch block and Diffuse ST-segment elevation or PR-segment inversion, compatible with pericarditis.

Twelve lead ECGs were performed after the participant had rested quietly for at least 10 minutes in a supine position. An ECG abnormality was defined as any new abnormality that, as judged by a cardiologist, was consistent with probable or possible myocarditis or pericarditis, including: Sustained atrial or ventricular arrhythmias, Second-degree Mobitz Type II or worse atrioventricular block, new bundle branch block and Diffuse ST-segment elevation or PR-segment inversion, compatible with pericarditis.

Geometric mean fold rise (GMFR) was defined as ratios of the results after vaccination to the results before vaccination. GMFRs and the corresponding 2-sided 95% CIs were calculated by exponentiating the mean logarithm of the fold rises and the corresponding CIs (based on the Student t distribution). Assay results below the LLOQ were set to 0.5*LLOQ. When prevaccination assay results were lower than the LLOQ and the postvaccination results were greater than or equal to the LLOQ, the prevaccination assay results were set to LLOQ for the GMFR calculation.

Seroconversion was defined as an HAI titer <1:10 prior to vaccination and >=1:40 at the time point of interest, or an HAI titer of >=1:10 prior to vaccination with a 4-fold rise at the time point of interest. Exact 2-sided 95% CI was based on the Clopper and Pearson method.

Percentage of participants with HAI titer >=1:40 for each strain before vaccination 1 and at 1, 4 and 8 weeks after vaccination 1 is presented in this outcome measure. Exact 2-sided 95% CI was based on the Clopper and Pearson method.

Seroconversion was defined as an HAI titer <1:10 prior to vaccination and >=1:40 at the time point of interest, or an HAI titer of >=1:10 prior to vaccination with a 4-fold rise at the time point of interest. Exact 2-sided 95% CI was based on the Clopper and Pearson method.

Percentage of participants with HAI titer >=1:40 for all strains before vaccination 1 and 1, 4 and 8 weeks after vaccination 1 is presented in this outcome measure. Exact 2-sided 95% CI was based on the Clopper and Pearson method.

GMTs and 2-sided 95% CIs were calculated by exponentiating the mean logarithm of the concentrations and the corresponding CIs (based on the Student t distribution) and were reported in the descriptive section. GMRs were estimated by the ratio of the GMTs between vaccine groups, using licensed QIV group as reference and were reported in the statistical analysis section.

Seroconversion was defined as an HAI titer <1:10 prior to vaccination and >=1:40 at the time point of interest, or an HAI titer of >=1:10 prior to vaccination with a 4-fold rise at the time point of interest. Percentage of participants achieving seroconversion for each strain at 4 weeks after vaccination 1 and exact 2-sided 95% CI based on the Clopper and Pearson method is presented in the descriptive section. Difference in percentage of participants achieving HAI seroconversion for each strain at 4 weeks after vaccination 1 is presented in the statistical analysis section.

GMTs and 2-sided 95% CIs were calculated by exponentiating the mean logarithm of the concentrations and the corresponding CIs (based on the Student t distribution). Assay results below the LLOQ were set to 0.5*LLOQ.

GMTs and 2-sided 95% CIs were calculated by exponentiating the mean logarithm of the concentrations and the corresponding CIs (based on the Student t distribution). Assay results below the LLOQ were set to 0.5 × LLOQ.

GMFRs and the corresponding 2-sided 95% CIs were calculated by exponentiating the mean logarithm of the fold rises and the corresponding CIs (based on the Student t distribution). Assay results below the LLOQ were set to 0.5* LLOQ. When prevaccination assay results were lower than the LLOQ and the postvaccination results were greater than or equal to the LLOQ, the prevaccination assay results were set to LLOQ for the GMFR calculation.

GMFRs and the corresponding 2-sided 95% CIs were calculated by exponentiating the mean logarithm of the fold rises and the corresponding CIs (based on the Student t distribution). Assay results below the LLOQ were set to 0.5*LLOQ. When prevaccination assay results were lower than the LLOQ and the postvaccination results were greater than or equal to the LLOQ, the prevaccination assay results were set to LLOQ for the GMFR calculation.

Seroconversion was defined as an HAI titer <1:10 prior to vaccination and >=1:40 at the time point of interest, or an HAI titer >=1:10 prior to vaccination with a 4-fold rise at the time point of interest. Exact 2-sided CI was based on the Clopper and Pearson method.

Seroconversion was defined as an HAI titer<1:10 prior to vaccination and>=1:40 at the time point of interest,or an HAI titer>=1:10 prior to vaccination with a 4-fold rise at the time point of interest.Exact 2-sided CI was based on the Clopper and Pearson method.

Proportion of participants achieving HAI titers >= 1:40 for each strain before vaccination and at 1, 4 and 8 weeks after vaccination is reported in this outcome measure. Exact 2-sided CI was based on the Clopper and Pearson method.

Percentage of participants achieving HAI titers >= 1:40 for each strain before vaccinations 1 and 2 and at 1, 4 and 8 weeks after last vaccination is reported in this outcome measure. Exact 2-sided CI was based on the Clopper and Pearson method.

Seroconversion was defined as an HAI titer<1:10 prior to vaccination and>=1:40 at the time point of interest,or an HAI titer>=1:10 prior to vaccination with a 4-fold rise at the time point of interest. Exact 2-sided CI was based on the Clopper and Pearson method.

Seroconversion was defined as an HAI titer<1:10 prior to vaccination and>=1:40 at the time point of interest,or an HAI titer>=1:10 prior to vaccination with a 4-fold rise at the time point of interest. Exact 2-sided CI was based on the Clopper and Pearson method.

Percentage of participants with HAI titers >=1:40 for all strains before vaccinations 1 and 2 and 1, 4, and 8 weeks after the last vaccination is reported in this outcome measure. Exact 2-sided CI was based on the Clopper and Pearson method.

Percentage of participants with HAI titers >=1:40 for all strains before vaccinations 1 and 2 and 1, 4, and 8 weeks after the last vaccination is reported in this outcome measure. Exact 2-sided CI was based on the Clopper and Pearson method.

HAI GMT before vaccination and at 1, 4, and 8 weeks after vaccination was described in this outcome measure. GMTs and the corresponding 2-sided CIs were calculated by exponentiating the mean logarithm of the titers and the corresponding CIs (based on Student's t distribution).

GMFRs and the corresponding 2-sided 95% CIs were calculated by exponentiating the mean logarithm of the fold rises and the corresponding CIs (based on the Student t distribution). Assay results below the LLOQ were set to 0.5*LLOQ. When prevaccination assay results were lower than the LLOQ and the postvaccination results were greater than or equal to the LLOQ, the pre vaccination assay results were set to LLOQ for the GMFR calculation.

Seroconversion was defined as an HAI titer<1:10 prior to vaccination and>=1:40 at the time point of interest,or an HAI titer>=1:10 prior to vaccination with a 4-fold rise at the time point of interest. Exact 2-sided CI was based on the Clopper and Pearson method.

Percentage of participants with HAI titers >=1:40 for each strain before vaccination and 1, 4, and 8 weeks after vaccination is reported in this outcome measure. Exact 2-sided CI was based on the Clopper and Pearson method.

Seroconversion was defined as an HAI titer<1:10 prior to vaccination and>=1:40 at the time point of interest,or an HAI titer>=1:10 prior to vaccination with a 4-fold rise at the time point of interest. Exact 2-sided CI was based on the Clopper and Pearson method.

Percentage of participants with HAI titers >=1:40 for all strains before vaccination and 1, 4, and 8 weeks after vaccination is reported in this outcome measure. Exact 2-sided CI was based on the Clopper and Pearson method.

Participants received a single injection of mIRV encoding A strain at dose level 2, intramuscularly into the deltoid muscle at Day 1. Following unblinding at 8 weeks after vaccination 1, eligible participants received a single intramuscular dose of licensed QIV (vaccination 2).

Participants received a single injection of mIRV encoding A strain at dose level 3, intramuscularly into the deltoid muscle at Day 1. Following unblinding at 8 weeks after vaccination 1, eligible participants received a single intramuscular dose of licensed QIV (vaccination 2).

Participants received a single injection of mIRV encoding A strain at dose level 4, intramuscularly into the deltoid muscle at Day 1. Following unblinding at 8 weeks after vaccination 1, eligible participants received a single intramuscular dose of licensed QIV (vaccination 2).

Participants received a single injection of quadrivalent influenza vaccine (QIV), licensed, intramuscularly into the deltoid muscle at Day 1. Following unblinding at 8 weeks after vaccination 1, eligible participants received a single intramuscular dose of either mIRV A or B at dose level 4 (vaccination 2).

Participants received a single injection of mIRV encoding B strain at dose level 1, intramuscularly into the deltoid muscle at Day 1. Following unblinding at 8 weeks after vaccination 1, eligible participants received a single intramuscular dose of licensed QIV (vaccination 2).

Participants received a single injection of mIRV encoding B strain at dose level 2, intramuscularly into the deltoid muscle at Day 1. Following unblinding at 8 weeks after vaccination 1, eligible participants received a single intramuscular dose of licensed QIV (vaccination 2).

Participants received a single injection of mIRV encoding B strain at dose level 3, intramuscularly into the deltoid muscle at Day 1. Following unblinding at 8 weeks after vaccination 1, eligible participants received a single intramuscular dose of licensed QIV (vaccination 2).

Participants received a single injection of mIRV encoding B strain at dose level 4, intramuscularly into the deltoid muscle at Day 1. Following unblinding at 8 weeks after vaccination 1, eligible participants received a single intramuscular dose of licensed QIV (vaccination 2).

Participants received a single injection of QIV, licensed, intramuscularly into the deltoid muscle at Day 1. Following unblinding at 8 weeks after vaccination 1, eligible participants received a single intramuscular dose injection of mIRV encoding A strain or B strain at dose level 4 (vaccination 2).

Participants received a single injection of bivalent influenza modified RNA vaccine (bIRV) encoding A and B strains at dose level combination 1, intramuscularly into the deltoid muscle at Day 1. Following unblinding at 8 weeks after vaccination 1, eligible participants received a single intramuscular dose of licensed QIV (vaccination 2).

Participants received a single injection of bIRV encoding A and B strains at dose level combination 2, intramuscularly into the deltoid muscle at Day 1. Following unblinding at 8 weeks after vaccination 1, eligible participants received a single intramuscular dose of licensed QIV (vaccination 2).

Participants received a single injection of bIRV encoding A and B strains at dose level combination 3, intramuscularly into the deltoid muscle at Day 1. Following unblinding at 8 weeks after vaccination 1, eligible participants received a single intramuscular dose of licensed QIV (vaccination 2).

Participants received a single injection of bIRV encoding A and B strains at dose level combination 4, intramuscularly into the deltoid muscle at Day 1. Following unblinding at 8 weeks after vaccination 1, eligible participants received a single intramuscular dose of licensed QIV (vaccination 2).

Participants received a single injection of licensed quadrivalent influenza vaccine (QIV), intramuscularly into the deltoid muscle at Day 1. Following unblinding at 8 weeks after vaccination 1, eligible participants received a single intramuscular injection of mIRV encoding A strain or B strain at dose level 4 (vaccination 2).

Participants received a single injection of quadrivalent influenza mod RNA vaccine (qIRV) - encoding 2A strains and 2B strains at a dose level 1 per strain, intramuscularly into the deltoid muscle at Day 1. Following unblinding at 8 weeks after vaccination 1, eligible participants received a single intramuscular dose of licensed QIV (vaccination 2).

Participants received a single injection of licensed QIV, intramuscularly into the deltoid muscle at Day 1. Following unblinding at 8 weeks after vaccination 1, the licensed QIV control group received either a single intramuscular dose of injection of mIRV encoding A strain or B strain at dose level 4 (vaccination 2).

Participants aged 65 to 85 years received intramuscular injections with 2 doses qIRV at dose level 1 administered 21 days apart as a part of initial enrollment.

Participants aged 65 to 85 years received a single intramuscular injection of licensed QIV followed by a single intramuscular injection of bIRV encoding AA strains at dose level combination 1 administered 21 days apart as a part of initial enrollment.

Participants aged 65 to 85 years received a single intramuscular injection of licensed QIV followed by a single intramuscular injection of bIRV encoding AA strains at dose level combination 2 administered 21 days apart as a part of initial enrollment.

Participants aged 65 to 85 years received two doses of licensed QIV administered 21 days apart as a part of initial enrollment.

Participants aged 65 to 85 years received a single intramuscular injection of licensed QIV administered concurrently in the opposite arm with a single intramuscular injection of bIRV AA (dose level combination 1) as part of initial enrollment.

Participants aged 65 to 85 years received a single intramuscular injection of licensed QIV administered concurrently in the opposite arm with a single intramuscular injection of bIRV AA (dose level combination 2) as a part of initial enrollment.

Participants aged 65 to 85 years received a single intramuscular injection of qIRV dose level 2, encoding 2A strains and 2B strains (dose combination 1) as a part of initial enrollment.

Participants aged 65 to 85 years received a single intramuscular injection of qIRV dose level 2, dose combination 2 administered at day 1 as a part of initial enrollment.

Participants aged 65 to 85 years received a single intramuscular injection of bIRV AA + bIRV BB both dose level combination 1 administered at day 1 as a part of initial enrollment.

Participants aged 65 to 85 years received a single intramuscular injection of licensed QIV as part of initial enrollment.

Participants aged 65 to 85 years received a single intramuscular injection of qIRV dose level 3 administered at day 1 as a part of initial enrollment.

Participants aged 18 to 64 years received a single intramuscular injection of qIRV dose level 1 as a part of expanded enrollment.

Participants aged 18 to 64 years received a single intramuscular injection of qIRV dose level 2 as a part of expanded enrollment.

Participants aged 65 to 85 years received a single intramuscular injection of qIRV dose level 1 as a part of expanded enrollment

Participants aged 65 to 85 years received a single intramuscular injection of qIRV dose level 2, encoding 2A strains and 2B strains (dose combination 1) at Day 1 as part of expanded enrollment.

Participants aged 65 to 85 years received a single intramuscular injection of licensed QIV as a part of expanded enrollment.

Participants aged 65 to 85 years received intramuscular injections with 2 doses qIRV at dose Level 1 administered 21 days apart as a part of expanded enrollment.

Indicates participants randomized to either mIRV A, mIRV B, bIRV A, bIRV B or qIRV and received licensed QIV at vaccination 2. Also, includes participants who were randomized to 'Licensed QIV' and received either 'mIRV A or mIRV B at dose level 4' at vaccination 2.