An AE was any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An unsolicited AE was an observed AE that did not fulfill the conditions prelisted in the case report form (CRF) in terms of diagnosis and onset window post-vaccination. All participants were observed for 30 minutes after vaccination, and any unsolicited AEs that occurred during that time were recorded as immediate unsolicited AEs in the CRF. Reported AEs for each arm were presented as pre-specified in the study protocol.

Analysis was performed on SafAS which included all participants who had received the study vaccine(s) and were analyzed according to the vaccine they actually received and study intervention group.

A solicited reaction (SR) was an "expected" adverse reaction (sign or symptom) observed and reported under the conditions (nature and onset) pre-listed in the protocol and CRF. Solicited injection site reactions included injection site pain, axillary swelling and tenderness, injection site erythema, injection site swelling, injection site induration, and injection site bruising. Reported AEs for each arm were presented as pre-specified in the study protocol.

Analysis was performed on the SafAS. Here, 'overall number of participants analyzed' = participants with available data for this outcome measure.

A SR was an "expected" adverse reaction (sign or symptom) observed and reported under the conditions (nature and onset) prelisted (i.e., solicited) in the protocol and CRF. Solicited systemic reactions included fever, headache, malaise, myalgia, arthralgia, shivering, fatigue, nausea and vomiting. Reported AEs for each arm were presented as pre-specified in the study protocol.

Analysis was performed on the SafAS. Here, 'overall number of participants analyzed' = participants with available data for this outcome measure.

An AE was any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. An unsolicited AE was an observed AE that did not fulfill the conditions prelisted in the CRF in terms of diagnosis and/or onset window post-vaccination. Reported AEs for each arm were presented as pre-specified in the study protocol.

Analysis was performed on the SafAS.

An SAE was any untoward medical occurrence that at any dose 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, or was an important medical event. AESIs was defined as one of scientific and medical concern specific to the sponsor's study intervention or program, for which ongoing monitoring and rapid communication by the investigator to the sponsor was done. Reported AEs for each arm were presented as pre-specified in the study protocol.

Analysis was performed on the SafAS.

A MAAE was a new onset or a worsening of a condition that prompted the participant or participant's parent/legally acceptable representative to seek unplanned medical advice at a physician's office or emergency department including medical advice seeking during the study visit or routine medical care. Reported AEs for each arm were presented as pre-specified in the study protocol.

Analysis was performed on the SafAS population.

GMTs of anti-influenza and anti-COVID-19 antibodies were measured using hemagglutination inhibition (HAI) assay for 4 influenza virus strains: A/H1N1, A/H3N2, B/Yamagata, and B/Victoria. Titers were expressed in terms of 1/dilution.

Analysis was performed on Immunogenicity analysis set which included all randomized participants who received at least 1 dose of the study vaccine and analyzed according to the vaccine they actually received and study intervention group. Here, 'overall number of participants analyzed' = participants with available data for this outcome measure.

GMTs of anti-influenza and anti-COVID-19 antibodies were measured using HAI assay for 4 influenza virus strains: A/H1N1, A/H3N2, B/Yamagata, and B/Victoria. Titers were expressed in terms of 1/dilution.

Analysis was performed on Immunogenicity analysis set. Here, 'overall number of participants analyzed' = participants with available data for this outcome measure.

GMTs of anti-influenza and anti-COVID-19 antibodies were measured using HAI assay for 4 influenza virus strains: A/H1N1, A/H3N2, B/Victoria, and B/Yamagata. GMTRs were calculated as the ratio of GMTs post-vaccination (on Day 22) and pre-vaccination (on Day 1) i.e., Day 22/Day 01.

Analysis was performed on Immunogenicity analysis set. Here, 'overall number of participants analyzed' = participants with available data for this outcome measure.

Anti-influenza and anti-COVID 19 antibodies were measured using HAI assay method for 4 influenza virus strains: A/H1N1, A/H3N2, B/Victoria, and B/Yamagata. Percentage of participants with HAI titers >=10 (1/dilution) are reported in the outcome measure.

Analysis was performed on Immunogenicity analysis set. Here, 'overall number of participants analyzed' = participants with available data for this outcome measure.

Anti-influenza and anti-COVID 19 antibodies were measured using HAI assay method for 4 influenza virus strains: A/H1N1, A/H3N2, B/Victoria, and B/Yamagata. Percentage of participants with HAI titers >=10 (1/dilution) are reported in the outcome measure.

Analysis was performed on Immunogenicity analysis set. Here, 'overall number of participants analyzed' = participants with available data for this outcome measure.

Anti-influenza and anti-COVID-19 antibodies were measured by HAI assay for 4 influenza virus strains: A/H1N1, A/H3N2, B/Victoria, and B/Yamagata. Seroconversion was defined as either a pre-vaccination HAI titer less than (<)10 (1/dilution) and a post-vaccination titer >=40 (1/dilution) or a pre-vaccination titer >=10 (1/dilution) and a >= four-fold increase in post-vaccination titer at Day 22.

Analysis was performed on Immunogenicity analysis set. Here, 'overall number of participants analyzed' = participants with available data for this outcome measure.

Anti-influenza and anti-COVID 19 antibodies were measured using HAI assay method for 4 influenza virus strains: A/H1N1, A/H3N2, B/Victoria, and B/Yamagata. Percentage of participants with HAI titers >=40 (1/dilution) are reported in the outcome measure.

Analysis was performed on Immunogenicity analysis set. Here, 'overall number of participants analyzed' = participants with available data for this outcome measure.

Anti-influenza and anti-COVID 19 antibodies were measured using HAI assay method for 4 influenza virus strains: A/H1N1, A/H3N2, B/Victoria, and B/Yamagata. Percentage of participants with HAI titers >=40 (1/dilution) are reported in the outcome measure.

Analysis was performed on Immunogenicity analysis set. Here, 'overall number of participants analyzed' = participants with available data for this outcome measure.

GMCs of Anti-S binding IgG antibodies were assessed using enzyme-linked immunosorbent assay (ELISA) method and were measured in binding antibody units/milliliter (BAU/mL).

Analysis was performed on Immunogenicity analysis set. Here, 'overall number of participants analyzed' = participants with available data for this outcome measure.

GMCs of Anti-S binding IgG antibodies were assessed using ELISA method and were measured in BAU/mL.

Analysis was performed on Immunogenicity analysis set. Here, 'overall number of participants analyzed' = participants with available data for this outcome measure.

GMCs of Anti-S binding IgG antibodies were assessed using ELISA method. GMCR was calculated as the ratio of GMC post-vaccination (on Day 22) and pre-vaccination (on Day 1) i.e., Day 22/Day 01.

Analysis was performed on Immunogenicity analysis set. Here, 'overall number of participants analyzed' = participants with available data for this outcome measure.

Percentage of participants with >=2-fold and >=4-fold rise in Anti-S binding IgG antibodies at Day 22 (post-vaccination) are reported in this outcome measure. Percentage of participants with >=2-fold rise are those for whom the computed value at Day 22 was *2 compared to the computed value at Day 1 and percentage of participants with >=4-fold rise are those for whom the computed value at Day 22 was *4 compared to the computed value at Day 1.

Analysis was performed on immunogenicity analysis set. Here, 'overall number of participants analyzed' = participants with available data for this outcome measure.