Study to Evaluate the Safety, Tolerability, and Immunogenicity of an RNA Vaccine Candidate Against COVID-19 in Healthy Children

BioNTech SE11,837 enrolled

Overview

This is a Phase 1/2/3 study in healthy children. Dependent upon safety and/or immunogenicity data generated during the course of this study, and the resulting assessment of benefit-risk, the safety, tolerability, and immunogenicity of BNT162b2 in participants \<6 months of age may subsequently be evaluated.

Phase 1 Dose-Finding Is the open-label dose-finding portion of the study that will evaluate safety, tolerability, and immunogenicity of BNT162b2 administered on a 2-dose (separated by approximately 21 days) schedule in up to 3 age groups (participants ≥5 to \<12 years, ≥2 to \<5 years, and ≥6 months to \<2 years of age). Dose finding is being initiated in this study in participants ≥5 to \<12 years of age based on the acceptable blinded safety assessment of the 30-µg dose in 12- to 15-year-olds in the C4591001 study. The purpose of Phase 1 is to identify preferred dose level(s) of BNT162b2 from up to 3 different dose levels in each age group. Dependent upon safety and/or immunogenicity data generated during the course of this study, it is possible that dose levels may not be started, may be terminated early, and/or may be added with dose levels below the lowest stated dose. Update as part of protocol amendment 6: All participants will receive a third dose of BNT162b2. For participants ≥6 months to \<5 years, the third dose will occur at least 8 weeks after the second dose. In participants ≥5 to \<12 years, the third dose will occur at least 6 months after the second dose. The interval between the second and third doses will be based on the participant's age at the time of enrollment. The dose level of the third dose of BNT162b2 will be based on age at the time of vaccination: participants \<5 years of age at the time of the third dose will receive the 3-µg dose level, participants ≥5 to \<12 years of age at the time of the third dose will receive the 10-µg dose level, and participants ≥12 years of age at the time of the third dose will receive the 30-µg dose level. Participants will have blood drawn prior to both Dose 1 and Dose 2 and 7 days after Dose 2 to assess immunogenicity to determine the selected BNT162b2 dose level for Phase 2/3. Participants will also have blood drawn prior to Dose 3 and 1, 6, and 12 months after Dose 3. Phase 2/3 Selected-Dose Is the portion of the study that will evaluate the safety, tolerability, and immunogenicity in each age group at the selected dose level from the Phase 1 dose-finding portion of the study. Efficacy will be evaluated within or across age groups in which immunobridging is successful, depending on accrual of a sufficient number of cases in those age groups. Participants will have blood drawn at baseline prior to Dose 1 and 6 months after Dose 2. Immunobridging to participants 16 to 25 years of age in the C4591001 study will be based on immunogenicity data collected at (1) baseline and 1 month after Dose 2 and (2) baseline and 1 month after Dose 3. The persistence of the immune response will be based on immunogenicity data collected in participants at (1) baseline and 1 and 6 months after Dose 2 and (2) baseline and 1, 6, 12, and 18 months after Dose 3. In addition, efficacy against confirmed COVID-19 and against asymptomatic infection will also be assessed in participants ≥5 to \<12 years of age. At designated US sites, an additional optional whole blood sample of approximately 10 mL will be obtained prior to Dose 1 and at 7 days and 6 months after Dose 2 from up to approximately 60 participants ≥10 years of age. Additional samples will be obtained prior to Dose 3 and 1 month after Dose 3 (original BNT162b2 group only). These samples will be used on an exploratory basis to investigate the postvaccination cell-mediated immune response at these time points. At the 6-month follow-up visit, all participants will be unblinded. Participants who originally received placebo will be offered the opportunity to receive BNT162b2 as part of the study. Participants who originally received placebo and become eligible for receipt of BNT162b2 or another COVID-19 vaccine according to local or national recommendations prior to the 6 month follow-up visit (Visit 5 or 405) (detailed separately and available in the electronic study reference portal) will have the opportunity to receive BNT162b2 (10 µg or 3 µg) based on age at the time of vaccination. Update as part of protocol amendment 6: All participants will receive a third dose of BNT162b2. For participants ≥6 months to \<5 years, the third dose will occur at least 8 weeks after the second dose. In participants ≥5 to \<12 years, the third dose will occur at least 6 months after the second dose. The interval between the second and third doses will be based on the participant's age at the time of enrollment. The dose level of the second and third doses of BNT162b2 will be based on age at the time of vaccination: participants \<5 years of age at the time of the second/third dose will receive the 3-µg dose level, participants ≥5 to \<12 years of age at the time of the second/third dose will receive the 10-µg dose level, and participants ≥12 years of age at the time of the second/third dose will receive the 30-µg dose level. Phase 2/3 Obtaining Serum Samples for Potential Troponin I Testing If testing of troponin I levels in individuals who did not receive BNT162b2 indicates that troponin I level could be a reliable indicator of potential subclinical myocarditis, obtaining serum samples for potential troponin I testing during the period of increased risk of clinical myocarditis may help characterize the absence/presence and frequency of subclinical myocarditis. To assess, an additional group of participants will be included: ≥5 to \<12 years: randomized 2:1 to receive BNT162b2 10 µg or placebo, and ≥12 to \<16 years of age: open-label receipt of BNT162b2 30 µg. Update as part of protocol amendment 7: All participants will receive a third dose of BNT162b2. For all participants (≥5 to \<12 and ≥12 to \<16 years of age), the third dose will occur at least 5 months after Dose 2. The dose level of the second and third doses of BNT162b2 will be based on age at the time of vaccination: participants ≥5 to \<12 years of age at the time of the second/third dose will receive the 10-µg dose level, and participants ≥12 years of age at the time of the second/third dose will receive the 30-µg dose level. Update as part of protocol amendment 8: The Lower-Dose Evaluation portion of the protocol has been removed. Participation in the study will cease 6 months after the third dose of BNT162b2.

Study Type

INTERVENTIONAL

Allocation

NON_RANDOMIZED

Purpose

PREVENTION

Masking

NONE

Enrollment

11,837

Conditions

SARS-CoV-2 Infection, COVID-19

Interventions

Biological/Vaccine: BNT162b2 10mcgBIOLOGICAL

BNT162b2 Low/Mid-Dose (10mcg) level

BNT162b2 20mcgBIOLOGICAL

BNT162b2 Mid-Dose (20mcg) level

BNT162b2 30mcgBIOLOGICAL

BNT162b2 High-Dose (30mcg) level

Eligibility

Sex: ALLMin age: 6 MonthsMax age: 15 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria 1. Male or female participants ≥6 months to \<12 years of age, at the time of randomization, at Visit 1 for the dose-finding/selected-dose evaluation. For the obtaining-serum-samples-for-potential-troponin I-testing portion of the study: Male or female participants between ≥5 and \<16 years of age. 2. Participants' parent(s)/legal guardian(s) and participants, as age appropriate, who are willing and able to comply with all scheduled visits, treatment plan, laboratory tests, lifestyle considerations, and other study procedures. 3. Healthy participants who are determined by medical history, physical examination, and clinical judgment of the investigator to be eligible for inclusion in the study. Note: Healthy participants with preexisting stable disease, defined as disease not requiring significant change in the therapy or hospitalization for worsening disease during the 6 weeks before enrollment, can be included. 4. Participants are expected to be available for the duration of the study and whose parent(s)/legal guardian can be contacted by telephone during study participation. 5. Negative urine pregnancy test for female participants who are biologically capable of having children. 6. Female participant of childbearing potential or male participant able to father children who is willing to use a highly effective method of contraception as outlined in this protocol for at least 28 days after the last dose of study intervention if at risk of pregnancy with her/his partner; or female participant not of childbearing potential or male participant not able to father children. 7. The participant or participant's parent(s)/legal guardian is capable of giving signed informed consent, which includes compliance with the requirements and restrictions listed in the ICD and in this protocol. Depending on the age of the participant and according to local requirements, participants will also be asked to provide assent as appropriate (verbal or written). Exclusion Criteria 1. Phase 1 only: Past clinical (based on COVID-19 symptoms/signs alone, if a SARS CoV 2 NAAT result was not available) or microbiological (based on COVID-19 symptoms/signs and a positive SARS-CoV-2 NAAT result) diagnosis of COVID 19. 2. Phase 1 only: Known infection with HIV, HCV, or HBV. 3. Receipt of medications intended to prevent COVID-19. 4. Previous or current diagnosis of MIS-C. 5. Other medical or psychiatric condition including recent (within the past year) or active suicidal ideation/behavior or laboratory abnormality that may increase the risk of study participation or, in the investigator's judgment, make the participant inappropriate for the study. Note: This includes both conditions that may increase the risk associated with study intervention administration or a condition that may interfere with the interpretation of study results 6. History of severe adverse reaction associated with a vaccine and/or severe allergic reaction (eg, anaphylaxis) to any component of the study intervention(s). 7. Immunocompromised individuals with known or suspected immunodeficiency, as determined by history and/or laboratory/physical examination. 8. Individuals with a history of autoimmune disease or an active autoimmune disease requiring therapeutic intervention, including but not limited to systemic lupus erythematosus. Note: Stable type 1 diabetes and hypothyroidism are permitted. 9. Bleeding diathesis or condition associated with prolonged bleeding that would, in the opinion of the investigator, contraindicate intramuscular injection. 10. Female who is pregnant or breastfeeding. 11. Previous vaccination with any coronavirus vaccine. 12. Individuals who receive treatment with immunosuppressive therapy, including cytotoxic agents or systemic corticosteroids, eg, for cancer or an autoimmune disease, or planned receipt throughout the study. If systemic corticosteroids have been administered short term (\<14 days) for treatment of an acute illness, participants should not be enrolled into the study until corticosteroid therapy has been discontinued for at least 28 days before study intervention administration. Inhaled/nebulized, intra-articular, intrabursal, or topical (skin or eyes) corticosteroids are permitted. 13. Receipt of blood/plasma products, immunoglobulin, or monoclonal antibodies, from 60 days before study intervention administration, or receipt of any passive antibody therapy specific to COVID-19 from 90 days before study intervention administration, or planned receipt throughout the study. 14. Participation in other studies involving study intervention within 28 days prior to study entry and/or during study participation. 15. Previous participation in other studies involving study intervention containing LNPs. 16. Participants who are direct descendants (child or grandchild) of investigational site staff members or Pfizer/BioNTech employees directly involved in the conduct of the study, site staff otherwise supervised by the investigator, and their respective family members.

Locations (128)

Outcomes

Primary Outcomes

Phase 1: Percentage of Participants With Local Reactions Within 7 Days After Dose 1: >=5 to <12 Years of Age

Local reactions were collected in electronic diary (e-diary) or during unscheduled clinical assessments from Day 1 to 7 after Dose 1. Redness and swelling were measured and recorded in measuring device unit (mdu) where, 1 mdu = 0.5 centimeter (cm) and were graded as mild (\>=0.5 to 2.0 cm), moderate (\>2.0 to 7.0 cm), severe (\>7.0 cm) and Grade 4 (necrosis \[redness and swelling\] or exfoliative dermatitis \[redness\]). Pain at injection site was graded as mild (did not interfere with activity), moderate (interfered with activity), severe (prevented daily activity) and Grade 4 Emergency room (ER) visit or hospitalization). Grade 4 reactions were classified by investigator or medically qualified person. Reactions reported as adverse events in case report form within 7 days of study vaccination also included. Two-sided 95% confidence interval was based on Clopper and Pearson method.

Time frame: Phase 1: From Day 1 to Day 7 after Dose 1

Phase 1: Percentage of Participants With Local Reactions Within 7 Days After Dose 2: >=5 to <12 Years of Age

Local reactions were collected in e-diary or during unscheduled clinical assessments from Day 1 to Day 7 after Dose 2. Redness and swelling were measured and recorded in mdu where, 1 mdu =0.5 cm and were graded as mild (\>=0.5 to 2.0 cm), moderate (\>2.0 to 7.0 cm), severe (\>7.0 cm) and Grade 4 (necrosis \[redness and swelling\] or exfoliative dermatitis \[redness\]). Pain at injection site was graded as mild (did not interfere with activity), moderate (interfered with activity), severe (prevented daily activity) and Grade 4 ER visit or hospitalization. Grade 4 reactions were classified by investigator or medically qualified person. Reactions reported as adverse events in case report form within 7 days of study vaccination were also included. Two-sided 95% CI was based on Clopper and Pearson method.

Time frame: Phase 1: Day 1 to Day 7 after Dose 2

Phase 1: Percentage of Participants With Local Reactions Within 7 Days After Dose 3: >=5 to <12 Years of Age

Local reactions were collected in e-diary or during unscheduled clinical assessments from Day 1 to Day 7 after Dose 3. Redness and swelling were measured and recorded in mdu where, 1 mdu =0.5 cm and were graded as mild (\>=0.5 to 2.0 cm), moderate (\>2.0 to 7.0 cm), severe (\>7.0 cm) and Grade 4(necrosis \[redness and swelling\] or exfoliative dermatitis \[redness\]). Pain at injection site was graded as mild (did not interfere with activity), moderate (interfered with activity), severe (prevented daily activity) and Grade 4 ER visit or hospitalization. Grade 4 reactions were classified by investigator or medically qualified person. Reactions reported as adverse events in case report form within 7 days of study vaccination also included. Two-sided 95% CI was based on Clopper and Pearson method.

Data from ClinicalTrials.gov

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Intramuscular injection

Biological/Vaccine: BNT162b2 3mcgBIOLOGICAL

BNT162b2 Low-Dose (3mcg) level

University of Alabama at Birmingham - School of Medicine

Birmingham, Alabama, United States

Phoenix Children's Hospital

Phoenix, Arizona, United States

SCPMG/Kaiser Permanente Los Angeles Medical Center

Los Angeles, California, United States

Matrix Clinical Research

Los Angeles, California, United States

Madera Family Medical Group

Madera, California, United States

Kaiser Permanente Oakland

Oakland, California, United States

Clinical & Translational Research Unit (CTRU) & Spectrum BioBank, Stanford University

Palo Alto, California, United States

Lucile Packard Children's Hospital Stanford

Palo Alto, California, United States

Center for Clinical Trials, LLC

Paramount, California, United States

Center for Clinical Trials

Paramount, California, United States

...and 118 more locations

Time frame: Phase 1: Day 1 to Day 7 after Dose 3

Phase 1: Percentage of Participants With Systemic Events Within 7 Days After Dose 1: >=5 to <12 Years of Age

Systemic events were recorded in an e-diary and at unscheduled clinical assessments from Day 1 to Day 7 after Dose 1. Fever: oral temperature \>= 38.0 degree Celsius (deg C); categorized as \>=38.0 deg C, 38.0 to 38.4 deg C, \>38.4 to 38.9 deg C, \>38.9 to 40.0 deg C and \>40.0 deg C. Fatigue, headache, chills, new or worsened muscle pain \& new or worsened joint pain: mild (did not interfere with activity), moderate (some interference with activity), severe (prevented daily routine activity). Vomiting: mild:1-2 times in 24 hours, moderate: \>2 times in 24 hours; severe: required intravenous hydration. Diarrhea: mild: 2-3 loose stools in 24 hours, moderate: 4-5 loose stools in 24 hours, severe: 6 or more loose stools in 24 hours. Grade 4 for all events: except fever; ER visit/hospitalization and were classified by investigator or medically qualified person. Events reported as AEs in CRF within 7 days after vaccination were included. Exact 95% CI based on Clopper and Pearson method.

Time frame: Phase 1: Day 1 to Day 7 after Dose 1

Phase 1: Percentage of Participants With Systemic Events Within 7 Days After Dose 2: >=5 to <12 Years of Age

Systemic events were recorded in an e-diary and at unscheduled clinical assessments from Day 1 to Day 7 after Dose 2. Fever: oral temperature \>= 38.0 C; categorized as \>=38.0 deg C, 38.0 to 38.4 deg C, \>38.4 to 38.9 deg C, \>38.9 to 40.0 deg C and \>40.0 deg C. Fatigue, headache, chills, new or worsened muscle pain \& new or worsened joint pain: mild (did not interfere with activity), moderate (some interference with activity), severe (prevented daily routine activity). Vomiting: mild:1-2 times in 24 hours, moderate: \>2 times in 24 hours; severe: required intravenous hydration. Diarrhea: mild: 2-3 loose stools in 24 hours, moderate: 4-5 loose stools in 24 hours, severe: 6 or more loose stools in 24 hours. Grade 4 for all events: except fever; ER visit/hospitalization and were classified by investigator or medically qualified person. Events reported as AEs in CRF within 7 days after vaccination were included. Exact 95% CI based on Clopper and Pearson method.

Time frame: Phase 1: Day 1 to Day 7 after Dose 2

Phase 1: Percentage of Participants With Systemic Events Within 7 Days After Dose 3:>=5 to <12 Years of Age

Systemic events were recorded in an e-diary and at unscheduled clinical assessments from Day 1 to Day 7 after Dose 3. Fever: oral temperature \>= 38.0 C; categorized as \>=38.0 deg C, 38.0 to 38.4 deg C, \>38.4 to 38.9 deg C, \>38.9 to 40.0 deg C and \>40.0 deg C. Fatigue, headache, chills, new or worsened muscle pain \& new or worsened joint pain: mild (did not interfere with activity), moderate (some interference with activity), severe (prevented daily routine activity). Vomiting: mild:1-2 times in 24 hours, moderate: \>2 times in 24 hours; severe: required intravenous hydration. Diarrhea: mild: 2-3 loose stools in 24 hours, moderate: 4-5 loose stools in 24 hours, severe: 6 or more loose stools in 24 hours. Grade 4 for all events: except fever; ER visit/hospitalization and were classified by investigator or medically qualified person. Events reported as AEs in CRF within 7 days after vaccination were included. Exact 95% CI based on Clopper and Pearson method.

Time frame: Phase 1: Day 1 to Day 7 after Dose 3

Phase 1: Percentage of Participants With Local Reactions Within 7 Days After Dose 1: >=2 to <5 Years of Age

Local reactions were collected in e-diary or during unscheduled clinical assessments from Day 1 to Day 7 after Dose 1. Redness and swelling were measured and recorded in mdu where, 1 mdu =0.5 cm and were graded as mild (\>=0.5 to 2.0 cm), moderate (\>2.0 to 7.0 cm), severe (\>7.0 cm) and Grade 4 (necrosis \[redness and swelling\] or exfoliative dermatitis \[redness\]). Pain at injection site was graded as mild (did not interfere with activity), moderate (interfered with activity), severe (prevented daily activity) and Grade 4 ER visit or hospitalization. Grade 4 reactions were classified by investigator or medically qualified person. Reactions reported as adverse events in case report form within 7 days of study vaccination were also included. Two-sided 95% CI was based on Clopper and Pearson method.

Time frame: Phase 1: Day 1 to Day 7 after Dose 1

Phase 1: Percentage of Participants With Local Reactions Within 7 Days After Dose 2: >=2 to <5 Years of Age

Time frame: Phase 1: Day 1 to Day 7 after Dose 2

Phase 1: Percentage of Participants With Local Reactions Within 7 Days After Dose 3: >=2 to <5 Years of Age

Local reactions were collected in e-diary or during unscheduled clinical assessments from Day 1 to Day 7 after Dose 3. Redness and swelling were measured and recorded in mdu where, 1 mdu =0.5 cm and were graded as mild (\>=0.5 to 2.0 cm), moderate (\>2.0 to 7.0 cm), severe (\>7.0 cm) and Grade 4 (necrosis \[redness and swelling\] or exfoliative dermatitis \[redness\]). Pain at injection site was graded as mild (did not interfere with activity), moderate (interfered with activity), severe (prevented daily activity) and Grade 4 ER visit or hospitalization. Grade 4 reactions were classified by investigator or medically qualified person. Reactions reported as adverse events in case report form within 7 days of study vaccination were also included. Two-sided 95% CI was based on Clopper and Pearson method.

Time frame: Phase 1: Day 1 to Day 7 after Dose 3

Phase 1: Percentage of Participants With Systemic Events Within 7 Days After Dose 1: >=2 to <5 Years of Age

Systemic events were recorded in an e-diary and at unscheduled clinical assessments from Day 1 to Day 7 after Dose 1. Fever: oral temperature \>= 38.0 C; categorized as \>=38.0 deg C, 38.0 to 38.4 deg C, \>38.4 to 38.9 deg C, \>38.9 to 40.0 deg C and \>40.0 deg C. Fatigue, headache, chills, new or worsened muscle pain \& new or worsened joint pain: mild (did not interfere with activity), moderate (some interference with activity), severe (prevented daily routine activity). Vomiting: mild:1-2 times in 24 hours, moderate: \>2 times in 24 hours; severe: required intravenous hydration. Diarrhea: mild: 2-3 loose stools in 24 hours, moderate: 4-5 loose stools in 24 hours, severe: 6 or more loose stools in 24 hours. Grade 4 for all events: except fever; ER visit/hospitalization and were classified by investigator or medically qualified person. Events reported as AEs in CRF within 7 days after vaccination were included. Exact 95% CI based on Clopper and Pearson method.

Time frame: Phase 1: Day 1 to Day 7 after Dose 1

Phase 1: Percentage of Participants With Systemic Events Within 7 Days After Dose 2: >=2 to <5 Years of Age

Time frame: Phase 1: Day 1 to Day 7 after Dose 2

Phase 1: Percentage of Participants With Systemic Events Within 7 Days After Dose 3: >=2 to <5 Years of Age

Time frame: Phase 1: Day 1 to Day 7 after Dose 3

Phase 1: Percentage of Participants With Local Reactions Within 7 Days After Dose 1: >=6 Months to <2 Years of Age

Local reactions were collected in e-diary or during unscheduled clinical assessments from Day 1 to Day 7 after Dose 1. Redness and swelling were measured and recorded in mdu where, 1 mdu =0.5 cm and were graded as mild (\>=0.5 to 2.0 cm), moderate (\>2.0 to 7.0 cm), severe (\>7.0 cm) and Grade 4 (necrosis \[redness and swelling\] or exfoliative dermatitis \[redness\]). Tenderness at injection site was graded as mild (hurts if gently touched), moderate (hurts if gently touched with crying), severe (causes limitation of limb movement) and Grade 4 ER visit or hospitalization. Grade 4 reactions were classified by investigator or medically qualified person. Reactions reported as adverse events in case report form within 7 days of study vaccination were also included. Two-sided 95% CI was based on Clopper and Pearson method.

Time frame: Phase 1: Day 1 to Day 7 after Dose 1

Phase 1: Percentage of Participants With Local Reactions Within 7 Days After Dose 2: >=6 Months to <2 Years of Age

Local reactions were collected in e-diary or during unscheduled clinical assessments from Day 1 to Day 7 after Dose 2. Redness and swelling were measured and recorded in mdu where, 1 mdu =0.5 cm and were graded as mild (\>=0.5 to 2.0 cm), moderate (\>2.0 to 7.0 cm), severe (\>7.0 cm) and Grade 4 (necrosis \[redness and swelling\] or exfoliative dermatitis \[redness\]). Tenderness at injection site was graded as mild (hurts if gently touched), moderate (hurts if gently touched with crying), severe (causes limitation of limb movement) and Grade 4 ER visit or hospitalization. Grade 4 reactions were classified by investigator or medically qualified person. Reactions reported as adverse events in case report form within 7 days of study vaccination were also included. Two-sided 95% CI was based on Clopper and Pearson method.

Time frame: Phase 1: Day 1 to Day 7 after Dose 2

Phase 1: Percentage of Participants With Local Reactions Within 7 Days After Dose 3: >=6 Months to <2 Years of Age

Local reactions were collected in e-diary or during unscheduled clinical assessments from Day 1 to Day 7 after Dose 3. Redness and swelling were measured and recorded in mdu where, 1 mdu =0.5 cm and were graded as mild (\>=0.5 to 2.0 cm), moderate (\>2.0 to 7.0 cm), severe (\>7.0 cm) and Grade 4 (necrosis \[redness and swelling\] or exfoliative dermatitis \[redness\]). Tenderness at injection site was graded as mild (hurts if gently touched), moderate (hurts if gently touched with crying), severe (causes limitation of limb movement) and Grade 4 ER visit or hospitalization for severe tenderness at injection site). Grade 4 reactions were classified by investigator or medically qualified person. Reactions reported as adverse events in case report form within 7 days of study vaccination were also included. Two-sided 95% CI was based on Clopper and Pearson method.

Time frame: Phase 1: Day 1 to Day 7 after Dose 3

Phase 1: Percentage of Participants With Systemic Events Within 7 Days After Dose 1: >=6 Months to <2 Years of Age

Systemic events recorded in an e-diary and at unscheduled clinical assessments from Day 1 to 7 after Dose 1. Fever: oral temperature \>= 38.0 C; categorized as \>=38.0 deg C, 38.0 to 38.4 deg C, \>38.4 to 38.9 deg C, \>38.9 to 40.0 deg C and \>40.0 deg C. Decreased appetite: mild (decreased interest in eating), moderate (decreased oral intake), severe (refusal to feed). Drowsiness: mild (increased or prolonged sleeping bouts), moderate (slightly subdued interfering with daily activity), severe (disabling; not interested in usual daily activity). Irritability: mild (easily consolable), moderate (requiring increased attention), severe (Inconsolable; crying cannot be comforted). Grade 4 for all events except fever: ER visit/hospitalization and were classified by investigator or medically qualified person. Events reported as AEs in the CRF within 7 days after vaccination were also included. Exact 95% CI based on Clopper and Pearson method.

Time frame: Phase 1: Day 1 to Day 7 after Dose 1

Phase 1: Percentage of Participants With Systemic Events Within 7 Days After Dose 2: >=6 Months to <2 Years of Age

Systemic events recorded in an e-diary and at unscheduled clinical assessments from Day 1 to 7 after Dose 2.Fever: oral temperature \>= 38.0 C; categorized as \>=38.0 deg C, 38.0 to 38.4 deg C, \>38.4 to 38.9 deg C, \>38.9 to 40.0 deg C and \>40.0 deg C. Decreased appetite: mild (decreased interest in eating), moderate (decreased oral intake),severe (refusal to feed).Drowsiness: mild (increased or prolonged sleeping bouts), moderate (slightly subdued interfering with daily activity), severe (disabling; not interested in usual daily activity). Irritability: mild (easily consolable), moderate (requiring increased attention), severe (Inconsolable; crying cannot be comforted).Grade 4 for all events except fever: ER visit/hospitalization and were classified by investigator or medically qualified person. Events reported as AEs in the CRF within 7 days after vaccination were also included. Exact 95% CI based on Clopper and Pearson method.

Time frame: Phase 1: Day 1 to Day 7 after Dose 2

Phase 1: Percentage of Participants With Systemic Events Within 7 Days After Dose 3: >=6 Months to <2 Years of Age

Systemic events recorded in an e-diary and at unscheduled clinical assessments from Day 1 to 7 after Dose 3. Fever: oral temperature \>= 38.0 C; categorized as \>=38.0 deg C, 38.0 to 38.4 deg C, \>38.4 to 38.9 deg C, \>38.9 to 40.0 deg C and \>40.0 deg C. Decreased appetite: mild (decreased interest in eating), moderate (decreased oral intake), severe (refusal to feed). Drowsiness: mild (increased or prolonged sleeping bouts), moderate (slightly subdued interfering with daily activity), severe (disabling; not interested in usual daily activity).Irritability: mild (easily consolable), moderate (requiring increased attention), severe(Inconsolable; crying cannot be comforted).Grade 4 for all events except fever: ER visit/hospitalization and were classified by investigator or medically qualified person. Events reported as AEs in the CRF within 7 days after vaccination were also included. Exact 95% CI based on Clopper and Pearson method.

Time frame: Phase 1: Day 1 to Day 7 after Dose 3

Phase 1: Percentage of Participants Reporting Adverse Events (AEs) From Dose 1 to 1 Month After Dose 2: >=5 to <12 Years of Age

An AE was defined as 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. Percentage of participants reporting AEs from dose 1 to 1 month after dose 2 were reported in this outcome measure. Exact 2-sided 95% CI 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.

Time frame: Phase 1: From Dose 1 to 1 Month after Dose 2

Phase 1: Percentage of Participants Reporting Adverse Events From Dose 3 to 1 Month After Dose 3: >=5 to <12 Years of Age

An AE was defined as 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. Percentage of participants reporting AEs from dose 3 to 1 month after dose 3 were reported in this outcome measure. Only AEs collected by non-systematic assessment (i.e. excluding local reactions and systemic events) were reported in this outcome measure. Exact 2-sided 95% CI based on the Clopper and Pearson method.

Time frame: Phase 1: From Dose 3 to 1 Month after Dose 3

Phase 1: Percentage of Participants Reporting Serious Adverse Events (SAEs) From Dose 1 to 6 Months After Dose 2: >=5 to <12 Years of Age

A SAE was defined as any untoward medical occurrence that at any dose resulted in death, was life-threatening; resulted in persistent disability/incapacity; constituted a congenital anomaly/birth defect; was important medical event; required inpatient hospitalization or prolongation of existing hospitalization, was a suspected transmission via a Pfizer product of an infectious agent, pathogenic or non-pathogenic. Exact 2-sided 95% CI based on the Clopper and Pearson method.

Time frame: Phase 1: From Dose 1 to 6 Months after Dose 2

Phase 1: Percentage of Participants Reporting Serious Adverse Events From Dose 3 to 6 Months After Dose 3: >=5 to <12 Years of Age

An SAE was defined as any untoward medical occurrence that at any dose resulted in death, was life-threatening; resulted in persistent disability/incapacity; constituted a congenital anomaly/birth defect; was an important medical event; required inpatient hospitalization or prolongation of existing hospitalization, was a suspected transmission via a Pfizer product of an infectious agent, pathogenic or non-pathogenic Exact 2-sided 95% CI based on the Clopper and Pearson method.

Time frame: Phase 1: From Dose 3 to 6 Months after Dose 3

Phase 1: Percentage of Participants Reporting Adverse Events From Dose 1 to 1 Month After Dose 2: >=2 to <5 Years of Age

Time frame: Phase 1: From Dose 1 to 1 Month after Dose 2

Phase 1: Percentage of Participants Reporting Adverse Events From Dose 3 to 1 Month After Dose 3: >=2 to <5 Years of Age

An AE was defined as 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. Exact 2-sided 95% CI based on the Clopper and Pearson method. Percentage of participants reporting AEs from dose 3 to 1 month after dose 3 were reported in this outcome measure. Only AEs collected by non-systematic assessment (i.e. excluding local reactions and systemic events) were reported in this outcome measure.

Time frame: Phase 1: From Dose 3 to 1 Month after Dose 3

Phase 1: Percentage of Participants Reporting Serious Adverse Events From Dose 1 to 6 Months After Dose 2: >=2 to <5 Years of Age

An SAE was defined as any untoward medical occurrence that at any dose resulted in death, was life-threatening; resulted in persistent disability/incapacity; constituted a congenital anomaly/birth defect; was an important medical event; required inpatient hospitalization or prolongation of existing hospitalization, was a suspected transmission via a Pfizer product of an infectious agent, pathogenic or non-pathogenic. Exact 2-sided 95% CI based on the Clopper and Pearson method.

Time frame: Phase 1: From Dose 1 to 6 Months after Dose 2

Phase 1: Percentage of Participants Reporting Serious Adverse Events From Dose 3 to 6 Months After Dose 3: >=2 to <5 Years of Age

An SAE was defined as any untoward medical occurrence that at any dose resulted in death, was life-threatening; resulted in persistent disability/incapacity; constituted a congenital anomaly/birth defect; was an important medical event; required inpatient hospitalization or prolongation of existing hospitalization, was a suspected transmission via a Pfizer product of an infectious agent, pathogenic or non-pathogenic. Exact 2-sided 95% CI based on the Clopper and Pearson method.

Time frame: Phase 1: From Dose 3 to 6 Months after Dose 3

Phase 1: Percentage of Participants Reporting Adverse Events From Dose 1 to 1 Month After Dose 2: >=6 Months to <2 Years of Age

Time frame: Phase 1: From Dose 1 to 1 Month after Dose 2

Phase 1: Percentage of Participants Reporting Adverse Events From Dose 3 to 1 Month After Dose 3: >=6 Months to <2 Years of Age

An AE was defined as 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. Percentage of participants reporting AEs from dose 3 to 1 month after dose 3 were reported in this outcome measure. Exact 2-sided 95% CI 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.

Time frame: Phase 1: From Dose 3 to 1 Month after Dose 3

Phase 1: Percentage of Participants Reporting Serious Adverse Events From Dose 1 to 6 Months After Dose 2: >=6 Months to <2 Years of Age

An SAE was defined as any untoward medical occurrence that at any dose resulted in death, was life-threatening; resulted in persistent disability/incapacity; constituted a congenital anomaly/birth defect; was an important medical event; required inpatient hospitalization or prolongation of existing hospitalization, was a suspected transmission via a Pfizer product of an infectious agent, pathogenic or non-pathogenic.Exact 2-sided 95% CI based on the Clopper and Pearson method.

Time frame: Phase 1: From Dose 1 to 6 Months after Dose 2

Phase 1: Percentage of Participants Reporting Serious Adverse Events From Dose 3 to 6 Months After Dose 3: >=6 Months to <2 Years of Age

An SAE was defined as any untoward medical occurrence that at any dose resulted in death, was life-threatening; resulted in persistent disability/incapacity; constituted a congenital anomaly/birth defect; was an important medical event; required inpatient hospitalization or prolongation of existing hospitalization, was a suspected transmission via a Pfizer product of an infectious agent, pathogenic or non-pathogenic. Exact 2-sided 95% CI based on the Clopper and Pearson method.

Time frame: Phase 1: From Dose 3 to 6 Months after Dose 3

Phase 2/3: Percentage of Participants With Local Reactions Within 7 Days After Dose 1: Troponin Group: >=5 to <12 Years of Age

Local reactions were collected in e-diary or during unscheduled clinical assessments from Day 1 to Day 7 after Dose 1. Redness and swelling were measured and recorded in mdu where, 1 mdu =0.5 cm and were graded as mild \>2.0 to 5.0 cm), moderate (\>5.0 to 10.0), severe \>10.0 cm) and Grade 4 (necrosis \[redness and swelling\] or exfoliative dermatitis \[redness\]). Pain at injection site was graded as mild (did not interfere with activity), moderate (interfered with activity), severe (prevented daily activity) and Grade 4 ER visit or hospitalization for severe pain at injection site). Grade 4 reactions were classified by investigator or medically qualified person. Reactions reported as adverse events in case report form within 7 days of study vaccination also included. Two-sided 95% CI was based on Clopper and Pearson method.

Time frame: Phase 2/3: From Day 1 to Day 7 after Dose 1

Phase 2/3: Percentage of Participants With Local Reactions Within 7 Days After Dose 1: Troponin Group: >=12 to <16 Years of Age

Local reactions were collected in e-diary or during unscheduled clinical assessments from Day 1 to Day 7 after Dose 1. Redness and swelling were measured and recorded in mdu where, 1 mdu =0.5 cm and were graded as mild \>2.0 to 5.0 cm), moderate (\>5.0 to 10.0), severe \>10.0 cm) and Grade 4 (necrosis \[redness and swelling\] or exfoliative dermatitis \[redness\]). Pain at injection site was graded as mild (did not interfere with activity), moderate (interfered with activity), severe (prevented daily activity) and Grade 4 ER visit or hospitalization for severe pain at injection site). Grade 4 reactions were classified by investigator or medically qualified person. Reactions reported as adverse events in case report form within 7 days of study vaccination also included. Two-sided 95% CI was based on Clopper and Pearson method.

Time frame: Phase 2/3: From Day 1 to Day 7 after Dose 1

Phase 2/3: Percentage of Participants With Local Reactions Within 7 Days After Dose 2: Troponin Group: >=5 to <12 Years of Age

Local reactions were collected in e-diary or during unscheduled clinical assessments from Day 1 to Day 7 after Dose 2. Redness and swelling were measured and recorded in mdu where, 1 mdu =0.5 cm and were graded as mild (\>=0.5 to 2.0 cm), moderate (\>2.0 to 7.0 cm), severe (\>7.0 cm) and Grade 4 (necrosis \[redness and swelling\] or exfoliative dermatitis \[redness\]). Pain at injection site was graded as mild (did not interfere with activity), moderate (interfered with activity), severe (prevented daily activity) and Grade 4 ER visit or hospitalization for severe pain at injection site). Grade 4 reactions were classified by investigator or medically qualified person. Reactions reported as adverse events in case report form within 7 days of study vaccination also included. Two-sided 95% CI was based on Clopper and Pearson method.

Time frame: Phase 2/3: From Day 1 to Day 7 after Dose 2

Phase 2/3: Percentage of Participants With Local Reactions Within 7 Days After Dose 2: Troponin Group: >=12 to <16 Years of Age

Local reactions were collected in e-diary or during unscheduled clinical assessments from Day 1 to Day 7 after Dose 2. Redness and swelling were measured and recorded in mdu where, 1 mdu =0.5 cm and were graded as mild \>2.0 to 5.0 cm),moderate (\>5.0 to 10.0), severe \>10.0 cm) and Grade 4 (necrosis \[redness and swelling\] or exfoliative dermatitis \[redness\]). Pain at injection site was graded as mild (did not interfere with activity), moderate (interfered with activity), severe (prevented daily activity) and Grade 4 ER visit or hospitalization for severe pain at injection site). Grade 4 were classified by investigator or medically qualified person. Reactions reported as adverse events in case report form within 7 days of study vaccination also included. Two-sided 95% CI was based on Clopper and Pearson method.

Time frame: Phase 2/3: From Day 1 to Day 7 after Dose 2

Phase 2/3: Percentage of Participants With Local Reactions Within 7 Days After Dose 3: Troponin Group: >=5 to <12 Years of Age

Local reactions were collected in e-diary or during unscheduled clinical assessments from Day 1 to Day 7 after Dose 3. Redness and swelling were measured and recorded in mdu where, 1 mdu =0.5 cm and were graded as mild (\>=0.5 to 2.0 cm), moderate (\>2.0 to 7.0 cm), severe (\>7.0 cm) and Grade 4 (necrosis \[redness and swelling\] or exfoliative dermatitis \[redness\]). Pain at injection site was graded as mild (did not interfere with activity), moderate (interfered with activity), severe (prevented daily activity) and Grade 4 ER visit or hospitalization for severe pain at injection site). Grade 4 reactions were classified by investigator or medically qualified person. Reactions reported as adverse events in case report form within 7 days of study vaccination also included. Two-sided 95% CI was based on Clopper and Pearson method.

Time frame: Phase 2/3: From Day 1 to Day 7 after Dose 3

Phase 2/3: Percentage of Participants With Local Reactions Within 7 Days After Dose 3: Troponin Group: >=12 to <16 Years of Age

Local reactions were collected in e-diary or during unscheduled clinical assessments from Day 1 to Day 7 after Dose 3. Redness and swelling were measured and recorded in mdu where, 1 mdu =0.5 cm and were graded as mild \>2.0 to 5.0 cm), moderate (\>5.0 to 10.0), severe \>10.0 cm) and Grade 4 (necrosis \[redness and swelling\] or exfoliative dermatitis \[redness\]). Pain at injection site was graded as mild (did not interfere with activity), moderate (interfered with activity), severe (prevented daily activity) and Grade 4 ER visit or hospitalization for severe pain at injection site). Grade 4 were classified by investigator or medically qualified person. Reactions reported as adverse events in case report form within 7 days of study vaccination also included. Two-sided 95% CI was based on Clopper and Pearson method.

Time frame: Phase 2/3: From Day 1 to Day 7 after Dose 3

Phase 2/3: Percentage of Participants With Systemic Events Within 7 Days After Dose 1:Troponin Group: >=5 to <12 Years of Age

Systemic events were recorded in an e-diary and at unscheduled clinical assessments from up to Day 7 after Dose 1. Fever: oral temperature \>= 38.0 C; categorized as \>=38.0 deg C, 38.0 to 38.4 deg C, \>38.4 to 38.9 deg C, \>38.9 to 40.0 deg C and \>40.0 deg C. Fatigue, headache, chills, new or worsened muscle pain \& new or worsened joint pain: mild (did not interfere with activity), moderate (some interference with activity), severe (prevented daily routine activity). Vomiting: mild:1-2 times in 24 hours, moderate: \>2 times in 24 hours; severe: required intravenous hydration. Diarrhea: mild: 2-3 loose stools in 24 hours, moderate: 4-5 loose stools in 24 hours, severe: 6 or more loose stools in 24 hours. Grade 4 for all events: except fever; ER visit/hospitalization and were classified by investigator or medically qualified person. Events reported as AEs in CRF within 7 days after vaccination were included. Exact 95% CI based on Clopper and Pearson method.

Time frame: Phase 2/3: From Day 1 to Day 7 after Dose 1

Phase 2/3: Percentage of Participants With Systemic Events Within 7 Days After Dose 1: Troponin Group: >=12 to <16 Years of Age

Time frame: Phase 2/3: From Day 1 to Day 7 after Dose 1

Phase 2/3: Percentage of Participants With Systemic Events Within 7 Days After Dose 2: Troponin Group: >=5 to <12 Years of Age

Systemic events were recorded in an e-diary and at unscheduled clinical assessments from up to Day 7 after Dose 2. Fever: oral temperature \>= 38.0 C; categorized as \>=38.0 deg C, 38.0 to 38.4 deg C, \>38.4 to 38.9 deg C, \>38.9 to 40.0 deg C and \>40.0 deg C. Fatigue, headache, chills, new or worsened muscle pain \& new or worsened joint pain: mild (did not interfere with activity), moderate (some interference with activity), severe (prevented daily routine activity). Vomiting: mild:1-2 times in 24 hours, moderate: \>2 times in 24 hours; severe: required intravenous hydration. Diarrhea: mild: 2-3 loose stools in 24 hours, moderate: 4-5 loose stools in 24 hours, severe: 6 or more loose stools in 24 hours. Grade 4 for all events: except fever; ER visit/hospitalization and were classified by investigator or medically qualified person. Events reported as AEs in CRF within 7 days after vaccination were included. Exact 95% CI based on Clopper and Pearson method.

Time frame: Phase 2/3: From Day 1 to Day 7 after Dose 2

Phase 2/3: Percentage of Participants With Systemic Events Within 7 Days After Dose 2: Troponin Group: >=12 to <16 Years of Age

Time frame: Phase 2/3: From Day 1 to Day 7 after Dose 2

Phase 2/3: Percentage of Participants With Systemic Events Within 7 Days After Dose 3: Troponin Group: >=5 to <12 Years of Age

Systemic events were recorded in an e-diary and at unscheduled clinical assessments from up to Day 7 after Dose 3. Fever: oral temperature \>= 38.0 C; categorized as \>=38.0 deg C, 38.0 to 38.4 deg C, \>38.4 to 38.9 deg C, \>38.9 to 40.0 deg C and \>40.0 deg C. Fatigue, headache, chills, new or worsened muscle pain \& new or worsened joint pain: mild (did not interfere with activity), moderate (some interference with activity), severe (prevented daily routine activity). Vomiting: mild:1-2 times in 24 hours, moderate: \>2 times in 24 hours; severe: required intravenous hydration. Diarrhea: mild: 2-3 loose stools in 24 hours, moderate: 4-5 loose stools in 24 hours, severe: 6 or more loose stools in 24 hours. Grade 4 for all events: except fever; ER visit/hospitalization and were classified by investigator or medically qualified person. Events reported as AEs in CRF within 7 days after vaccination were included. Exact 95% CI based on Clopper and Pearson method.

Time frame: Phase 2/3: From Day 1 to Day 7 after Dose 3

Phase 2/3: Percentage of Participants With Systemic Events Within 7 Days After Dose 3: Troponin Group: >=12 to <16 Years of Age

Time frame: Phase 2/3: From Day 1 to Day 7 after Dose 3

Phase 2/3: Percentage of Participants Reporting Adverse Events From Dose 1 to 1 Month After Dose 2: Troponin Group: >=5 to <12 Years of Age

An AE was defined as 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. Percentage of participants reporting AEs from dose 1 to 1 month after dose 2 were reported in this outcome measure. Exact 2-sided CI 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.

Time frame: Phase 2/3: From Dose 1 to 1 Month after Dose 2

Phase 2/3: Percentage of Participants Reporting Adverse Events From Dose 1 to 1 Month After Dose 2: Troponin Group: >=12 to <16 Years of Age

An AE was defined as 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. Percentage of participants reporting AEs from dose 1 to 1 month after dose 2 were reported in this outcome measure. Exact 2-sided CI 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.

Time frame: Phase 2/3: From Dose 1 to 1 Month after Dose 2

Phase 2/3: Percentage of Participants Reporting Adverse Events From Dose 3 to 1 Month After Dose 3: Troponin Group: >=5 to <12 Years of Age

An AE was defined as 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. Percentage of participants reporting AEs from dose 3 to 1 month after dose 3 were reported in this outcome measure. Exact 2-sided CI 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.

Time frame: Phase 2/3: From Dose 3 to 1 Month after Dose 3

Phase 2/3: Percentage of Participants Reporting Adverse Events From Dose 3 to 1 Month After Dose 3: Troponin Group:>=12 to <16 Years of Age

An AE was defined as 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. Percentage of participants reporting AEs after dose 3 to 1 month from dose 3 were reported in this outcome measure. Exact 2-sided CI 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.

Time frame: Phase 2/3: From Dose 3 to 1 Month after Dose 3

Phase 2/3: Percentage of Participants Reporting Serious Adverse Events From Dose 1 to 6 Months After Dose 2 : Troponin Group: >=5 to <12 Years of Age

An SAE was defined as any untoward medical occurrence that at any dose resulted in death, was life-threatening; resulted in persistent disability/incapacity; constituted a congenital anomaly/birth defect; was an important medical event; required inpatient hospitalization or prolongation of existing hospitalization, was a suspected transmission via a Pfizer product of an infectious agent, pathogenic or non-pathogenic. Exact 2-sided 95% CI was based on the Clopper and Pearson method.

Time frame: Phase 2/3: From Dose 1 to 6 Months after Dose 2

Phase 2/3: Percentage of Participants Reporting Serious Adverse Events From Dose 1 to 6 Months After Dose 2: Troponin Group: >=12 to <16 Years of Age

An SAE was defined as any untoward medical occurrence that at any dose resulted in death, was life-threatening; resulted in persistent disability/incapacity; constituted a congenital anomaly/birth defect; was an important medical event; required inpatient hospitalization or prolongation of existing hospitalization, was a suspected transmission via a Pfizer product of an infectious agent, pathogenic or non-pathogenic. Exact 2-sided 95% CI was based on the Clopper and Pearson method.

Time frame: Phase 2/3: From Dose 1 to 6 Months after Dose 2

Phase 2/3: Percentage of Participants Reporting Serious Adverse Events From Dose 3 to 6 Months After Dose 3: Troponin Group: >=5 to <12 Years of Age

An SAE was defined as any untoward medical occurrence that at any dose resulted in death, was life-threatening; resulted in persistent disability/incapacity; constituted a congenital anomaly/birth defect; was important medical event; required inpatient hospitalization or prolongation of existing hospitalization, was a suspected transmission via a Pfizer product of an infectious agent, pathogenic or non-pathogenic. Exact 2-sided 95% CI was based on the Clopper and Pearson method.

Time frame: Phase 2/3: From Dose 3 to 6 Months after Dose 3

Phase 2/3: Percentage of Participants Reporting Serious Adverse Events From Dose 3 to 6 Months After Dose 3 : Troponin Group:>=12 to <16 Years of Age

An SAE was defined as any untoward medical occurrence that at any dose resulted in death, was life-threatening; resulted in persistent disability/incapacity; constituted a congenital anomaly/birth defect; was important medical event; required inpatient hospitalization or prolongation of existing hospitalization, was a suspected transmission via a Pfizer product of an infectious agent, pathogenic or non-pathogenic. Exact 2-sided 95% CI was based on the Clopper and Pearson method.

Time frame: Phase 2/3: From Dose 3 to 6 Months after Dose 3

Phase 2/3: Percentage of Participants With Local Reactions Within 7 Days After Dose 1: >=5 to <12 Years of Age

Local reactions were collected in e-diary or during unscheduled clinical assessments from Day 1 to Day 7 after Dose 1. Redness and swelling were measured and recorded in mdu where, 1 mdu =0.5 cm and were graded as mild (\>=0.5 to 2.0 cm), moderate (\>2.0 to 7.0 cm), severe (\>7.0 cm) and Grade 4 (necrosis \[redness and swelling\] or exfoliative dermatitis \[redness\]). Pain at injection site was graded as mild (did not interfere with activity), moderate (interfered with activity), severe (prevented daily activity) and Grade 4 ER visit or hospitalization for severe pain at injection site). Grade 4 reactions were classified by investigator or medically qualified person. Reactions reported as adverse events in case report form within 7 days of study vaccination also included. Two-sided 95% CI was based on Clopper and Pearson method.

Time frame: Phase 2/3: From Day 1 to Day 7 after Dose 1

Phase 2/3: Percentage of Participants With Local Reactions Within 7 Days After Dose 2: >=5 to <12 Years of Age

Local reactions were collected in e-diary or during unscheduled clinical assessments from Day 1 to Day 7 after Dose 2. Redness and swelling were measured and recorded in mdu where, 1 mdu =0.5 cm and were graded as mild (\>=0.5 to 2.0 cm), moderate (\>2.0 to 7.0 cm), severe (\>7.0 cm) and Grade 4 (necrosis \[redness and swelling\] or exfoliative dermatitis \[redness\]). Pain at injection site was graded as mild (did not interfere with activity),moderate (interfered with activity),severe (prevented daily activity) and Grade 4 ER visit or hospitalization for severe pain at injection site). Grade 4 reactions were classified by investigator or medically qualified person. Reactions reported as adverse events in case report form within 7 days of study vaccination also included. Two-sided 95% CI was based on Clopper and Pearson method.

Time frame: Phase 2/3: From Day 1 to Day 7 after Dose 2

Phase 2/3: Percentage of Participants With Local Reactions Within 7 Days After Dose 3: >=5 to <12 Years of Age

Local reactions were collected in e-diary or during unscheduled clinical assessments from Day 1 to Day 7 after Dose 3. Redness and swelling were measured and recorded in mdu where, 1 mdu =0.5 cm and were graded as mild(\>=0.5 to 2.0 cm),moderate (\>2.0 to 7.0 cm),severe (\>7.0 cm) and Grade 4 (necrosis \[redness and swelling\] or exfoliative dermatitis \[redness\]). Pain at injection site was graded as mild (did not interfere with activity),moderate (interfered with activity), severe (prevented daily activity) and Grade 4 ER visit or hospitalization for severe pain at injection site).Grade 4 were classified by investigator or medically qualified person. Reactions reported as adverse events in case report form within 7 days of study vaccination also included. Two-sided 95% CI was based on Clopper and Pearson method.

Time frame: Phase 2/3: From Day 1 to Day 7 after Dose 3

Phase 2/3: Percentage of Participants With Systemic Events Within 7 Days After Dose 1: >=5 to <12 Years of Age

Systemic events were recorded in an e-diary and at unscheduled clinical assessments up to Day 7 after Dose 1. Fever: oral temperature \>= 38.0 C; categorized as \>=38.0 deg C, 38.0 to 38.4 deg C, \>38.4 to 38.9 deg C, \>38.9 to 40.0 deg C and \>40.0 deg C. Fatigue, headache, chills, new or worsened muscle pain \& new or worsened joint pain: mild (did not interfere with activity), moderate (some interference with activity), severe(prevented daily routine activity). Vomiting: mild:1-2 times in 24 hours, moderate: \>2 times in 24 hours; severe: required intravenous hydration. Diarrhea: mild: 2-3 loose stools in 24 hours, moderate: 4-5 loose stools in 24 hours, severe: 6 or more loose stools in 24 hours. Grade 4 for all events: except fever; ER visit/hospitalization and were classified by investigator or medically qualified person. Events reported as AEs in CRF within 7 days after vaccination were included. Exact 95% CI based on Clopper and Pearson method.

Time frame: Phase 2/3: From Day 1 to Day 7 after Dose 1

Phase 2/3: Percentage of Participants With Systemic Events Within 7 Days After Dose 2: >=5 to <12 Years of Age

Systemic events were recorded in an e-diary and at unscheduled clinical assessments up to Day 7 after Dose 2. Fever: 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 and \>40.0 deg C. Fatigue, headache, chills, new or worsened muscle pain \& new or worsened joint pain: mild (did not interfere with activity), moderate (some interference with activity), severe (prevented daily routine activity). Vomiting: mild:1-2 times in 24 hours, moderate: \>2 times in 24 hours; severe: required intravenous hydration. Diarrhea: mild: 2-3 loose stools in 24 hours, moderate: 4-5 loose stools in 24 hours, severe: 6 or more loose stools in 24 hours. Grade 4 for all events: except fever; ER visit/hospitalization and were classified by investigator or medically qualified person. Events reported as AEs in CRF within 7 days after vaccination were included. Exact 95% CI based on Clopper and Pearson method.

Time frame: Phase 2/3: From Day 1 to Day 7 after Dose 2

Phase 2/3: Percentage of Participants With Systemic Events Within 7 Days After Dose 3: >=5 to <12 Years of Age

Systemic events were recorded in an e-diary and at unscheduled clinical assessments up to Day 7 after Dose 3. Fever: 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 and \>40.0 deg C. Fatigue, headache, chills, new or worsened muscle pain \& new or worsened joint pain: mild (did not interfere with activity), moderate (some interference with activity), severe (prevented daily routine activity). Vomiting: mild:1-2 times in 24 hours, moderate: \>2 times in 24 hours; severe: required intravenous hydration. Diarrhea: mild: 2-3 loose stools in 24 hours, moderate: 4-5 loose stools in 24 hours, severe: 6 or more loose stools in 24 hours. Grade 4 for all events: except fever; ER visit/hospitalization and were classified by investigator or medically qualified person. Events reported as AEs in CRF within 7 days after vaccination were included. Exact 95% CI based on Clopper and Pearson method.

Time frame: Phase 2/3: From Day 1 to Day 7 after Dose 3

Phase 2/3: Percentage of Participants With Local Reactions Within 7 Days After Dose 1: >=2 to <5 Years of Age

Local reactions were collected in e-diary or during unscheduled clinical assessments from Day 1 to Day 7 after Dose 1.Redness and swelling were measured and recorded in mdu where, 1 mdu =0.5 cm and were graded as mild (\>=0.5 to 2.0 cm), moderate (\>2.0 to 7.0 cm), severe (\>7.0 cm) and Grade 4 (necrosis\[redness and swelling\] or exfoliative dermatitis \[redness\]). Pain at injection site was graded as mild (did not interfere with activity), moderate (interfered with activity),severe (prevented daily activity) and Grade 4 ER visit or hospitalization. Grade 4 reactions were classified by investigator or medically qualified person. Reactions reported as adverse events in case report form within 7 days of study vaccination also included. Two-sided 95% CI was based on Clopper and Pearson method.

Time frame: Phase 2/3: From Day 1 to Day 7 after Dose 1

Phase 2/3: Percentage of Participants With Local Reactions Within 7 Days After Dose 2: >=2 to <5 Years of Age

Local reactions were collected in e-diary or during unscheduled clinical assessments from Day 1 to Day 7 after Dose 2. Redness and swelling were measured and recorded in mdu where, 1 mdu =0.5 cm and were graded as mild (\>=0.5 to 2.0 cm), moderate (\>2.0 to 7.0 cm), severe (\>7.0 cm) and Grade 4 (necrosis \[redness and swelling\] or exfoliative dermatitis \[redness\]). Pain at injection site was graded as mild (did not interfere with activity), moderate (interfered with activity), severe (prevented daily activity) and Grade 4 ER visit or hospitalization. Grade 4 reactions were classified by investigator or medically qualified person. Reactions reported as adverse events in case report form within 7 days of study vaccination also included. Two-sided 95% CI was based on Clopper and Pearson method.

Time frame: Phase 2/3: From Day 1 to Day 7 after Dose 2

Phase 2/3: Percentage of Participants With Local Reactions Within 7 Days After Dose 3: >=2 to <5 Years of Age

Local reactions were collected in e-diary or during unscheduled clinical assessments from Day 1 to Day 7 after Dose 3. Redness and swelling were measured and recorded in mdu where, 1 mdu =0.5 cm and were graded as mild (\>=0.5 to 2.0 cm), moderate (\>2.0 to 7.0 cm), severe (\>7.0 cm) and Grade 4 (necrosis \[redness and swelling\] or exfoliative dermatitis \[redness\]). Pain at injection site was graded as mild (did not interfere with activity), moderate (interfered with activity), severe (prevented daily activity) and Grade 4 ER visit or hospitalization. Grade 4 reactions were classified by investigator or medically qualified person. Reactions reported as adverse events in case report form within 7 days of study vaccination also included. Two-sided 95% CI was based on Clopper and Pearson method

Time frame: Phase 2/3: From Day 1 to Day 7 after Dose 3

Phase 2/3: Percentage of Participants With Systemic Events Within 7 Days After Dose 1: >=2 to <5 Years of Age

Systemic events were recorded in an e-diary and at unscheduled clinical assessments from Day 1 to Day 7 after Dose 1. Fever: 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 and \>40.0 deg C. Fatigue, headache, chills, new or worsened muscle pain \& new or worsened joint pain: mild (did not interfere with activity), moderate (some interference with activity), severe (prevented daily routine activity). Vomiting: mild:1-2 times in 24 hours, moderate: \>2 times in 24 hours; severe: required intravenous hydration. Diarrhea: mild: 2-3 loose stools in 24 hours, moderate: 4-5 loose stools in 24 hours, severe: 6 or more loose stools in 24 hours. Grade 4 for all events: except fever; ER visit/hospitalization and were classified by investigator or medically qualified person. Events reported as AEs in CRF within 7 days after vaccination were included. Exact 95% CI based on Clopper and Pearson method.

Time frame: Phase 2/3: From Day 1 to Day 7 after Dose 1

Phase 2/3: Percentage of Participants With Systemic Events Within 7 Days After Dose 2: >=2 to <5 Years of Age

Time frame: Phase 2/3: From Day 1 to Day 7 after Dose 2

Phase 2/3: Percentage of Participants With Systemic Events Within 7 Days After Dose 3: >=2 to <5 Years of Age

Time frame: Phase 2/3: From Day 1 to Day 7 after Dose 3

Phase 2/3: Percentage of Participants With Local Reactions Within 7 Days After Dose 1: >=6 Months to <2 Years of Age

Local reactions were collected in e-diary or during unscheduled clinical assessments from Day 1 to Day 7 after Dose 1. Redness and swelling were measured and recorded in mdu where,1 mdu =0.5 cm and were graded as mild (\>=0.5 to 2.0 cm), moderate (\>2.0 to 7.0 cm), severe (\>7.0 cm) and Grade 4 (necrosis \[redness and swelling\] or exfoliative dermatitis \[redness\]). Tenderness at injection site was graded as mild (hurts if gently touched), moderate (hurts if gently touched with crying), severe (causes limitation of limb movement) and Grade 4 (ER visit or hospitalization).Grade 4 were classified by investigator or medically qualified person. Reactions reported as adverse events in case report form within 7 days of study vaccination were also included. Two-sided 95% CI was based on Clopper and Pearson method.

Time frame: Phase 2/3: From Day 1 to Day 7 after Dose 1

Phase 2/3: Percentage of Participants With Local Reactions Within 7 Days After Dose 2: >=6 Months to <2 Years of Age

Local reactions were collected in e-diary or during unscheduled clinical assessments from Day 1 to Day 7 after Dose 2. Redness and swelling were measured and recorded in mdu where,1 mdu =0.5 cm and were graded as mild (\>=0.5 to 2.0 cm), moderate (\>2.0 to 7.0 cm), severe (\>7.0 cm) and Grade 4 (necrosis \[redness and swelling\] or exfoliative dermatitis \[redness\]). Tenderness at injection site was graded as mild (hurts if gently touched), moderate(hurts if gently touched with crying), severe (causes limitation of limb movement) and Grade 4 (ER visit or hospitalization).Grade 4 were classified by investigator or medically qualified person. Reactions reported as adverse events in case report form within 7 days of study vaccination were also included. Two-sided 95% CI was based on Clopper and Pearson method.

Time frame: Phase 2/3: From Day 1 to Day 7 after Dose 2

Phase 2/3: Percentage of Participants With Local Reactions Within 7 Days After Dose 3: >=6 Months to <2 Years of Age

Local reactions were collected in e-diary or during unscheduled clinical assessments from Day 1 to Day 7 after Dose 3. Redness and swelling were measured and recorded in mdu where,1 mdu =0.5 cm and were graded as mild (\>=0.5 to 2.0 cm), moderate (\>2.0 to 7.0 cm), severe (\>7.0 cm) and Grade 4 (necrosis \[redness and swelling\] or exfoliative dermatitis \[redness\]). Tenderness at injection site was graded as mild (hurts if gently touched), moderate (hurts if gently touched with crying), severe (causes limitation of limb movement) and Grade 4 (ER visit or hospitalization).Grade 4 were classified by investigator or medically qualified person. Reactions reported as adverse events in case report form within 7 days of study vaccination were also included. Two-sided 95% CI was based on Clopper and Pearson method.

Time frame: Phase 2/3: From Day 1 to Day 7 after Dose 3

Phase 2/3: Percentage of Participants With Systemic Events Within 7 Days After Dose 1: >=6 Months to <2 Years of Age

Systemic events recorded in an e-diary \& at unscheduled clinical assessments up to Day 7 after Dose 1. Fever: oral temperature \>= 38.0 deg C; categorised as \>=38.0 to 38.4 deg C,\>38.4 to 38.9 deg C, \>38.9 to 40.0 deg C and \>40.0 deg C. Decreased appetite: mild (decreased interest in eating),moderate (decreased oral intake),severe(refusal to feed). Drowsiness: mild (increased or prolonged sleeping bouts), moderate (slightly subdued interfering with daily activity), severe (disabling; not interested in usual daily activity). Irritability: mild (easily consolable), moderate (requiring increased attention), severe (Inconsolable; crying cannot be comforted). Grade 4 for all events: ER visit or hospitalization and were classified by investigator or medically qualified person. Events reported as AEs in CRF within 7 days after vaccination were also included. Exact 95% CI based on Clopper and Pearson method.

Time frame: Phase 2/3: From Day 1 to Day 7 after Dose 1

Phase 2/3: Percentage of Participants With Systemic Events Within 7 Days After Dose 2: >=6 Months to <2 Years of Age

Systemic events recorded in an e-diary \& at unscheduled clinical assessments up to Day 7 after Dose 2. Fever: oral temperature \>= 38.0 deg C; categorised as \>=38.0 to 38.4 deg C,\>38.4 to 38.9 deg C, \>38.9 to 40.0 deg C and \>40.0 deg C. Decreased appetite: mild (decreased interest in eating), moderate (decreased oral intake), severe (refusal to feed). Drowsiness: mild (increased or prolonged sleeping bouts), moderate (slightly subdued interfering with daily activity), severe (disabling; not interested in usual daily activity). Irritability: mild (easily consolable), moderate (requiring increased attention), severe (Inconsolable; crying cannot be comforted). Grade 4 for all events: ER visit or hospitalization and were classified by investigator or medically qualified person. Events reported as AEs in CRF within 7 days after vaccination were also included. Exact 95% CI based on Clopper and Pearson method.

Time frame: Phase 2/3: From Day 1 to Day 7 after Dose 2

Phase 2/3: Percentage of Participants With Systemic Events Within 7 Days After Dose 3: >=6 Months to <2 Years of Age

Systemic events recorded in an e-diary and at unscheduled clinical assessments up to Day 7 after Dose 3. Fever: oral temperature \>= 38.0 deg C; categorised as \>=38.0 to 38.4 deg C,\>38.4 to 38.9 deg C, \>38.9 to 40.0 deg C and \>40.0 deg C. Decreased appetite: mild (decreased interest in eating), moderate (decreased oral intake), severe (refusal to feed). Drowsiness: mild (increased or prolonged sleeping bouts), moderate (slightly subdued interfering with daily activity), severe(disabling; not interested in usual daily activity). Irritability: mild (easily consolable), moderate (requiring increased attention), severe (Inconsolable; crying cannot be comforted). Grade 4 for all events: ER visit or hospitalization and were classified by investigator or medically qualified person. Events reported as AEs in CRF within 7 days after vaccination were also included. Exact 95% CI based on Clopper and Pearson method.

Time frame: Phase 2/3: From Day 1 to Day 7 after Dose 3

Phase 2/3: Percentage of Participants Reporting Adverse Events From Dose 1 to 1 Month After Dose 2: >=5 to <12 Years of Age

An AE was defined as 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. Percentage of participants reporting AEs from dose 1 to 1 month after dose 2 were reported in this outcome measure. Exact 2-sided CI 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.

Time frame: Phase 2/3: From Dose 1 to 1 Month after Dose 2

Phase 2/3: Percentage of Participants Reporting Adverse Events From Dose 3 to 1 Month After Dose 3: >=5 to <12 Years of Age

An AE was defined as 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. Percentage of participants reporting AEs from dose 3 to 1 month after dose 3 were reported in this outcome measure. Exact 2-sided CI 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.

Time frame: Phase 2/3: From Dose 3 to 1 Month after Dose 3

Phase 2/3: Percentage of Participants Reporting Serious Adverse Events From Dose 1 to 6 Months After Dose 2 : >=5 to <12 Years of Age

An SAE was defined as any untoward medical occurrence that at any dose resulted in death, was life-threatening; resulted in persistent disability/incapacity; constituted a congenital anomaly/birth defect; was an important medical event; required inpatient hospitalization or prolongation of existing hospitalization, was a suspected transmission via a Pfizer product of an infectious agent, pathogenic or non-pathogenic. Exact 2-sided 95% CI was based on the Clopper and Pearson method.

Time frame: Phase 2/3: From Dose 1 to 6 Months after Dose 2

Phase 2/3: Percentage of Participants Reporting Serious Adverse Events From Dose 3 to 6 Months After Dose 3: >=5 to <12 Years of Age

An SAE was defined as any untoward medical occurrence that at any dose resulted in death, was life-threatening; resulted in persistent disability/incapacity; constituted a congenital anomaly/birth defect; was an important medical event; required inpatient hospitalization or prolongation of existing hospitalization, was a suspected transmission via a Pfizer product of an infectious agent, pathogenic or non-pathogenic. Exact 2-sided 95% CI was based on the Clopper and Pearson method.

Time frame: Phase 2/3: From Dose 3 to 6 Months after Dose 3

Phase 2/3: Percentage of Participants Reporting Adverse Events From Dose 1 to 1 Month After Dose 2: >=2 to <5 Years of Age

An AE was defined as 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. Percentage of participants reporting AEs after dose 1 to 1 month from dose 2 were reported in this outcome measure. Exact 2-sided CI 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.

Time frame: Phase 2/3: From Dose 1 to 1 Month after Dose 2

Phase 2/3: Percentage of Participants Reporting Adverse Events From Dose 3 to 1 Month After Dose 3:>=2 to <5 Years of Age

An AE was defined as 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. Percentage of participants reporting AEs from dose 3 to 1 month after dose 3 were reported in this outcome measure. Exact 2-sided CI 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.

Time frame: Phase 2/3: From Dose 3 to 1 Month after Dose 3

Phase 2/3: Percentage of Participants Reporting Serious Adverse Events From Dose 1 to 6 Months After Dose 2: >=2 to <5 Years of Age

An SAE was defined as any untoward medical occurrence that at any dose resulted in death, was life-threatening; resulted in persistent disability/incapacity; constituted a congenital anomaly/birth defect; was an important medical event; required inpatient hospitalization or prolongation of existing hospitalization, was a suspected transmission via a Pfizer product of an infectious agent, pathogenic or non-pathogenic. Exact 2-sided 95% CI was based on the Clopper and Pearson method.

Time frame: Phase 2/3: From Dose 1 to 6 Months after Dose 2

Phase 2/3: Percentage of Participants Reporting Serious Adverse Events From Dose 3 to 6 Months After Dose 3:>=2 to <5 Years of Age

An SAE was defined as any untoward medical occurrence that at any dose resulted in death, was life-threatening; resulted in persistent disability/incapacity; constituted a congenital anomaly/birth defect; was an important medical event; required inpatient hospitalization or prolongation of existing hospitalization, was a suspected transmission via a Pfizer product of an infectious agent, pathogenic or non-pathogenic. Exact 2-sided 95% CI was based on the Clopper and Pearson method.

Time frame: Phase 2/3: From Dose 3 to 6 Months after Dose 3

Phase 2/3: Percentage of Participants Reporting Adverse Events From Dose 1 to 1 Month After Dose 2 : >=6 Months to <2 Years of Age

An AE was defined as 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. Percentage of participants reporting AEs from dose 1 to 1 month after dose 2 were reported in this outcome measure. Exact 2-sided CI 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.

Time frame: Phase 2/3: From Dose 1 to 1 Month after Dose 2

Phase 2/3: Percentage of Participants Reporting Adverse Events From Dose 3 to 1 Month After Dose 3 : >=6 Months to <2 Years of Age

An AE was defined as 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. Percentage of participants reporting AEs from dose 3 to 1 month after dose 3 were reported in this outcome measure. Exact 2-sided CI 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.

Time frame: Phase 2/3: From Dose 3 to 1 Month after Dose 3

Phase 2/3: Percentage of Participants Reporting Serious Adverse Events From Dose 1 to 6 Months After Dose 2 : >=6 Months to <2 Years of Age

An SAE was defined as any untoward medical occurrence that at any dose resulted in death, was life-threatening; resulted in persistent disability/incapacity; constituted a congenital anomaly/birth defect; was important medical event; required inpatient hospitalization or prolongation of existing hospitalization, was a suspected transmission via a Pfizer product of an infectious agent, pathogenic or non-pathogenic. Exact 2-sided 95% CI was based on the Clopper and Pearson method.

Time frame: Phase 2/3: From Dose 1 to 6 Months after Dose 2

Phase 2/3: Percentage of Participants Reporting Serious Adverse Events From Dose 3 to 6 Months After Dose 3: >=6 Months to <2 Years of Age

An SAE was defined as any untoward medical occurrence that at any dose resulted in death, was life-threatening; resulted in persistent disability/incapacity; constituted a congenital anomaly/birth defect; was important medical event; required inpatient hospitalization or prolongation of existing hospitalization, was a suspected transmission via a Pfizer product of an infectious agent, pathogenic or non-pathogenic. Exact 2-sided 95% CI was based on the Clopper and Pearson method.

Time frame: Phase 2/3: From Dose 3 to 6 Months after Dose 3

Phase2/3:Geometric Mean Ratio(GMR)Based on GMT for SARS-CoV-2 Neutralizing Titers in Participants>=5 to<12 Years of Age Compared With Study C4591001 Phase 2/3 16 to 25 Years Historical Cohort:1 Month After Dose 2:Participants Without Evidence of Infection

GMRs and the corresponding 2-sided CIs were calculated by exponentiating the mean difference of the logarithm of the titers and the corresponding CIs (based on student t distribution). GMTs and 2-sided 95% CIs were calculated by exponentiating the mean logarithm of the titers and the corresponding CIs (based on the Student t distribution). Assay results below the lower limit of quantitation (LLOQ) were set to 0.5\*LLOQ. Results include those from a comparator group of C4591001 (NCT04368728) Phase 2/3 participants of the age 16 to 25 years who received 2 doses of original BNT162b2 30 mcg who had no serological or virological evidence of past SARS-CoV-2 infection and had no medical history of COVID-19 were also included. GMT is reported in descriptive analysis section and GMR is reported under statistical analysis.

Time frame: C4591007 (>=5 to <12 years): 1 Month after Dose 2 and C4591001 Historical cohort (16-25 years): 1 Month after Dose 2

Phase 2/3: Difference in Percentage of Participants Who Achieved Seroresponse in >=5 to <12 Years of Age Compared With Study C4591001 Phase 2/3 16 to 25 Years Historical Cohort: 1 Month After Dose 2: Participants Without Evidence of Infection

Seroresponse is defined as achieving a \>=4 fold rise from baseline (before Dose 1). Assay result below a postvaccination \>=4\*LLOQ is considered a seroresponse. Results include those from a comparator group of C4591001 (NCT04368728) Phase 2/3 participants who had no serological or virological evidence (prior to the 1-month post-Dose 2 blood sample collection) of past SARS-CoV-2 infection were included for this analysis. Percentage of participants with seroresponse is reported in descriptive analysis section and the difference in percentage of participants is reported under statistical analysis. Evaluable immunogenicity population included all eligible randomized participants who received the study intervention to which they were randomized, had a valid and determinate immunogenicity result within 28-42 days after the study vaccination, and had no other important protocol deviations as determined by the clinician.

Time frame: C4591007 (>=5 to <12 years): 1 Month after Dose 2 and C4591001 Historical cohort (16-25 years): 1 Month after Dose 2

Phase 2/3: GMR Based on GMT for SARS-CoV-2 Neutralizing Titers in Participants >=2 to <5 Years of Age Compared With Study C4591001 Phase 2/3 16 to 25 Years Historical Cohort: 1 Month After Dose 2: Participants Without Evidence of Infection

GMRs \& corresponding 2-sided CIs were calculated by exponentiating mean difference of logarithm of titers \& corresponding CIs(based on student t distribution).GMTs \& 2-sided 95% CIs were calculated by exponentiating mean logarithm of titers and corresponding CIs(based on the Student t distribution).Assay results below LLOQ were set to 0.5\*LLOQ.Results include those from comparator group of C4591001(NCT04368728) Phase2/3 participants of age 16-25 years who received 2 doses of original BNT162b2 30mcg who had no serological or virological evidence of past SARS-CoV-2 infection\& had no medical history of COVID-19 were also included.GMT is reported in descriptive analysis section \& GMR is reported under statistical analysis.EIP included all eligible randomized participants who received study intervention to which they were randomized,had a valid\&determinate immunogenicity result within 28-42 days after study vaccination,had no other important protocol deviations as determined by clinician.

Time frame: C4591007 (>=2 to <5 years): 1 Month after Dose 2 and C4591001 Historical cohort (16-25 years): 1 Month after Dose 2

Phase 2/3: Difference in Percentage of Participants Who Achieved Seroresponse in >=2 to <5 Years of Age Compared With Study C4591001 Phase 2/3 16 to 25 Years Historical Cohort: 1 Month After Dose 2: Participants Without Evidence of Infection

Seroresponse is defined as achieving a \>=4-fold rise from baseline (before Dose 1). Assay result below a postvaccination \>=4\*LLOQ is considered a seroresponse. Results include those from a comparator group of C4591001 (NCT04368728) Phase 2/3 participants who had no serological or virological evidence (prior to the 1-month post-Dose 2 blood sample collection) of past SARS-CoV-2 infection were included for this analysis. Percentage of participants with seroresponse is reported in descriptive analysis section and the difference in percentage of participants is reported under statistical analysis. Evaluable immunogenicity population included all eligible randomized participants who received the study intervention to which they were randomized, had a valid and determinate immunogenicity result within 28-42 days after the study vaccination, and had no other important protocol deviations as determined by the clinician.

Time frame: C4591007 (>=2 to <5 years): 1 Month after Dose 2 and C4591001 Historical cohort (16-25 years): 1 Month after Dose 2

Phase 2/3: GMR Based on GMT for SARS-CoV-2 Neutralizing Titers in Participants >=6 Months to <2 Years of Age Compared With Study C4591001 Phase 2/3 16 to 25 Years Historical Cohort: 1 Month After Dose 2: Participants Without Evidence of Infection

Time frame: C4591007 (>=6 Months to <2 years): 1 Month after Dose 2 and C4591001 Historical cohort (16-25 years): 1 Month after Dose 2

Phase 2/3: Difference in Percentage of Participants Who Achieved Seroresponse in >=6 Months to <2 Years of Age Compared With Study C4591001 Phase 2/3 16 to 25 Years Historical Cohort : 1 Month After Dose 2: Participants Without Evidence of Infection

Seroresponse is defined as achieving a \>=4-fold rise from baseline(before Dose 1). Assay result below a postvaccination \>=4\*LLOQ is considered a seroresponse. Results include those from a comparator group of C4591001 (NCT04368728) Phase 2/3 participants who had no serological or virological evidence (prior to the 1-month post-Dose 2 blood sample collection) of past SARS-CoV-2 infection were included for this analysis. Percentage of participants with seroresponse is reported in descriptive analysis section and the difference in percentage of participants is reported under statistical analysis. Evaluable immunogenicity population included all eligible randomized participants who received the study intervention to which they were randomized, had a valid and determinate immunogenicity result within 28-42 days after the study vaccination, and had no other important protocol deviations as determined by the clinician.

Time frame: C4591007 (>=6 Months to <2 years): 1 Month after Dose 2 and C4591001 Historical cohort (16-25 years): 1 Month after Dose 2

Phase 2/3:GMR Based on GMT for SARS-CoV-2 Neutralizing Titers at 1 Month After Dose 3 in Participants Aged>=2 to<5Years Compared With Study C4591001 Phase2/3 16 to 25 Years Historical Cohort(1 Month After Dose 2):Participants Without Evidence of Infection

GMRs and the corresponding 2-sided CIs were calculated by exponentiating the mean difference of logarithm of the titers and the corresponding CIs(based on student t distribution).GMTs \& 2-sided 95% CIs were calculated by exponentiating the mean logarithm of the titers and the corresponding CIs (based on the Student t distribution). Assay results below LLOQ were set to 0.5\*LLOQ. Results include those from comparator group of C4591001 (NCT04368728) Phase2/3 participants of age 16-25 years who received 2 doses of original BNT162b2 30 mcg who had no serological or virological evidence of past SARS-CoV-2 infection \& had no medical history of COVID-19 were also included. GMT is reported in descriptive analysis section \& GMR is reported under statistical analysis.

Time frame: C4591007 (>=2 to <5 years):1 Month after Dose 2 and C4591001 Historical cohort (16-25 years):1 Month after Dose 2

Phase 2/3:Difference in Percentage of Participants With Seroresponse in 2 to <5 Years of Age Compared With Study C4591001 Phase 2/3 16 to 25 Years of Age Historical Cohort: Participants Without Evidence of Infection

Seroresponse is defined as achieving a \>=4-fold rise from baseline(before Dose 1). Assay result below a postvaccination \>=4\*LLOQ is considered a seroresponse.Results include those from a comparator group of C4591001 (NCT04368728) Phase 2/3 participants who had no serological or virological evidence (prior to the 1-month post-Dose 2 blood sample collection) of past SARS-CoV-2 infection were included for this analysis. Percentage of participants with seroresponse is reported in descriptive analysis section and the difference in percentage of participants is reported under statistical analysis. Evaluable immunogenicity population included all eligible randomized participants who received the study intervention to which they were randomized, had a valid and determinate immunogenicity result within 28-42 days after the study vaccination, and had no other important protocol deviations as determined by the clinician.

Time frame: C4591007 (>=2 to <5 years): 1 Month after Dose 3 and C4591001 Historical cohort (16-25 years): 1 Month after Dose 2

Phase2/3:GMR Based on GMT for SARS-CoV-2 Neutralizing Titers at 1 Month After Dose3 in Participants Aged 6Month to 2Year Compared With Study C4591001 Phase2/3 16 to 25Years Historical Cohort(1 Month After Dose 2):Participants Without Evidence of Infection

GMRs and the corresponding 2-sided CIs were calculated by exponentiating the mean difference of the logarithm of titers and the corresponding CIs (based on student t distribution). GMTs and the 2-sided 95% CIs were calculated by exponentiating the mean logarithm of the titers and the corresponding CIs (based on the Student t distribution). Assay results below LLOQ were set to 0.5\*LLOQ. Results include those from comparator group of C4591001 (NCT04368728) Phase2/3 participants of age 16-25 years who received 2 doses of original BNT162b2 30mcg who had no serological or virological evidence of past SARS-CoV-2 infection\& had no medical history of COVID-19 were also included. GMT is reported in descriptive analysis section \& GMR is reported under statistical analysis.

Time frame: C4591007 (>=6 months to <2 years):1 Month after Dose 3 and C4591001 Historical cohort (16-25 years):1 Month after Dose 2

Phase 2/3:Difference in Percentage of Participants With Seroresponse in 6 Months to <2 Years (1 Month After Dose 3) Compared With Study C4591001 Phase 2/3 16 to 25 Years Historical Cohort (1 Month After Dose 2): Participants Without Evidence of Infection

Seroresponse is defined as achieving a \>=4-fold rise from baseline(before Dose 1). Assay result below a postvaccination \>=4\*LLOQ is considered a seroresponse. Results include those from a comparator group of C4591001(NCT04368728)Phase 2/3 participants who had no serological or virological evidence (prior to the 1-month post-Dose 2 blood sample collection) of past SARS-CoV-2 infection were included for this analysis. Percentage of participants with seroresponse is reported in descriptive analysis section and the difference in percentage of participants is reported under statistical analysis. Evaluable immunogenicity population included all eligible randomized participants who received the study intervention to which they were randomized, had a valid and determinate immunogenicity result within 28-42 days after the study vaccination, and had no other important protocol deviations as determined by the clinician.

Time frame: C4591007 (>=6 Months to <2 years):1 Month after Dose 3 and C4591001 Historical cohort (16-25 years):1 month after Dose 2

Secondary Outcomes

Phase 1: Geometric Mean Titer (GMT) of Severe Acute Respiratory Syndrome Coronavirus 2 Neutralizing Titer at 7 Days After Dose 2: >=6 Months to <2 Years of Age: Participants Without Evidence of Infection

GMT of SARS-CoV-2 neutralizing titer after the study vaccination was reported in this outcome measure. GMTs and the corresponding 2-sided CIs were calculated by exponentiating the mean logarithm of the titer and the corresponding CIs(based on Student's t distribution). Assay results below the LLOQ were set to 0.5\*LLOQ. Evaluable Immunogenicity Population consisted of all eligible randomized participants who received 2 doses with the same dose level to which they were randomized, with Dose 2 received within the predefined window, had at least 1 valid and determinate immunogenicity result after Dose 2 from the blood sample collected within an appropriate window after Dose 2(within 6-8 days after Dose 2 for Phase 1), and had no other important protocol deviations as determined by the clinician.

Time frame: Phase 1: 7 days post Dose 2

Phase 1: GMT of Severe Acute Respiratory Syndrome Coronavirus 2 Neutralizing Titer at 7 Days After Dose 2: >=2 to <5 Years of Age: Participants Without Evidence of Infection

GMT of SARS-CoV-2 neutralizing titers after the study vaccination was reported in this outcome measure. GMT and the corresponding 2-sided CIs were calculated by exponentiating the mean logarithm of the titer and the corresponding CIs(based on Student's t distribution).Assay results below the LLOQ were set to 0.5\*LLOQ. Evaluable Immunogenicity Population consisted of all eligible randomized participants who received 2 doses with the same dose level to which they were randomized, with Dose 2 received within the predefined window, had at least 1 valid and determinate immunogenicity result after Dose 2 from the blood sample collected within an appropriate window after Dose 2(within 6-8 days after Dose 2 for Phase 1), and had no other important protocol deviations as determined by the clinician.

Time frame: Phase 1: 7 days post Dose 2

Phase 1: GMT of Severe Acute Respiratory Syndrome Coronavirus 2 Neutralizing Titer at 7 Days After Dose 2: >=5 to <12 Years of Age: Participants Without Evidence of Infection

Time frame: Phase 1: 7 days post Dose 2

Phase 2/3: Geometric Mean Titer - Neutralizing Titer (NT50) : 5 to <12 Years of Age: Before Dose 1 and 1 Month After Dose 2:Participants Without Evidence of Infection

GMTs and the corresponding 2-sided CIs were calculated by exponentiating the mean logarithm of the titer and the corresponding CIs (based on Student's t distribution). Assay results below the LLOQ were set to 0.5 × LLOQ. Participants included in this analysis had no serological or virological evidence of past SARS-CoV-2 infection or had no medical history of COVID-19. Evaluable immunogenicity population included all eligible randomized participants who received the study intervention to which they were randomized, had a valid and determinate immunogenicity result within 28-42 days after the study vaccination, and had no other important protocol deviations as determined by the clinician.

Time frame: Phase 2/3: Before Dose 1 and 1 Month after Dose 2

Phase 2/3: Geometric Mean Titer - NT50: 5 to <12 Years of Age: Pre-Dose 3 and 1 Month After Dose 3:Participants Without Evidence of Infection

GMTs and the corresponding 2-sided CIs were calculated by exponentiating the mean logarithm of the titer and the corresponding CIs (based on Student's t distribution). Assay results below the LLOQ were set to 0.5 \*LLOQ. Participants included in this analysis had no serological or virological evidence of past SARS-CoV-2 infection or had no medical history of COVID-19. Evaluable immunogenicity population (EIP) included all eligible randomized participants who received the study intervention to which they were randomized, had a valid and determinate immunogenicity result within 28-42 days after the study vaccination, and had no other important protocol deviations as determined by the clinician.

Time frame: Phase 2/3: From Dose 3 set: Pre-Dose 3 and 1 Month after Dose 3

Phase 2/3: Geometric Mean Titer - NT50:2 to <5 Years of Age: Pre-Dose 1, Pre-Dose 3 and 1 Month After Dose 3: Participants Without Evidence of Infection

Time frame: Phase 2/3: From Pre-Dose 1, Pre-Dose 3 and 1 Month After Dose 3

Phase 2/3: Geometric Mean Titer- NT50:6 Months to <2 Years of Age: Pre-Dose 1, Pre-Dose 3 and 1 Month After Dose 3: Participants Without Evidence of Infection

Time frame: Phase 2/3: From Pre-Dose 1, Pre-Dose 3 and 1 Month After Dose 3

Phase 2/3: Geometric Mean Fold Rise (GMFR) of SARS-CoV-2 Neutralizing Titers From Dose 1 to 1 Month After Dose 2: >=5 to 12 Years of Age: Participants Without Evidence of Infection

GMFR of SARS-CoV-2 neutralizing titers from dose 1 to 1 month after dose 2 were reported in this outcome measure. GMFRs and 2-sided 95% CIs were calculated by exponentiating the mean logarithm of fold rises and the corresponding CIs (based on the Student t distribution). Participants included in this analysis had no serological or virological evidence of past SARS-CoV-2 infection or had no medical history of COVID-19. Assay results below the LLOQ were set to 0.5\* LLOQ in the analysis.

Time frame: Phase 2/3: From Dose 1 to 1 Month after Dose 2

Phase 2/3:GMFR of SARS-CoV-2 Neutralizing Titers From Dose 3 to 1 Month After Dose 3: >=5 to 12 Years of Age: Participants Without Evidence of Infection

GMFR of SARS-CoV-2 neutralizing titers from before Dose 3 to 1 month after Dose were reported in this outcome measure. GMFRs and 2-sided 95% CIs were calculated by exponentiating the mean logarithm of fold rises and the corresponding CIs (based on the Student t distribution). Assay results below the LLOQ were set to 0.5\*LLOQ in the analysis. Participants included in this analysis had no serological or virological evidence of past SARS-CoV-2 infection or had no medical history of COVID-19. Evaluable immunogenicity population included all eligible randomized participants who received the study interventions to which they were randomized, had a valid and determined immunogenicity result within 28-42 days after Dose 3, and had no other important protocol deviations as determined by the clinicians.

Time frame: Phase 2/3: From Dose 3 to 1 Month after Dose 3

Phase 2/3: GMFR of SARS-CoV-2 Neutralizing Titers From Before Dose 1 to Pre-Dose 3 and 1 Month After Dose 3: >=2 to 5 Years of Age: Participants Without Evidence of Infection

GMFRs and 2-sided 95% CIs were calculated by exponentiating the mean logarithm of fold rises and the corresponding CIs(based on the Student t distribution). Participants included in this analysis had no serological or virological evidence of past SARS-CoV-2 infection and had no medical history of COVID-19 infection.Assay results below the LLOQ were set to 0.5\*LLOQ in the analysis.

Time frame: Phase 2/3: From before dose 1 to Pre-Dose 3, 1 Month After Dose 3

Phase 2/3: GMFR of SARS-CoV-2 Neutralizing Titers From Before Dose 1 to Pre-Dose 3 and 1 Month After Dose 3: >=6 Months to 2 Years of Age: Participants Without Evidence of Infection

GMFRs and 2-sided 95% CIs were calculated by exponentiating the mean logarithm of fold rises and the corresponding CIs (based on the Student t distribution). Assay results below the LLOQ were set to 0.5\*LLOQ in the analysis. Participants included in this analysis had no serological or virological evidence of past SARS-CoV-2 infection prior to the 1-month post-Dose 2.

Time frame: Phase 2/3: From before dose 1 to Pre-Dose 3, 1 Month After Dose 3

Phase 2/3: COVID-19 Incidence From 7 Days After Dose 2 to Prior to Dose 3 Per 1000 Person-Years of Blinded Follow-up in Participants Without Serological or Virological Evidence: >=5 to <12 Years of Age

COVID-19 incidence from 7 days after dose 2 to prior to dose 3 without the evidence of infection were reported in this outcome measure. Evaluable efficacy population included all eligible randomized participants who received all vaccination as randomized, with Dose 2 received within the predefined window (within 19-42 days after Dose 1) and have no other important protocol deviations as determined by clinician on or before 7 days after Dose 2.

Time frame: Phase 2/3: From 7 days after Dose 2 to prior to Dose 3 (Surveillance time [1000 person-years]: BNT162b2 - 0.591; Placebo - 0.292)

Phase 2/3: COVID-19 Incidence From 7 Days After Dose 2 to Prior to Dose 3 Per 1000 Person-Years of Blinded Follow-up in Participants With or Without Serological or Virological Evidence: >=5 to <12 Years of Age

COVID-19 incidence from 7 days after dose 2 to prior to dose 3 with or without the evidence of infection were reported in this outcome measure. Evaluable efficacy population included all eligible randomized participants who received all vaccination as randomized, with Dose 2 received within the predefined window (within 19-42 days after Dose 1) and have no other important protocol deviation as determined by clinician on or before 7 days after Dose 2.

Time frame: Phase 2/3: From 7 Days After Dose 2 to prior to Dose 3 (Surveillance time [1000 person-years]: BNT162b2 - 0.653; Placebo - 0.326)

Phase 2/3: COVID-19 Incidence From 7 Days After Dose 3 Per 1000 Person-Years of Blinded Follow-up in Participants Without Serological or Virological Evidence: >=6 Months to <5 Years of Age

COVID-19 incidence from 7 days after dose 3 without the evidence of infection were reported in this outcome measure. Evaluable efficacy population included all eligible randomized participants who received all vaccination as randomized, with Dose 3 received within the predefined window (within 19-42 days after Dose 2) and have no other important protocol deviations as determined by clinician on or before 7 days after Dose 3.

Time frame: Phase 2/3: From 7 Days After Dose 3 (Surveillance time [1000 person-years]: BNT162b2 - 0.124; Placebo - 0.054)

Phase 2/3: COVID-19 Incidence From 7 Days After Dose 3 Per 1000 Person-Years of Blinded Follow-up in Participants With or Without Serological or Virological Evidence: >=6 Months to <5 Years of Age

Time frame: Phase 2/3: From 7 Days After Dose 3 (Surveillance time [1000 person-years]: BNT162b2 - 0.149; Placebo - 0.067)