A Study to Learn About Variant-Adapted COVID-19 RNA Vaccine Candidate(s) in Healthy Children
← catalyst calendarSponsored by BioNTech SE (industry) · BNTX — their whole pipeline →. With Pfizer.
Phase
Phase 3
Status
Completed
Study type
Interventional
Design
Non randomized · None · Prevention
Enrollment
4,338actual
Sites
96
Countries
Brazil, Mexico, Puerto Rico +2
Every value on this page is a field the sponsor filed with ClinicalTrials.gov, reproduced. Dates are their own estimates, revised as a study runs, unless the registry marks them actual. sources →
Source: ClinicalTrials.gov, retrieved 2026-08-19
Dates
each axis at the precision it was filed, with the registry's own basis| Date | Filed | Basis | What it is |
|---|---|---|---|
| Start | 2022-09-23 | actual | When the study began enrolling |
| Primary completion | 2026-07-10 | actual | The date the last participant is measured for the primary outcome — the readout window |
| Study completion | 2026-07-10 | actual | The whole study's end, after follow-up |
| First posted | 2022-09-16 | actual | When this record first appeared on the registry |
| Results posted | — | When the sponsor posted results to the registry | |
| Record updated | 2026-08-06 | actual | The sponsor's own last edit to this record — every projection above is as current as this date |
What it studies
Conditions
- SARS-CoV-2 Virus
- Severe Acute Respiratory Syndrome Coronavirus 2
- COVID-19
Interventions
- Biological: Bivalent BNT162b2 (original/Omicron BA.4/BA.5) 3 microgram dose
- Biological: Bivalent BNT162b2 (original/Omicron BA.4/BA.5) 6 microgram dose
- Biological: Bivalent BNT162b2 (original/Omicron BA.4/BA.5) 10 microgram dose
- Biological: Variant-adapted BNT162b2 (Omicron XBB.1.5) 3 microgram dose
- Biological: Variant-adapted BNT162b2 (Omicron XBB.1.5) 6 microgram dose
- Biological: Variant-adapted BNT162b2 (Omicron XBB.1.5) 10 microgram dose
- Biological: Variant-adapted BNT162b2 (Omicron KP.2) 10 microgram dose
Primary outcomes
what the primary-completion date above is the date OFSubstudy A (SSA) - Ph 1 dose finding, percentage of participants reporting local reactions
measured for up to 7 days following Dose 1, Dose 2, Dose 3 and Dose 4
SSA - Ph 1 dose finding, percentage of participants reporting systemic events
measured for up to 7 days following Dose 1, Dose 2, Dose 3 and Dose 4
SSA - Ph 1 dose finding, percentage of participants reporting adverse events
measured from Dose 1 to 1 month after Dose 3 and from Dose 4 to 1 month after Dose 4
SSA - Ph 1 dose finding, percentage of participants reporting serious adverse events
measured from Dose 1 to 6 months after the last dose
SSA - Ph 2/3, percentage of participants reporting local reactions
measured for up to 7 days following Dose 1 (for Groups 1 through 6), Dose 2 (for Groups 1, 2, 3, and 6), and Dose 3 (for Group 3)
SSA - Ph 2/3, percentage of participants reporting systemic events
measured for up to 7 days following Dose 1 (for Groups 1 through 6), Dose 2 (for Groups 1, 2, 3, and 6), and Dose 3 (for Group 3)
SSA - Ph 2/3, percentage of participants reporting adverse events
measured from Dose 1 to 1 month after the last dose
SSA - Ph 2/3, percentage of participants reporting serious adverse events
measured from Dose 1 to 6 months after the last dose
SSA - Ph 2/3, noninferiority with respect to ratio of the geometric mean of SARS-CoV-2 Omicron XBB.1.5-neutralizing titers in participants ≥6 months to <2 years of age
measured At 1 month after 2 doses of BNT162b2 (Omicron XBB.1.5) 10 microgram (on a 0- and 8-week schedule) to 1 month after 3 doses (on a 0-, 3-, and 11-week schedule) of BNT162b2 (Omicron XBB.1.5) 3 microgram
SSA - Ph 2/3, noninferiority with respect to seroresponse rate to the Omicron XBB.1.5 strain titers in participants ≥6 months to <2 years of age
measured At 1 month after 2 doses of BNT162b2 (Omicron XBB.1.5) 10 microgram (on a 0- and 8-week schedule) and at 1 month after 3 doses (on a 0-, 3-, and 11-week schedule) of BNT162b2 (Omicron XBB.1.5) 3 microgram
SSA - Ph 2/3, noninferiority with respect to ratio of the geometric mean of SARS-CoV-2 Omicron XBB.1.5-neutralizing titers in participants ≥2 to <5 years of age
measured At 1 month after 1 dose of BNT162b2 (Omicron XBB.1.5) 10 microgram in participants ≥2 to <5 years of age to 1 month after 3 doses (on a 0/3/11-week schedule) of BNT162b2 (Omicron XBB.1.5) 3 microgram in participants ≥6 months to <2 years of age
SSA - Ph 2/3, noninferiority with respect to seroresponse rate to the Omicron XBB.1.5 strain in participants ≥2 to <5 years of age
measured At 1 month after 1 dose of BNT162b2 (Omicron XBB.1.5) 10 microgram in participants ≥2 to <5 years of age and at 1 month after 3 doses (0/3/11-week schedule) of BNT162b2 (Omicron XBB.1.5) 3 microgram in participants ≥6 months to <2 years of age
Substudy B (SSB) - percentage of participants reporting local reactions
measured for up to 7 days following Dose 1 (for Groups 1, 2 and 3) and Dose 2 (for Group 1)
SSB - percentage of participants reporting systemic events
measured for up to 7 days following Dose 1 (for Groups 1, 2 and 3) and Dose 2 (for Group 1)
SSB - percentage of participants reporting adverse events
measured from the first study vaccination to 1 month after the first study vaccination (for Groups 1, 2, and 3), and from the second study vaccination to 1 month after the second study vaccination (for Group 1 only)
SSB - percentage of participants reporting serious adverse events
measured from Dose 1 to 6 months after the last dose
SSB - superiority with respect to ratio of the geometric mean of SARS-CoV-2 Omicron BA.4/BA.5-neutralizing titers in participants ≥6 months to <5 years of age
measured at 1 month after Dose 4 for Group 2 participants who received 3 prior doses of BNT162b2 3 µg and a fourth dose of bivalent BNT162b2 to 1 month after Dose 3 in Study C4591007 participants ≥6 months to <5 years of age who received 3 doses of BNT162b2 3 µg
SSB - noninferiority with respect to seroresponse rate to the Omicron BA.4/BA.5 strain in participants ≥6 months to <5 years of age
measured at 1 month after Dose 4 for Group 2 participants who received 3 prior doses of BNT162b2 3 µg and a fourth dose of bivalent BNT162b2 to 1 month after Dose 3 in Study C4591007 participants ≥6 months to <5 years of age who received 3 doses of BNT162b2 3 µg
Substudy C (SSC) - Ph 1 dose finding, percentage of participants reporting local reactions
measured for up to 7 days following Dose 1
SSC - Ph 1 dose finding, percentage of participants reporting systemic events
measured for up to 7 days following Dose 1
SSC - Ph 1 dose finding, percentage of participants reporting adverse events
measured 1 month after Dose 1
SSC - Ph 1 dose finding, percentage of participants reporting serious adverse events
measured 6 months after Dose 1
SSC - Ph 1 dose finding - geometric mean titers elicited by prophylactic bivalent BNT162b2 at each dose level given as a fourth dose in participants ≥6 months to <5 years of age
measured At baseline (before Dose 1) and 1 month after Dose 1
SSC - Ph 1 dose finding - geometric mean fold rise elicited by prophylactic bivalent BNT162b2 at each dose level given as a fourth dose in participants ≥6 months to <5 years of age
measured At baseline (before Dose 1) and 1 month after Dose 1
SSC - Ph 1 dose finding - percentage of participants with seroresponse elicited by prophylactic bivalent BNT162b2 at each dose level given as a fourth dose in participants ≥6 months to <5 years of age
measured At baseline (before Dose 1) and 1 month after Dose 1
Substudy D (SSD) - percentage of participants reporting local reactions
measured for up to 7 days following Dose 1
SSD - percentage of participants reporting systemic events
measured for up to 7 days following Dose 1
SSD - percentage of participants reporting adverse events
measured 1 month after Dose 1
SSD - percentage of participants reporting serious adverse events
measured 6 months after Dose 1
SSD - the ratio of the geometric mean of SARS-CoV-2 Omicron BA.4/BA.5-neutralizing titers in participants ≥5 to <12 years of age
measured at 1 month after Dose 4 for participants who received 3 prior doses of BNT162b2 10 μg and a fourth dose of bivalent BNT162b2 to those at 1 month after Dose 3 for Study C4591007 Phase 2/3 participants who received 3 doses of BNT162b2 10 μg
SSD - difference in percentages of participants with seroresponse to the Omicron BA.4/BA.5 strain in participants ≥5 to <12 years of age
measured at 1 month after bivalent BNT162b2 as a fourth dose for participants who received 3 prior doses of BNT162b2 10 µg and at 1 month after a third dose of BNT162b2 10 µg for Study C4591007 Phase 2/3 participants who received 3 doses of BNT162b2 10 µg
Substudy E (SSE) - percentage of participants reporting local reactions
measured for up to 7 days following Dose 1
SSE - percentage of participants reporting systemic events
measured for up to 7 days following Dose 1
SSE - percentage of participants reporting adverse events
measured from Dose 1 to 1 month after Dose 1
SSE - percentage of participants reporting serious adverse events
measured from Dose 1 to 6 months after Dose 1
SSE - Ratio of the geometric mean of SARS-CoV-2 Omicron XBB.1.5-neutralizing titers
measured At 1 month after 1 dose of BNT162b2 (Omi XBB.1.5) 10 microgram in participants ≥5 to 12 years of age to 1 month after 1 dose of BNT162b2 (Omi XBB.1.5) 30 microgram in participants ≥12 years of age from study C4591054 Substudy A
SSE - difference in percentage of participants with seroresponse to Omicron XBB.1.5
measured At 1 month after 1 dose of BNT162b2 (Omi XBB.1.5) 10 microgram in participants ≥5 to 12 years of age and 1 month after 1 dose of BNT162b2 (Omi XBB.1.5) 30 microgram in participants ≥12 years of age from study C4591054 Substudy A
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