A Study to Evaluate VXA-CoV2-3.3 COVID-19 Vaccine Against Currently Approved/Authorized mRNA COVID-19 Injectable Booster Vaccine in Adults Previously Immunized Against COVID-19 Infection
← catalyst calendarNCT06672055 · readout ≤ 284 d
Sponsored by Vaxart (industry) · VXRT — their whole pipeline →.
Phase
Phase 2
Status
Active, not recruiting
Study type
Interventional
Design
Randomized · Double · Prevention
Enrollment
5,485estimated
Sites
145
Country
United States
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 | 2024-10-08 | actual | When the study began enrolling |
| Primary completion | May 2027 | estimated | The date the last participant is measured for the primary outcome — the readout window |
| Study completion | May 2027 | estimated | The whole study's end, after follow-up |
| First posted | 2024-11-04 | actual | When this record first appeared on the registry |
| Results posted | — | When the sponsor posted results to the registry | |
| Record updated | 2026-06-25 | actual | The sponsor's own last edit to this record — every projection above is as current as this date |
What it studies
Conditions
- SARS-CoV2
- COVID-19
Interventions
- Biological: VXA-CoV2-3.1
- Biological: COMIRNATY® — also filed as Pfizer-BioNTech mRNA Vaccine
- Biological: VXA-CoV2-3.3
Primary outcomes
what the primary-completion date above is the date OFKP.2 Cohorts: Percentage of Participants with First Occurrence of Symptomatic Polymerase Chain Reaction (PCR)-Positive COVID-19 at 14 Days Post-vaccination
measured Up to approximately Day 14
KP.2 Cohorts: Percentage of Participants with First Occurrence of Symptomatic PCR-Positive COVID-19 at 12 Months Post-vaccination
measured Up to approximately 12 months
XBB Sentinel Cohorts: Percentage of Participants who Experience any Solicited Local Reactogenicity Through 7 Days Post-vaccination
measured Up to approximately Day 7
XBB Sentinel Cohorts: Percentage of Participants who Experience any Solicited Systemic Reactogenicity Through 7 Days Post-vaccination
measured Up to approximately Day 7
XBB Sentinel Cohorts: Percentage of Participants who Experience Unsolicited Adverse Events (AEs) Through 30 Days Post-vaccination
measured Up to approximately Day 30
XBB Sentinel Cohorts: Percentage of Participants who Experience Treatment-emergent Adverse Events (TEAEs) Through 12 Months Post-vaccination
measured Up to approximately 12 months
XBB Sentinel Cohorts: Percentage of Participants With any Clinically Significant Abnormal Safety Laboratory Results Within 7 Days Pots-vaccination
measured Up to approximately Day 7
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