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

October 20, 2025 updated by: Vaxart

A Phase 2b, Double-Blind, Multi-Center, Randomized, Comparator-Controlled Trial to Determine the Relative Efficacy, Safety, and Immunogenicity of the Investigational Oral SARS-CoV-2 Vaccine Tablet Against Currently Approved/Authorized mRNA COVID-19 Injectable Booster Vaccine in Adults Previously Immunized Against COVID-19 Infection

The primary objective of the study is to determine the relative efficacy of the investigational oral severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) vaccine tablet VXA-CoV2-3.3 compared to a currently recommended vaccine for the prevention of symptomatic Coronavirus Disease 2019 (COVID-19).

In order to represent a more recently circulating SARS-CoV-2 variant, the main study endpoints will now evaluate the VXA-CoV2-3.3 (KP.2 strain) vaccine, and not the VXA-CoV2-3.1 (XBB.1.5 strain) vaccine.

Study Overview

Status

Active, not recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

10400

Phase

Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

United States
- Alabama
  - Anniston, Alabama, United States, 36207
    - Pinnacle Research Group
  - Birmingham, Alabama, United States, 35209-8401
    - Core Clinical Trials - Central Alabama Research LLC
  - Mobile, Alabama, United States, 36608
    - Coastal Clinical Research
- Arizona
  - Glendale, Arizona, United States, 85308
    - Avacare - Lenzmeier Family Medicine
  - Mesa, Arizona, United States, 85213
    - Desert Clinical Research
  - Phoenix, Arizona, United States, 85044
    - Foothills Research Center
  - Phoenix, Arizona, United States, 85020
    - Velocity Clinical Research - MedPharmics - Phoenix
  - Tempe, Arizona, United States, 85283
    - Avacare (CCT) - Fiel Family & Sports Medicine
- Arkansas
  - Little Rock, Arkansas, United States, 72205
    - Baptist Health Center for Clinical Research - Little Rock
- California
  - Cerritos, California, United States, 90703
    - Elligo Health Research (BTC/ClinEdge) - Core Healthcare Group
  - Chula Vista, California, United States, 91911
    - Velocity Clinical Research - Chula Vista (eStudySite - Chula Vista)
  - Colton, California, United States, 92324
    - Avacare - Benchmark Research - SOCAL-Colton
  - Cypress, California, United States, 90630
    - Altasciences Los Angeles (Formerly WCCT Global)
  - Fountain Valley, California, United States, 92708
    - Ark Clinical Research - Fountain Valley, CA
  - La Mesa, California, United States, 91942
    - Velocity Clinical Research - San Diego (eStudySite - La Mesa)
  - Long Beach, California, United States, 90815
    - Ark Clinical Research - Long Beach, CA
  - Los Angeles, California, United States, 90057
    - Velocity Clinical Research (National Research Institute) - Panorama City
  - Sacramento, California, United States, 95821
    - Northern California Research
  - Sacramento, California, United States, 95864
    - Avacare - Benchmark Research - Sacramento
  - Santa Ana, California, United States, 92704
    - Velocity Clinical Research - Gardena
- Colorado
  - Colorado Springs, Colorado, United States, 80909
    - Elite Research Network (ERN) - Legacy Clinical Trials
  - Fort Collins, Colorado, United States, 80528
    - Tekton Research - Fort Collins
  - Lakewood, Colorado, United States, 80228
    - Avacare - Critical Care, Pulmonary and Sleep Associates
  - Longmont, Colorado, United States, 80501
    - Tekton Research - Colorado - Longmont
  - Wheat Ridge, Colorado, United States, 80033
    - Paradigm Clinical Research - Wheat Ridge
- Connecticut
  - Stamford, Connecticut, United States, 06905
    - Stamford Therapeutics Consortium
  - Waterbury, Connecticut, United States, 06708
    - Chase Medical Research
- District of Columbia
  - Washington D.C., District of Columbia, United States, 20016
    - Velocity Clinical Research - Washington DC
- Florida
  - Coral Gables, Florida, United States, 33134
    - AMR - Miami (Clinical Research of South Florida)
  - Doral, Florida, United States, 33166
    - Universal Axon Clinical Research
  - Edgewater, Florida, United States, 32132
    - Velocity Clinical Research - New Smyrna Beach
  - Fleming Island, Florida, United States, 32003
    - Fleming Island Center for Clinical Research
  - Fort Myers, Florida, United States, 33912
    - AMR - Fort Myers - Clinical Physiology Associates
  - Hallandale, Florida, United States, 33009
    - Velocity Clinical Research - Hallandale Beach (MD Clinical)
  - Inverness, Florida, United States, 34452
    - ENCORE - Nature Coast Clinical Research Inverness
  - Jacksonville, Florida, United States, 32216
    - Jacksonville Center for Clinical Research
  - Jacksonville, Florida, United States, 32205
    - ENCORE - Westside Center for Clinical Research
  - Lake Worth, Florida, United States, 33462
    - Headlands Research - JEM Research - Lake Worth
  - Lakeland, Florida, United States, 33803
    - Accel Research Sites - Lakeland
  - Largo, Florida, United States, 33777
    - Accel Research Sites (ARS) - St. Petersburg - Largo
  - Maitland, Florida, United States, 32751
    - Accel Research Sites - Maitland
  - Maitland, Florida, United States, 32751
    - K2 Medical Research - Maitland
  - Miami, Florida, United States, 33173
    - SRA Trials LLC - Miami Clinical Trials at Suncoast Research Associates
  - New Port Richey, Florida, United States, 34652
    - Atlas Clinical Research - Suncoast Clinical Research - Pasco County
  - North Miami Beach, Florida, United States, 33169
    - Biscayne Clinical Research
  - Orlando, Florida, United States, 32806
    - K2 Medical Research - South Orlando
  - Plantation, Florida, United States, 33322
    - Boca Raton Clinical Research (BRCR) Global - Weston
  - Saint Augustine, Florida, United States, 32086
    - ENCORE - St. Johns Center for Clinical Research
  - St. Petersburg, Florida, United States, 33704
    - IMA Clinical Research - St. Petersburg
- Georgia
  - Columbus, Georgia, United States, 31904
    - hyperCORE - Centricity Research Columbus
  - Fayetteville, Georgia, United States, 30214
    - Javara Research - Privia Medical Group Georgia
  - Fayetteville, Georgia, United States, 30214
    - Privia Health - SouthCoast Health
  - Lilburn, Georgia, United States, 30047
    - Avacare (CCT) - Lifeline Primary Care
  - Rincon, Georgia, United States, 31326
    - hyperCORE - Centricity Research (IACT Health) - Rincon
  - Savannah, Georgia, United States, 31406
    - Velocity Clinical Research - Savannah
- Idaho
  - Meridian, Idaho, United States, 83642
    - Velocity Clinical Research - Boise (Meridian)
- Illinois
  - Chicago, Illinois, United States, 60602
    - IMA Clinical Research - Chicago
  - Lombard, Illinois, United States, 60148
    - Accellacare - Duly Health and Care
- Indiana
  - Valparaiso, Indiana, United States, 46383
    - Velocity Clinical Research - Valparaiso (Buynak Clinical Research)
- Iowa
  - Ames, Iowa, United States, 50010
    - Accellacare - McFarland Clinic
  - Sioux City, Iowa, United States, 51106
    - Velocity (Meridian) Clinical Research - Sioux City
- Kansas
  - El Dorado, Kansas, United States, 67042
    - AMR - El Dorado - Heartland Research Associates
  - Lenexa, Kansas, United States, 66219
    - Johnson County Clin-Trials
  - Newton, Kansas, United States, 67114
    - AMR - Newton (Heartland Research Associates)
  - Wichita, Kansas, United States, 67205
    - AMR - Wichita West - Heartland Research Associates
  - Wichita, Kansas, United States, 67207
    - AMR - Wichita East - Heartland Research Associates
- Kentucky
  - Lexington, Kentucky, United States, 40509
    - AMR - Lexington (Central Kentucky Research Associates)
- Louisiana
  - Baton Rouge, Louisiana, United States, 70809
    - Velocity (Meridian) Clinical Research - Baton Rouge
  - Covington, Louisiana, United States, 70433
    - Avacare - Benchmark Research - New Orleans-North Shore
  - Covington, Louisiana, United States, 70433
    - Velocity Clinical Research - MedPharmics - Covington
  - Gretna, Louisiana, United States, 70053
    - Boca Raton Clinical Research (BRCR) Global USA - New Orleans
  - Lafayette, Louisiana, United States, 70508
    - Velocity Clinical Research - MedPharmics - Lafayette
  - Metairie, Louisiana, United States, 70006
    - Avacare - Benchmark Research - Metairie
  - New Orleans, Louisiana, United States, 70119
    - AMR - New Orleans - Center for Clinical Research
- Maryland
  - Annapolis, Maryland, United States, 21401
    - Javara Research - Privia Medical Group Mid-Atlantic - Annapolis
  - Baltimore, Maryland, United States, 21201
    - Pharmaron
  - Rockville, Maryland, United States, 20850
    - Avacare (CCT) - Advanced Primary and Geriatric Care
  - Rockville, Maryland, United States, 20854
    - Velocity (Meridian) Clinical Research - Rockville
- Minnesota
  - Mankato, Minnesota, United States, 56001
    - Javara Research - Mankato Clinic
- Mississippi
  - Gulfport, Mississippi, United States, 39503
    - Velocity Clinical Research - MedPharmics - Gulfport
- Missouri
  - Kansas City, Missouri, United States, 64151
    - Avacare (CCT) - Clay Platte Family Medicine Clinic
- Nebraska
  - Elkhorn, Nebraska, United States, 68022
    - Avacare (CCT) - Skyline Medical Center
  - Grand Island, Nebraska, United States, 68803
    - Velocity (Meridian) Clinical Research - Grand Island
  - Lincoln, Nebraska, United States, 68516
    - Be Well Clinical Studies - Nebraska
  - Omaha, Nebraska, United States, 68134
    - Velocity (Meridian) Clinical Research - Omaha
- New Hampshire
  - Portsmouth, New Hampshire, United States, 03801
    - hyperCORE - ActivMed Practices and Research - Portsmouth
- New Jersey
  - Jersey City, New Jersey, United States, 07306
    - DM Clinical Research - Jersey City
- New Mexico
  - Albuquerque, New Mexico, United States, 87107
    - Velocity Clinical Research - Alburquerque
  - Santa Fe, New Mexico, United States, 87505
    - AXCES Research & Health - Santa Fe
- New York
  - Albany, New York, United States, 12205
    - IMA Clinical Research - Albany, Suite 202
  - East Syracuse, New York, United States, 13057
    - Velocity Clinical Research - Syracuse
  - New York, New York, United States, 10036
    - IMA Clinical Research - Manhattan
  - Rochester, New York, United States, 14609
    - Atlas Clinical Research - Rochester Clinical Research
- North Carolina
  - Cary, North Carolina, United States, 27518
    - Cary Medical Group
  - Durham, North Carolina, United States, 27701
    - Velocity Clinical Research - Durham
  - Hickory, North Carolina, United States, 28601
    - Accellacare - Hickory
  - Raleigh, North Carolina, United States, 27609
    - Accellacare - Raleigh
  - Rocky Mount, North Carolina, United States, 27804
    - Accellacare - Rocky Mount
  - Salisbury, North Carolina, United States, 28144
    - Accellacare - Salisbury
  - Statesville, North Carolina, United States, 28625
    - Accellacare - Piedmont Healthcare
  - Wilmington, North Carolina, United States, 28401
    - Accellacare - Tradd Court
  - Winston-Salem, North Carolina, United States, 27103
    - Accellacare - Winston-Salem
  - Winston-Salem, North Carolina, United States, 27157
    - Atrium Health Wake Forest Baptist - Comprehensive Cancer Center
- Ohio
  - Beachwood, Ohio, United States, 44122
    - Velocity Clinical Research - Cleveland (Rapid Medical Research)
  - Cincinnati, Ohio, United States, 45212
    - CTI Clinical Research Center
  - Cincinnati, Ohio, United States, 45242
    - Velocity Clinical Research - Cincinnati (New Horizons Clinical Research - Blue Ash)
- Oklahoma
  - Moore, Oklahoma, United States, 73160
    - Tekton Research - Oklahoma - Magnolia Court
  - Tulsa, Oklahoma, United States, 74137
    - Tekton Research - Delaware Pointe
  - Yukon, Oklahoma, United States, 73099
    - Tekton Research - Oklahoma - Primary Health Partners
- Oregon
  - Grants Pass, Oregon, United States, 97527
    - Velocity Clinical Research - Grants Pass
- Pennsylvania
  - Hatboro, Pennsylvania, United States, 19040
    - Avacare (CCT) - Hatboro Medical Associates
  - Media, Pennsylvania, United States, 19063
    - Atlas Clinical Research - Suburban Research Associates - Media Office
- Rhode Island
  - East Greenwich, Rhode Island, United States, 02818
    - Velocity Clinical Research - Providence (East Greenwich)
- South Carolina
  - Anderson, South Carolina, United States, 29621
    - Velocity Clinical Research - Anderson
  - Charleston, South Carolina, United States, 29414
    - Velocity Clinical Research - Charleston
  - Columbia, South Carolina, United States, 29204
    - Velocity Clinical Research - Columbia (VitaLink)
  - Mt. Pleasant, South Carolina, United States, 29464
    - Accellacare - Charleston
  - Myrtle Beach, South Carolina, United States, 29572
    - Trial Management Associates - Myrtle Beach
  - North Charleston, South Carolina, United States, 29405
    - hyperCORE International - Coastal Carolina Research Center
  - Union, South Carolina, United States, 29379
    - Velocity Clinical Research - Union (Vitalink)
- Tennessee
  - Bristol, Tennessee, United States, 37620
    - Accellacare - PMG Research of Bristol
  - Knoxville, Tennessee, United States, 37909
    - Alliance for Multispecialty Research (AMR) - Corporate
  - Knoxville, Tennessee, United States, 37912
    - Accellacare of Knoxville
- Texas
  - Abilene, Texas, United States, 79606
    - Velocity Clinical Research - Abilene
  - Austin, Texas, United States, 78745
    - Tekton Research - Austin
  - Austin, Texas, United States, 78759
    - Orion Clinical Research
  - Austin, Texas, United States, 78745
    - IMA Clinical Research - Austin
  - Austin, Texas, United States, 78759
    - Velocity Clinical Research - Austin
  - Beaumont, Texas, United States, 77706
    - Tekton Research - Beaumont
  - Brownsville, Texas, United States, 78520
    - PanAmerican Clinical Research - Brownsville, Levee Street
  - Euless, Texas, United States, 76040
    - Cedar Health Research - Arlington/Euless
  - Fort Worth, Texas, United States, 76134
    - EmVenio Research - Fort Worth, TX
  - Fort Worth, Texas, United States, 76135
    - Avacare - Benchmark Research Fort Worth
  - Houston, Texas, United States, 77065
    - DM Clinical Research - Cyfair Clinical Research Center
  - San Antonio, Texas, United States, 78229
    - Tekton Research - Fredericksburg Road
  - Tomball, Texas, United States, 77375
    - DM Clinical Research - Tomball - Multiple Specialties
  - Waco, Texas, United States, 76710
    - Velocity Clinical Research - Waco (formerly: Impact Research Institute)
- Utah
  - Roy, Utah, United States, 84067
    - Avacare (CCT) - Ogden Clinic - Grand View
  - Salt Lake City, Utah, United States, 84117
    - Avacare (CCT) - Olympus Family Medicine
  - South Ogden, Utah, United States, 84405
    - South Ogden Family Medicine
- Virginia
  - Newport News, Virginia, United States, 23606
    - Health Research of Hampton Roads
  - Norfolk, Virginia, United States, 23502
    - AMR - Norfolk (Clinical Research Associates of Tidewater)
  - Suffolk, Virginia, United States, 23435
    - Centricity Research (IACT Health) - Suffolk Primary Care
- Washington
  - Spokane, Washington, United States, 99204
    - Velocity Clinical Research - Medford
  - Spokane, Washington, United States, 99204
    - Velocity Clinical Research - Spokane

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

Adult
Older Adult

Accepts Healthy Volunteers

Description

Inclusion Criteria:

Adults 18 years of age and above, at time of screening.
Completed primary approved/authorized COVID-19 vaccination series with ≥ 2 mRNA vaccine doses.
Last COVID-19 vaccine received ≥6 months prior to study vaccination.
Male and female participants of childbearing potential must agree to consistently use a highly effective method of contraception from at least 30 days prior to enrollment and through 3 months after the study vaccination.
Male participants must refrain from sperm donation from the day of study vaccination through the end of the study. Female participants must refrain from egg donation at least 30 days prior to study vaccination through the end of the study.
Is medically stable, as determined by the site investigator (based on review of health status, vital signs, medical history, and physical examination) with screening lab values within normal limits or abnormalities assessed as not clinically significant. Screening platelet count must be >140,000/μL.
Agree to not participate in any other SARS-CoV-2 infection prevention trial (vaccine, drug, biologic, PrEP) during participation in the study.
Willing and able to provide informed consent prior to initiation of study procedures.
Available for all study visits, willing to participate in all study procedures, and not planning to relocate from the area for the duration of the study.
Negative rapid molecular Covid test at the screening visit and on Day 1 prior to vaccine dosing.

Exclusion Criteria:

Participant has an acute illness as defined by any of the following (note: assessment may be repeated once during screening period) as determined by the site investigator, within 72 hours prior to vaccination as follows:
1. An acute illness that is nearly resolved, with only minor residual symptoms remaining, is allowable if, in the opinion of the site investigator, the residual symptoms will not interfere with the ability of study staff to assess safety parameters as required by the protocol.
2. Presence of a fever ≥ 38.0°C (100.4°F) measured orally at baseline, on Day 1 prior to vaccination.
3. Receipt of antipyretic/analgesic medications within 24 hours prior to vaccine administration.
Participant has had a positive COVID test within 90 days prior to screening.
Current or planned participation in any other interventional clinical trial.
Participation in research involving any investigational product within 45 days prior to study vaccination.
Receipt of any approved or authorized products intended to prevent SARS-CoV2 infection within 6 months prior to study vaccination.
Receipt or donation of blood products or immunoglobulins within 60 days prior to enrollment or planned administration during the study.
Received influenza vaccination within 14 days prior to study vaccination, or any other vaccine within 30 days prior to study vaccination.
Any autoimmune or immunodeficiency disease/condition (including and not limited to untreated or advanced HIV infection with CD4 counts <200 cells/mm^3, history of AIDS defining illness without immune reconstitution, or clinical manifestations of symptomatic HIV, severe combined immunodeficiency (SCID), hypogammaglobulinemia, asplenia or functional asplenia).
Unstable medical or psychiatric illness (acute or chronic illness) requiring significant medical monitoring and intervention during the 90 days prior to enrollment. Note: diabetes mellitus (Types 1 & 2) are not excluded if assessed by the principal investigator (PI) as well-controlled.
Administration of immunosuppressants, systemic glucocorticoids, or other immune-modifying drugs within the following timeframes:
1. B-cell therapies within the 6 months prior to first study vaccination
2. Prednisone, ≥20 mg for more than 2 weeks, within the 30 days prior to study vaccination
3. Other medications in this category, including but not limited to high-dose inhaled corticosteroids (>800 mcg/day of beclomethasone dipropionate or equivalent); antimetabolites; transplant immunosuppressive agents; alkylating agents; cell-depleting agents; or cancer chemotherapeutics, within the 90 days prior to study vaccination.
4. Any medication for any period of time that, in the opinion of the site investigator, could impede immune response to vaccination.
5. Use of any dose montelukast OR inhaled, intranasal, intra-articular, or systemic corticosteroids within 2 weeks prior to study vaccination.
6. Planned use of any of the above medications during the study.
7. Concomitant allergen immunotherapy (AIT) will be allowed only if the participant is stable in the maintenance phase of AIT. Maintenance AIT should not be dosed for at least 7 days before and 7 days after study vaccine dosing, and the PI must document the treating allergist's approval.
Known contraindication to IM injection or blood draws (e.g. bleeding diathesis, acquired coagulopathy, significant bleeding or bruising) or to oral route of administration (unable to swallow tablets).
Any known allergies to components contained in the investigational product or comparator or latex allergy (including polyethylene glycol [PEG] allergies) and/or history of serious reactions to vaccination such as anaphylaxis, respiratory problems, hives, or abdominal pain.
Women who are pregnant (pregnancy tests will be performed at screening and prior to dosing), breastfeeding, or who plan to become pregnant during the study.
History of irritable bowel disease or other inflammatory digestive or gastrointestinal condition that could affect the distribution/safety evaluation of an orally administered vaccine targeting the mucosa of the small intestine. Such conditions may include but are not limited to:
1. Any history of:
  - GI malignancy
  - malabsorption
  - pancreatobiliary disorders
  - inflammatory bowel disease
  - irritable bowel disease
  - hiatal hernia
  - surgical resection
2. History of diagnosis or treatment in past 5 years of:
  - esophageal or gastric motility disorder
  - gastroesophageal reflux disorder
  - peptic ulcer
  - cholecystectomy.
Use of antibiotics, proton pump inhibitors, H2 blockers, or antacids within 7 days prior to study drug administration or planned use from dosing through Day 31.
Use of drugs known to affect gastrointestinal motility including glucagon-like peptide 1 (GLP-1) receptor agonists including tirzepatide (Mounjaro) and semaglutide (Wegovy, Ozempic) within 30 days prior to drug administration.
Daily use of nonsteroidal anti-inflammatory drugs within 7 days prior to study drug administration or planned use during the study.
Personal or familial history of hypercoagulable states to include personal past history of deep vein thrombosis (DVT).
Personal history of myocarditis or pericarditis.
Positive Hepatitis B surface antigen (HBsAg), or hepatitis C virus (HCV) antibody at the screening visit.
History of drug, alcohol, or chemical abuse within 1 year of screening.
Positive urine drug screen for drugs of abuse at screening (except for occasional marijuana use). Concurrent or planned use of marijuana from dosing through Day 31 is prohibited. Positive urine drug screen (UDS) at screening due to prescribed stimulants will be reviewed on a case by case basis.
Cancer, or treatment for cancer, within the past 3 years (excluding fully treated and resolved basal cell carcinoma or squamous cell carcinoma).
History of any form of angioedema.
History of GI bleeding including hematochezia (blood in stool) or melena (black stool) of unknown etiology or that has not been evaluated.
Any history or conditions that may lead to a higher risk of clotting events and/or thrombocytopenia, including:
1. Familial coagulopathy or personal history of bleeding disorder or thrombosis
2. History of heparin-related thrombotic events, and/or receiving heparin treatments
3. History of autoimmune or inflammatory disease
4. Presence of any of the following conditions known to increase the risk of thrombosis within 6 months prior to screening:
  - Recent surgery other than fully healed cesarean delivery or excision/ biopsy of cutaneous lesions
  - Immobility (confined to bed or wheelchair for 3 or more successive days)
  - Head trauma with loss of consciousness or documented brain injury
  - Receipt of anticoagulants for prophylaxis of thrombosis
  - Recent clinically significant infection including hospitalization for COVID-19 related illness.
Any other condition that, in the opinion of the investigator, would pose a health risk to the participant if enrolled or could interfere with evaluation of the investigational product or interpretation of study results.
Study team member or first-degree relative of any study team member (inclusive of sponsor and site personnel involved in the study).

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Primary Purpose: Prevention
Allocation: Randomized
Interventional Model: Sequential Assignment
Masking: Double

Number of Arms

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: VXA-CoV2-3.1 Safety Sentinel Cohort Participants previously immunized against COVID-19 infection will be randomized to receive VXA-CoV2-3.1 (XBB.1.5 vaccine) tablet oral vaccine.	Biological: VXA-CoV2-3.1 Tablets for oral use.
Active Comparator: COMIRNATY® Safety Sentinel Cohort Participants previously immunized against COVID-19 infection will be randomized to receive COMIRNATY® (variant matched vaccine 2023-2024 formula) injectable COVID-19 vaccine.	Biological: COMIRNATY® Intramuscular (IM) injection. Other Names: Pfizer-BioNTech mRNA Vaccine
Experimental: VXA-CoV2-3.3 If no dose-related toxicities are observed, and upon the recommendation of the Data and Safety Monitoring Board following review of Day 31 safety data in the initial safety cohorts (and possibly immunogenicity data), enrollment will continue with the remaining participants who will be randomized to receive a single dose of VXA-CoV2-3.3 (KP.2 vaccine).	Biological: VXA-CoV2-3.3 Tablets for oral use.
Active Comparator: COMIRNATY® If no dose-related toxicities are observed, and upon the recommendation of the Data and Safety Monitoring Board following review of Day 31 safety data in the initial safety cohorts (and possibly immunogenicity data), enrollment will continue with the remaining participants who will be randomized to receive a single dose of 2024-2025 formula of COMIRNATY® mRNA COVID-19 injectable vaccine.	Biological: COMIRNATY® Intramuscular (IM) injection. Other Names: Pfizer-BioNTech mRNA Vaccine

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
KP.2 Cohorts: Percentage of Participants with First Occurrence of Symptomatic Polymerase Chain Reaction (PCR)-Positive COVID-19 at 14 Days Post-vaccination Time Frame: Up to approximately Day 14		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 Time Frame: Up to approximately 12 months		Up to approximately 12 months
XBB Sentinel Cohorts: Percentage of Participants who Experience any Solicited Local Reactogenicity Through 7 Days Post-vaccination Time Frame: Up to approximately Day 7		Up to approximately Day 7
XBB Sentinel Cohorts: Percentage of Participants who Experience any Solicited Systemic Reactogenicity Through 7 Days Post-vaccination Time Frame: Up to approximately Day 7		Up to approximately Day 7
XBB Sentinel Cohorts: Percentage of Participants who Experience Unsolicited Adverse Events (AEs) Through 30 Days Post-vaccination Time Frame: Up to approximately Day 30		Up to approximately Day 30
XBB Sentinel Cohorts: Percentage of Participants who Experience Treatment-emergent Adverse Events (TEAEs) Through 12 Months Post-vaccination Time Frame: Up to approximately 12 months	An AE is any untoward medical occurrence in a clinical study participant irrespective of a causal relationship with the study treatment. TEAEs are any event that occurred after the participant received study treatment. An AE of special interest (AESI) is an AE (serious or non-serious) of scientific and medical concern specific to the sponsor's product or program. Medically attended AEs (MAAEs) are defined as AEs with medically attended visits including hospital, emergency room, urgent care clinic. A serious TEAE (SAE) is any untoward medical occurrence in a clinical study participant after first dose irrespective of a causal relationship with the study treatment that resulted in death, was immediately life threatening, required in-patient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, a congenital anomaly/birth defect, or another medically important serious event.	Up to approximately 12 months
XBB Sentinel Cohorts: Percentage of Participants With any Clinically Significant Abnormal Safety Laboratory Results Within 7 Days Pots-vaccination Time Frame: Up to approximately Day 7		Up to approximately Day 7

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
KP.2 Cohorts: Percentage of Participants with First Occurrence of Symptomatic PCR-Positive COVID-19 Within 14 Days and 12 Months Post-vaccination in Participants with Specified Body Mass Index (BMI) Time Frame: Up to approximately 12 months		Up to approximately 12 months
KP.2 Cohorts: Percentage of Participants with First Occurrence of Symptomatic PCR-Positive COVID-19 within 0 and 6 Months Post-vaccination Time Frame: Up to approximately 6 months		Up to approximately 6 months
KP.2 Cohorts: Percentage of Participants with First Occurrence of Symptomatic PCR-Positive COVID-19 within 6 and 12 Months Post-vaccination Time Frame: Up to approximately 12 months		Up to approximately 12 months
KP.2 Cohorts: Number of Participants with First Occurrence of Asymptomatic PCR-Positive COVID-19 within 14 Days and 12 Months Post-vaccination Time Frame: Up to approximately 12 months		Up to approximately 12 months
KP.2 Cohorts: Number of Participants with First Occurrence of Severe PCR-Positive COVID-19 within 14 Days and 12 Months Post-vaccination Time Frame: Up to approximately 12 months		Up to approximately 12 months
KP.2 Cohorts: Percentage of Participants who Experience any Solicited Local Reactogenicity Through 7 Days Post-vaccination Time Frame: Up to approximately Day 7		Up to approximately Day 7
KP.2 Cohorts: Percentage of Participants who Experience any Solicited Systemic Reactogenicity Through 7 Days Post-vaccination Time Frame: Up to approximately Day 7		Up to approximately Day 7
KP.2 Cohorts: Percentage of Participants who Experience Unsolicited AEs Through 30 Days Post-vaccination Time Frame: Up to approximately Day 30		Up to approximately Day 30
KP.2 Cohorts: Percentage of Participants who Experience TEAEs Through 12 Months Post-vaccination Time Frame: Up to approximately 12 months	An AE is any untoward medical occurrence in a clinical study participant irrespective of a causal relationship with the study treatment. TEAEs are any event that occurred after the participant received study treatment. An AESI is an AE (serious or non-serious) of scientific and medical concern specific to the sponsor's product or program. MAAEs are defined as AEs with medically attended visits including hospital, emergency room, urgent care clinic. An SAE is any untoward medical occurrence in a clinical study participant after first dose irrespective of a causal relationship with the study treatment that resulted in death, was immediately life threatening, required in-patient hospitalization or prolongation of existing hospitalization, resulted in persistent or significant disability/incapacity, a congenital anomaly/birth defect, or another medically important serious event.	Up to approximately 12 months
KP.2 Cohorts: Percentage of Participants With any Clinically Significant Abnormal Safety Laboratory Results Within 7 Days Pots-vaccination Time Frame: Up to approximately Day 7		Up to approximately Day 7
KP.2 Cohorts: Concentration of SARS-CoV-2 Specific Serum Neutralizing Antibodies (nAb) Post-vaccination Time Frame: Day 1 and Months 1, 3, 6, and 12		Day 1 and Months 1, 3, 6, and 12
KP.2 Cohorts: Fold Rise of SARS-CoV-2 Specific Serum nAb Post-vaccination Time Frame: Day 1 and Months 1, 3, 6, and 12		Day 1 and Months 1, 3, 6, and 12
KP.2 Cohorts: Concentration of Serum Immunoglobulin G (IgG) Binding Antibody (bAb) Against Spike Protein (S) and Receptor Binding Domain (RBD) Post-vaccination Time Frame: Day 1 and Months 1, 3, 6, and 12		Day 1 and Months 1, 3, 6, and 12
KP.2 Cohorts: Fold Rise of Serum IgG Anti-S or RBD Specific bAb Post-vaccination Time Frame: Day 1 and Months 1, 3, 6, and 12		Day 1 and Months 1, 3, 6, and 12
KP.2 Cohorts: Concentration of Serum Immunoglobulin A (IgA) bAb Against S and RBD Post-vaccination Time Frame: Day 1 and Months 1, 3, 6, and 12		Day 1 and Months 1, 3, 6, and 12
KP.2 Cohorts: Fold Rise of Serum IgA Anti-S or RBD Specific bAb Post-vaccination Time Frame: Day 1 and Months 1, 3, 6, and 12		Day 1 and Months 1, 3, 6, and 12
KP.2 Cohorts: Concentration of S and RBD-specific Saliva IgA bAb Post-vaccination Time Frame: Day 1 and Months 1, 3, 6, and 12		Day 1 and Months 1, 3, 6, and 12
KP.2 Cohorts: Fold Rise of S and RBD-specific Saliva IgA bAb Post-vaccination Time Frame: Day 1 and Months 1, 3, 6, and 12		Day 1 and Months 1, 3, 6, and 12
KP.2 Cohorts: Concentration of S and RBD-specific Nasal Lining Fluid (NLF) IgA bAb Post-vaccination Time Frame: Day 1 and Months 1, 3, 6, and 12		Day 1 and Months 1, 3, 6, and 12
KP.2 Cohorts: Fold Rise of S and RBD-specific NLF IgA bAb Post-vaccination Time Frame: Day 1 and Months 1, 3, 6, and 12		Day 1 and Months 1, 3, 6, and 12
KP.2 Cohorts: Percentage of Participants With 2, 3, and 4 Fold Rise in S or RBD-Specific Serum IgG and IgA bAb, Serum nAb, Saliva IgA bAb, and NLF IgA bAb Post-vaccination Time Frame: Day 1 and Months 1, 3, 6, and 12		Day 1 and Months 1, 3, 6, and 12
KP.2 Cohorts: Concentration of Intracellular T Cell Cytokine and Cell Surface Marker at Day 1 and 1 Month Post-vaccination Time Frame: Day 1 and Month 1		Day 1 and Month 1
KP.2 Cohorts: Concentration of Intracellular T Cell Cytokine and Cell Surface Marker at 3, 6, and 12 Months Post-vaccination Time Frame: Months 3, 6, and 12		Months 3, 6, and 12

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Vaxart

Investigators

Study Director: James Cummings, MD, Vaxart, Inc.

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

October 8, 2024

Primary Completion (Estimated)

November 1, 2026

Study Completion (Estimated)

November 1, 2026

Study Registration Dates

First Submitted

November 1, 2024

First Submitted That Met QC Criteria

November 1, 2024

First Posted (Actual)

November 4, 2024

Study Record Updates

Last Update Posted (Estimated)

October 22, 2025

Last Update Submitted That Met QC Criteria

October 20, 2025

Last Verified

October 1, 2025

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

VXA-COV-202

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

product manufactured in and exported from the U.S.

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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Study Overview

Status

Conditions

Intervention / Treatment

Study Type

Enrollment (Estimated)

Phase

Contacts and Locations

Study Locations

Participation Criteria

Eligibility Criteria

Ages Eligible for Study

Accepts Healthy Volunteers

Description

Study Plan

How is the study designed?

Design Details

Number of Arms

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

What is the study measuring?

Primary Outcome Measures

Outcome Measure

Measure Description

Time Frame

Secondary Outcome Measures

Outcome Measure

Measure Description

Time Frame

Collaborators and Investigators

Sponsor

Investigators

Study record dates

Study Major Dates

Study Start (Actual)

Primary Completion (Estimated)

Study Completion (Estimated)

Study Registration Dates

First Submitted

First Submitted That Met QC Criteria

First Posted (Actual)

Study Record Updates

Last Update Posted (Estimated)

Last Update Submitted That Met QC Criteria

Last Verified

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Studies a U.S. FDA-regulated device product

product manufactured in and exported from the U.S.

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Clinical Trials on VXA-CoV2-3.1

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