A Study to Evaluate Vaxart's Oral Bivalent GI.1/GII.4 Norovirus Vaccine in Healthy Lactating Females and Their Nursing Infants

A Phase I, Multicenter, Randomized, Double-blind, Placebo-controlled Single Dose, Dose-ranging Study to Evaluate the Safety, Tolerability, and Immunogenicity of Orally Administered Bivalent GI.1/GII.4 Norovirus Vaccine in Healthy Lactating Females ≥ 18 Years Old and Their Breast-feeding Infants

The primary objective of this study is to evaluate the safety and tolerability of an oral bivalent GI.1/GII.4 norovirus vaccine administration in healthy lactating female participants and to assess the short-term immunogenicity of oral bivalent GI.1/GII.4 norovirus vaccine administration in healthy lactating female participants and its association with the immunogenicity response in breastmilk.

Study Overview

• Status: Completed
• Conditions: Norovirus Infections
• Intervention / Treatment: Biological: VXA-G1.1-NN; Biological: VXA-G2.4-NS; Biological: Placebo Tablets

• Study Type: Interventional
• Enrollment (Actual): 76
• Phase: Phase 1

Contacts and Locations

Study Locations

• South Africa
  • Hillbrow, South Africa, 2001
    • WITS RHI Research Centre
  • Honeydew, South Africa, 2040
    • Progress Clinical Research Unit
  • Johannesburg, South Africa, 2001
    • Newtown Clinical Research Centre
  • Kimberley, South Africa, 8301
    • Trident Clinical
  • Vereeniging, South Africa, 1935
    • FCRN Clinical Trials Centre (Pty) Ltd

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

1. Lactating females aged ≥ 18 years at the time of enrolment and their breastfed infants aged >30 days to 11 months of age at the time of the participants' study drug administration.
2. In stable and good general health, without significant medical illness, based on medical history, physical examination (including vital signs), and clinical judgment of the investigator.
3. Lactating females willing and able to provide informed consent which includes compliance with the requirements and restrictions listed in the informed consent form (ICF) and in the protocol.
4. Lactating females who are willing to provide consent for their breastfed infant.
5. Negative pregnancy tests at screening and prior to dose on Day 1.
6. Available for all planned visits and tele-health appointments, and ability to comply with all study-related evaluations (including but not limited to having the ability and willingness to swallow multiple small enteric-coated tablets per study dose, express/pump breastmilk, and collect infant stool samples).
7. Plan to continue breastfeeding as the main source of the infant's nutrition for at least 1 month (longer is preferred with goal of 6 months post dose if possible) from the time of study drug administration. Exclusive breastfeeding is acceptable but not necessary.

8. The nursing infant is the product of a singleton pregnancy AND does not have any of the following:

   1. Any abnormality that may interfere with breastfeeding or milk absorption
   2. Active infection (may be included if the infection resolves and the participant is re-assessed during the screening period)
   3. Infant has any other medical condition or abnormality that, in the opinion of the investigator, could compromise the infant's appropriate inclusion in this study including interference with the interpretation of study results (such as malabsorption)
   4. One or more documented brief resolved unexplained events (BRUEs)
   5. Extreme prematurity (infants who were born at less than 28 weeks gestation)
   6. 30 days of age or less at the participant's study drug administration OR greater than 11 months of age at the participant's study drug administration
   7. Prior hospitalization that is not exclusively for hyperbilirubinemia requiring phototherapy
   8. Any genetic/metabolic disease
   9. Any chronic illness requiring long term medication
9. Participants must be willing to use a highly effective form of contraception for 30 days prior to vaccination and until 60 days after the vaccination. Acceptable forms are oral, implantable, intrauterine, transdermal, intravaginal, injectable, double barrier or abstinence (participants using diaphragms must also use condom). The form of contraception must be approved by the investigator.

Exclusion Criteria:

1. Presence of a fever ≥ 38.0°C measured orally at baseline, on Day 1 prior to vaccination. (Assessment may be repeated once during screening period).
2. Acute disease within 72 hours prior to vaccination, defined as the presence of a moderate or severe illness (as determined by the Investigator through medical history and physical exam). (Assessment may be repeated once during screening period).
3. Participants who have received antipyretic/analgesic medications within 24 hours prior to the intended vaccine administration.
4. Positive human immunodeficiency virus (HIV), Hepatitis B surface antigen (HBsAg), or hepatitis C virus (HCV) tests at the screening visit.
5. History of hypersensitivity or allergic reaction to any component of the investigational vaccine, including but not limited to fish gelatin.
6. History of serious reactions to vaccination such as anaphylaxis, respiratory problems, hives, or abdominal pain.
7. Presence of significant uncontrolled medical or psychiatric illness (acute or chronic) including the institution of new medical/surgical treatment or significant dose alteration for uncontrolled symptoms or drug toxicity within 3 months of screening and reconfirmed at baseline.
8. History of significant pregnancy-related complications during this pregnancy, including but not limited to pre-eclampsia, eclampsia, or gestational diabetes unless a full resolution is documented.
9. Cancer, or treatment for cancer, within the past 3 years (excluding fully treated and resolved basal cell carcinoma or squamous cell carcinoma).
10. Presence of immunosuppression or medical condition possibly associated with impaired immune responsiveness, including diabetes mellitus type 1 or 2.

11. 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:

    a. Any history of:

    i. Malignancy

    ii. Malabsorption

    iii. Pancreatobiliary disorders

    iv. Inflammatory bowel disease

    v. Irritable bowel disease

    vi. Hiatal hernia

    vii. Surgical resection

    b. History of diagnosis or treatment in past 5 years of:

    i. Esophageal or gastric motility disorder

    ii. Gastroesophageal reflux disease (GERD) - Will allow for participants with a history of pregnancy-related GERD if fully resolved for >3 months and no other history of GERD diagnosis

    iii. Peptic ulcer

    iv. Cholecystectomy

12. Any condition that resulted in the absence or removal of the spleen.
13. History of any form of angioedema.
14. Diagnosed bleeding disorder or significant bruising or bleeding difficulties that could make blood draws problematic.
15. History of GI bleeding including hematochezia (blood in stool) or melena (black stool).
16. Any significant hospitalization within the last year which in the opinion of the investigator or sponsor could interfere with study participation.

17. Any of the following history or conditions that may lead to a higher risk of clotting events and/or thrombocytopenia:

    1. Family or personal history of bleeding 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:

    i. Recent surgery other than fully healed cesarean delivery or excision/ biopsy of cutaneous lesions

    ii. Immobility (confined to bed or wheelchair for 3 or more successive days)

    iii. Head trauma with loss of consciousness or documented brain injury

    iv. Receipt of anticoagulants for prophylaxis of thrombosis

    v. Recent clinically significant infection including hospitalization for COVID-19 related illness

18. Any other condition that, in the clinical judgment of the investigator, would jeopardize the safety or rights of a participant taking in the study, would render the participant unable to comply with the protocol, or would interfere with the evaluation of the study endpoints.
19. Receipt of a licensed vaccine (including any COVID-19 vaccines under Emergency Use Authorization) within 14 days prior to study drug dose or planned administration during the study active period.
20. Use of antibiotics, proton pump inhibitors, H2 blockers, or antacids within 7 days prior to study drug administration or planned use during the active study period.
21. Use of medications known to affect the immune function (including but not limited to systemic corticosteroids, leukotriene modifiers, and Janus kinase [JAK] inhibitors) within 2 weeks before study drug administration or planned use during the active study period.
22. Daily use of nonsteroidal anti-inflammatory drugs within 7 days prior to study drug administration or planned use during the active study period.
23. Donation or receipt of blood or blood products within 30 days prior to study drug administration or planned donation during the active study period.
24. Participating in any clinical trial with another investigational product within 30 days prior to the first trial visit or intend to participate in another clinical trial at any time during the conduct of this trial.
25. Are first-degree relatives of individuals involved in trial conduct.
26. Positive urine drug screen for drugs of abuse at screening.
27. Positive alcohol test at screening or baseline.
28. History of drug, alcohol, or chemical abuse within 1 year of screening.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Bivalent GII.4/GI.1 Medium Dose Vaccine; Participants will receive a medium dose of bivalent VXA-G1.1-NN and VXA-GII.4-NS as an oral tablet on Day 1.	Biological: VXA-G1.1-NN; Oral tablets.; Other Names: GI.1; Biological: VXA-G2.4-NS; Oral tablets.; Other Names: GII.4
Experimental: Bivalent GII.4/GI.1 High Dose Vaccine; Participants will receive a high dose of bivalent VXA-G1.1-NN and VXA-GII.4-NS as an oral tablet on Day 1.	Biological: VXA-G1.1-NN; Oral tablets.; Other Names: GI.1; Biological: VXA-G2.4-NS; Oral tablets.; Other Names: GII.4
Placebo Comparator: Placebo; Participants will receive matching placebo orally on Day 1.	Biological: Placebo Tablets; Oral tablets.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Participants (Mothers) With Any Solicited Symptoms of Reactogenicity for 1 Week Following Trial Dose	Solicited symptoms of reactogenicity were predefined adverse events (AEs) for which the participant was specifically questioned, and which were noted by the participant in their solicited symptom diary, including: fever (any temperature 100°F or higher), headache, myalgia (muscle pain), abdominal pain, anorexia (defined as not eating), nausea, vomiting, diarrhea, and malaise/fatigue. The severity of each solicited symptom of reactogenicity was graded by the participant as mild, moderate, severe or life-threatening.	1 week post study dose (8 days)
Number of Participants (Mothers) With Unsolicited Treatment-emergent Adverse Events (TEAEs)	TEAEs:AEs that began after start of an investigational product or an already present event that worsens in intensity or frequency following intervention.An AE considered serious (SAE) if,in view of Investigator or Sponsor,it resulted in death,life-threatening AE,inpatient hospitalization/prolongation of hospitalization,persistent or significant incapacity or disability disrupting normal life functions,congenital anomaly/birth defect,or an important medical event which based upon medical judgment may have jeopardized participant and required intervention to prevent 1 of outcomes.AESIs:serious/non-serious AEs of scientific and medical concern with potential immune mediated conditions and events associated with thrombosis and thrombocytopenia.NOCI:diagnosis post-enrollment and vaccination of new chronic medical condition,including those controllable by medication.An AE was unsolicited if it did not fulfill conditions prelisted in eCRF in terms of diagnosis/onset window post-vaccination.	4 weeks post dose (29 days)
Geometric Mean Concentration (GMC) of Serum Viral Protein 1 (VP1) Specific (G1.1) Immunoglobulin A (IgA) on Days 1, 8 and 29	GMC of serum VP1 specific (G1.1) IgA was measured by Meso Scale Discovery (MSD) assay. Assay was measured in an arbitrary unit per milliliter (AU/mL).	Days 1, 8 and 29
GMC of Serum VP1 Specific (G2.4) IgA on Days 1, 8 and 29	GMC of serum VP1 specific (G2.4) IgA was measured by MSD assay. Assay is measured in AU/mL.	Days 1, 8 and 29
Geometric Mean Fold Rise (GMFR) From Day 1 to Day 8 of Serum VP1 Specific (G1.1) IgA From Day 1 to Day 8	GMFR was measured by MSD assay. The fold rise was calculated per participant by dividing the least square mean value on Day 8 with least square mean value at baseline (Day 1).	Day 1 to Day 8
GMFR of Serum VP1 Specific (G1.1) IgA From Day 1 to Day 29	GMFR was measured by MSD assay. The fold rise was calculated per participant by dividing the least square mean value on Day 29 with least square mean value at baseline (Day 1).	Day 1 to Day 29
GMFR of Serum VP1 Specific (G2.4) IgA From Day 1 to Day 8	GMFR was measured by MSD assay. The fold rise was calculated per participant by dividing the least square mean value on Day 8 with least square mean value at baseline (Day 1).	Day 1 to Day 8
GMFR of Serum VP1 Specific (G2.4) IgA From Day 1 to Day 29	GMFR was measured by MSD assay. The fold rise was calculated per participant by dividing the least square mean value on Day 29 with least square mean value at baseline (Day 1).	Day 1 to Day 29
Number of Participants Who Achieved a 2-fold, 3-fold and 4-fold GMC Rise in Serum VP1 Specific (G1.1) IgA	A 2, 3, 4-fold rise represented the participants with at least a 2, 3, or 4-fold rise in antibodies compared to pre-vaccination dosing Baseline (Day 1).	Days 1, 8, 29 and 180
Number of Participants Who Achieve a 2-fold, 3-fold and 4-fold GMC Rise in Serum VP1 Specific (G2.4) IgA	A 2, 3, 4-fold rise represented the participants with at least a 2, 3, or 4-fold rise in antibodies compared to pre-vaccination dosing Baseline (Day 1).	Days 1, 8, 29 and 180
GMC of Breastmilk VP1 Specific (G1.1) IgA on Days 1, 8 and 29	GMC of breastmilk VP1 specific (G1.1) IgA was measured by MSD assay. Assay is measured in Relative Light Unit per microgram (RLU)/µg of total IgA which is a normalized measure used to quantify the specific binding of IgA antibodies to norovirus VLPs (measured in RLU) relative to the total amount of IgA protein present in a breast milk.	Days 1, 8, and 29
GMC of Breastmilk VP1 Specific (G2.4) IgA on Days 1, 8 and 29	GMC of breastmilk VP1 specific (G2.4) IgA was measured by MSD assay. Assay is measured in RLU/µg of total IgA which is a normalized measure used to quantify the specific binding of IgA antibodies to norovirus VLPs (measured in RLU) relative to the total amount of IgA protein present in a breast milk.	Days 1, 8 and 29
GMFR of Breastmilk VP1 Specific (G1.1) IgA From Day 1 to Day 8	GMFR was measured by MSD assay. The fold rise was calculated per participant by dividing the least square mean value on Day 8 with least square mean value at baseline (Day 1).	Day 1 to Day 8
GMFR of Breastmilk VP1 Specific (G2.4) IgA From Day 1 to Day 8	GMFR was measured by MSD assay. The fold rise was calculated per participant by dividing the least square mean value on Day 8 with least square mean value at baseline (Day 1).	Day 1 to Day 8
GMFR of Breastmilk VP1 Specific (G1.1) IgA From Day 1 to Day 29	GMFR was measured by MSD assay. The fold rise was calculated per participant by dividing the least square mean value on Day 29 with least square mean value at baseline (Day 1).	Day 1 to Day 29
GMFR of Breastmilk VP1 Specific (G2.4) IgA From Day 1 to Day 29	GMFR was measured by MSD assay. The fold rise was calculated per participant by dividing the least square mean value on Day 29 with least square mean value at baseline (Day 1).	Day 1 to Day 29
Number of Participants Who Achieve a 2-fold, 3-fold and 4-fold GMC Rise in Breastmilk VP1 Specific (G1.1) IgA	A 2, 3, and 4-fold rise represented the participants with at least a 2, 3, or 4-fold rise in antibody compared to pre-vaccination dosing Baseline (Day 1).	Days 1, 8, 29, 60 and 180
Number of Participants Who Achieve a 2-fold, 3-fold and 4-fold GMC Rise in Breastmilk VP1 Specific (G2.4) IgA	A 2, 3, and 4-fold rise represented the participants with at least a 2, 3, or 4-fold rise in antibodies compared to pre-vaccination dosing Baseline (Day 1).	Days 1, 8, 29, 60 and 180

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Participants With SAEs, AESIs and NOCIs Through 12 Months Post Dose	An unsolicited AE was an observed AE that did not fulfill the conditions prelisted in the eCRF in terms of diagnosis and/or onset window post-vaccination. An AESIs serious or nonserious) is one of scientific and medical concern specific to the Sponsor's product or program, for which ongoing monitoring and rapid communication by the Investigator to the Sponsor can be appropriate. NOCIs was defined as diagnosis post-enrollment and vaccination of a new medical condition, which is chronic in nature, including those potentially controllable by medication. Only unsolicited SAEs, AESI and NOCIs data was planned to be collected and assessed for the assessment of this OM and solicited SAEs, AESIs and NOCIs was out of the scope of assessment. Participants with unsolicited SAEs, AESIs and NOCIs throughout the trial were reported in this outcome measure.	Up to 12 months
GMC of Serum VP1 Specific (G1.1) IgA on Day 180	GMC of serum VP1 specific (G1.1) IgA was measured by MSD assay. Assay is measured in AU/mL.	Day 180
GMC of Serum VP1 Specific (G2.4) IgA on Day 180	GMC of serum VP1 specific (G2.4) IgA was measured by MSD assay. Assay is measured in AU/mL.	Day 180
GMFR of Serum VP1 Specific (G1.1) IgA From Day 1 to Day 180	GMFR was measured by MSD assay. The fold rise was calculated per participant by dividing the least square mean value on Day 180 with least square mean value at baseline (Day 1).	Day 1 to Day 180
GMFR of Serum VP1 Specific (G2.4) IgA From Day 1 to Day 180	GMFR was measured by MSD assay. The fold rise was calculated per participant by dividing the least square mean value on Day 180 with least square mean value at baseline (Day 1).	Day 1 to Day 180
GMC of Breastmilk VP1 Specific (G1.1) IgA on Days 60 and 180	GMC of breastmilkVP1 specific (G1.1) IgA was measured by MSD assay. Assay is measured in RLU/µg of total IgA which is a normalized measure used to quantify the specific binding of IgA antibodies to norovirus VLPs (measured in RLU) relative to the total amount of IgA protein present in a breast milk.	Days 60 and 180
GMC of Breastmilk VP1 Specific (G2.4) IgA on Days 60 and 180	GMC of breastmilk VP1 specific (G2.4) IgA was measured by MSD assay. Assay is measured in RLU/µg of total IgA which is a normalized measure used to quantify the specific binding of IgA antibodies to norovirus VLPs (measured in RLU) relative to the total amount of IgA protein present in a breast milk.	Days 60 and 180
GMFR of Breastmilk VP1 Specific (G1.1) IgA From Day 1 to Day 60	GMFR was measured by MSD assay. The fold rise was calculated per participant by dividing the least square mean value on Day 60 with least square mean value at baseline (Day 1).	Day 1 to Day 60
GMFR of Breastmilk VP1 Specific (G2.4) IgA From Day 1 to Day 60	GMFR was measured by MSD assay. The fold rise was calculated per participant by dividing the least square mean value on Day 60 with least square mean value at baseline (Day 1).	Day 1 to Day 60
GMFR of Breastmilk VP1 Specific (G1.1) IgA From Day 1 to Day 180	GMFR was measured by MSD assay. The fold rise was calculated per participant by dividing the least square mean value on Day 180 with least square mean value at baseline (Day 1).	Day 1 to Day 180
GMFR of Breastmilk VP1 Specific (G2.4) IgA From Day 1 to Day 180	GMFR was measured by MSD assay. The fold rise was calculated per participant by dividing the least square mean value on Day 180 with least square mean value at baseline (Day 1).	Day 1 to Day 180
GMC of Serum VP1 Specific (G1.1) Immunoglobulin G (IgG) on Days 1, 8, 29, and 180	GMC of serum VP1 specific (G1.1) IgG was measured by MSD assay. Assay is measured in AU/mL.	Days 1, 8, 29, and 180
GMC of Serum VP1 Specific (G2.4) IgG on Days 1, 8, 29, and 180	GMC of serum VP1 specific (G2.4) IgG was measured by MSD assay. Assay is measured in AU/mL.	Days 1, 8, 29 and 180
GMFR of Serum VP1 Specific (G1.1) IgG From Day 1 to Days 8, 29, and 180	GMFR was measured by MSD assay. The fold rise was calculated per participant by dividing the least square mean value on Days 8, 29 and 180 with least square mean value at baseline (Day 1).	From Day 1 to Days 8, 29, and 180
GMFR of Serum VP1 Specific (G2.4) IgG From Day 1 to Days 8, 29, and 180	GMFR was measured by MSD assay. The fold rise was calculated per participant by dividing the least square mean value on Days 8, 29 and 180 with least square mean value at baseline (Day 1).	From Day 1 to Days 8, 29, and 180
Number of Participants Who Achieved a 2-fold, 3-fold, and 4-fold GMC Rise in Serum VP1 Specific (G1.1) IgG	A 2, 3, and 4-fold rise represents the participants with at least a 2, 3, or 4-fold rise in antibodies compared to pre-vaccination dosing Baseline (Day 1).	Days 1, 8, 29, and 180
Number of Participants Who Achieved a 2-fold, 3-fold and 4-fold GMC Rise in Serum VP1 Specific (G2.4) IgG	A 2, 3, and 4-fold rise represented the participants with at least a 2, 3, or 4-fold rise in antibodies compared to pre-vaccination dosing Baseline (Day 1).	Days 1, 8, 29, and 180
Geometric Mean Titer (GMT) of Serum Blocking Titers 50 (BT50) (G1.1) on Days 1, 8, 29, and 180	Serum BT50 (G1.1) through 6 months after trial drug dose was measured by histo-blood group antigen (HBGA) assay. Blood samples were collected at different timepoints throughout the trial.	Days 1, 8, 29, and 180
GMT of Serum BT50 (G2.4) on Days 1, 8, 29, and 180	Serum BT50 (G2.4) through 6 months after trial drug dose was measured by HBGA assay. Blood samples were collected at different timepoints throughout the trial.	Days 1, 8, 29, and 180
GMFR of Serum BT50 (G1.1) From Day 1 to Days 8, 29 and 180	The fold rise was calculated per participant by dividing the least square mean value on Days 8, 29 and 180 with least square mean value at baseline (Day 1).	Day 1 to Days 8, 29, and 180
GMFR of Serum BT50 (G2.4) From Day 1 to Days 8, 29 and 180	The fold rise was calculated per participant by dividing the least square mean value on Days 8, 29 and 180 with least square mean value at baseline (Day 1).	Day 1 to Days 8, 29 and 180
Number of Participants Who Achieved 2-fold, 3-fold, and 4-fold GMT Rise in Serum VP1 Specific (G1.1) IgG	A 2, 3, and 4-fold rise represented the participants with at least a 2, 3, or 4-fold rise in antibodies compared to pre-vaccination dosing Baseline (Day 1).	Days 1, 8, 29, and 180
Number of Participants With 2-fold, 3-fold and 4-fold GMT Rise in Serum VP1 Specific IgG (G2.4)	A 2, 3, and 4-fold rise represented the participants with at least a 2, 3, or 4-fold rise in antibodies compared to pre-vaccination dosing Baseline (Day 1).	Days 1, 8, 29, and 180

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
GMC of Nasal VP1 Specific (G1.1) IgA	GMC of nasal VP1 specific (G1.1) IgA from lactating mothers was measured by MSD assay. Assay is measured in microgram per milligram (µg/mg).	Days 1, 8, 29, 60, and 180
GMC of Nasal VP1 Specific (G2.4) IgA	GMC of nasal VP1 specific (G2.4) IgA from lactating mothers was measured by MSD assay. Assay is measured in µg/mg.	Days 1, 8, 29, 60, and 180
GMFR of Nasal VP1 Specific (GI.I) IgA From Day 1 to Days 8, 29, 60 and 180	GMFR was measured by MSD assay. The fold rise was calculated per participant by dividing the least square mean value on Days 8, 29 and 180 with least square mean value at baseline (Day 1).	Day 1 to Days 8, 29, 60 and 180
GMFR of Nasal VP1 Specific (G2.4) IgA From Day 1 to Days 8, 29, 60 and 180	GMFR was measured by MSD assay. The fold rise was calculated per participant by dividing the least square mean value on Days 8, 29 and 180 with least square mean value at baseline (Day 1).	Day 1 to Days 8, 29, 60 and 180
Number of Participants With 2-fold, 3-fold and 4-fold GMC Rise in Nasal VP1 Specific IgA (G1.1)	A 2, 3, and 4-fold rise represented the participants with at least a 2, 3, or 4-fold rise in antibodies compared to pre-vaccination dosing Baseline (Day 1).	Days 1, 8, 29, 60 and 180
Number of Participants With 2-fold, 3-fold and 4-fold GMC Rise in Nasal VP1 Specific IgA (G2.4)	A 2, 3, and 4-fold rise represented the participants with at least a 2, 3, or 4-fold rise in antibodies compared to pre-vaccination dosing Baseline (Day 1).	Days 1, 8, 29, 60 and 180
GMC of Saliva VP1 Specific (G1.1) IgA	GMC of saliva VP1 specific (G1.1) IgA from lactating mothers was measured by MSD assay. Assay is measured in µg/mg.	Days 1, 8, 29, 60, and 180
GMC of Saliva VP1 Specific (G2.4) IgA	GMC of saliva VP1 specific (G2.4) IgA from lactating mothers was measured by MSD assay. Assay is measured in µg/mg.	Days 1, 8, 29, 60, and 180
GMFR of Saliva VP1 Specific (G1.1) IgA From Day 1 to Days 8, 29, 60 and 180	GMFR was measured by MSD assay. The fold rise was calculated per participant by dividing the least square mean value on Days 8, 29 and 180 with least square mean value at baseline (Day 1).	Day 1 to Days 8, 29, 60, and 180
GMFR of Saliva VP1 Specific (G2.4) IgA From Day 1 to Days 8, 29, 60, and 180	GMFR was measured by MSD assay. The fold rise was calculated per participant by dividing the least square mean value on Days 8, 29 and 180 with least square mean value at baseline (Day 1).	From Day 1 to Days 8, 29, 60, and 180
Number of Participants With 2-fold, 3-fold and 4-fold GMC Rise in Saliva VP1 Specific IgA (G1.1)	A 2, 3, and 4-fold rise represented the participants with at least a 2, 3, or 4-fold rise in antibodies compared to pre-vaccination dosing Baseline (Day 1).	Days 1, 8, 29, 60 and 180
Number of Participants With 2-fold, 3-fold and 4-fold GMC Rise in Saliva VP1 Specific IgA (G2.4)	A 2, 3, and 4-fold rise represented the participants with at least a 2, 3, or 4-fold rise in antibodies compared to pre-vaccination dosing Baseline (Day 1).	Days 1, 8, 29, 60 and 180
GMC of Infant Stool VP1 Specific (G1.1) IgA	GMC of infant stool VP1 specific (G1.1) IgA was measured by Enzyme-linked immunosorbent assay (ELISA). Assay is measured in mg/gm.	Days 1, 29 and 60
GMC of Infant Stool VP1 Specific (G2.4) IgA	GMC of infant stool VP1 specific (G2.4) IgA was measured by ELISA. Assay is measured in mg/gm.	Days 1, 29 and 60
GMFR of Infant Stool VP1 Specific (G1.1) IgA From Day 1 to Days 29 and 60	GMFR was measured by ELISA. The fold rise was calculated per participant (infant) by dividing the least square mean value on Days 8, 29 and 180 with least square mean value at baseline (Day 1).	Day 1 to Days 29 and 60
GMFR of Infant Stool VP1 Specific (G2.4) IgA From Day 1 to Days 29 and 60	GMFR was measured by ELISA. The fold rise was calculated per infant (participant) by dividing the least square mean value on Days 8, 29 and 180 with least square mean value at baseline (Day 1).	Day 1 to Days 29 and 60
Number of Infants With 2-fold, 3-fold and 4-fold GMC Rise in Infant Stool VP1 Specific IgA (G1.1)	A 2, 3 and 4-fold rise represented the participants (infants) with at least a 2, 3 or 4-fold rise in antibodies compared to pre-vaccination dosing Baseline (Day 1).	Days 1, 29 and 60
Number of Infants With 2-fold, 3-fold and 4-fold GMC Rise in Infant Stool VP1 Specific IgA (G2.4)	A 2, 3 and 4-fold rise represented the participants (infants) with at least a 2, 3 or 4-fold rise in antibodies compared to pre-vaccination dosing Baseline (Day 1).	Days 1, 8, 29 and 60
Number of Participants With Norovirus Acute Gastroenteritis	Data was not collected for this outcome measure.	From first dose up to Day 365

Collaborators and Investigators

• Sponsor: Vaxart
• Investigators: Study Director: Medical Director, Vaxart, Inc.

Study record dates

Study Major Dates

• Study Start (Actual): October 27, 2023
• Primary Completion (Actual): December 13, 2024
• Study Completion (Actual): December 13, 2024

Study Registration Dates

• First Submitted: November 19, 2025
• First Submitted That Met QC Criteria: November 19, 2025
• First Posted (Actual): November 28, 2025

Study Record Updates

• Last Update Posted (Actual): April 15, 2026
• Last Update Submitted That Met QC Criteria: March 25, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: Healthy participants; VXA-G1.1-NN; VXA-G2.4-NS
• Additional Relevant MeSH Terms: Infections; RNA Virus Infections; Virus Diseases; Caliciviridae Infections
• Other Study ID Numbers: VXA-NVV-108

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No