COVID-19Phase 3COVID-19NCT05973006
Phase 3 Adolescent Study for SARS-CoV-2 rS Variant Vaccines
A Phase 3 study testing NVX-CoV2601 co-formulated Omicron XBB.1.5 SARS-CoV-2 rS vaccine and Prototype/XBB.1.5 Bivalent Vaccine (5 µg) in people with COVID-19, run by Novavax at 20 sites in United States.
Trial summary
This study is a large-scale investigation (Phase 3) into a new booster shot designed specifically for teenagers. The booster targets a particular variant of COVID-19, Omicron XBB.1.5. Read more about this study
- Who is it for?
- Ages 11 to 18 yearsHealthy volunteers can take part
- Conditions the study is for
- COVID-19
- What is being tested?
- NVX-CoV2601 co-formulated Omicron XBB.1.5 SARS-CoV-2 rS vaccine and Prototype/XBB.1.5 Bivalent Vaccine (5 µg)
- Type of treatment
- Vaccines, Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 400 participants
- Where
- 20 sitesUnited States
- Study dates
- 16 Aug 2023to 30 Sep 2024
- Phase
- Phase 3
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 11 to 18 years
- All sexes
- Healthy volunteers accepted
- Child, Adult
Who may be able to join
- Adolescents ≥ 12 to < 18 years of age at screening
- Participant and parent(s)/caregiver(s) or legally acceptable representative willing and able to give in-formed consent and assent, as required, prior to study enrollment and to comply with study procedures.
- Participants of childbearing potential (defined as any participant who has experienced menarche and who is NOT surgically sterile [ie, hysterectomy, bilateral tubal ligation, or bilateral oophorectomy] or post-menopausal [defined as amenorrhea ≥ 12 consecutive months]) must agree to be heterosexually inactive from at least 28 days prior to enrollment and through the end of the study OR agree to consistently use a medically acceptable method of contraception listed below from ≥ 28 days prior to enrollment and through the end of the study.
- Is medically stable, as determined by the investigator (based on review of health status, vital signs [to include body temperature], medical history, and targeted physical examination [to include body weight]). Vital signs must be within medically acceptable ranges prior to the vaccination.
- Agrees to not participate in any other SARS-CoV-2 prevention or treatment trials for the duration of the study.
- Have previously received ≥ 2 doses of the Moderna and/or Pfizer-BioNTech monovalent and/or bivalent COVID-19 vaccines with the last dose having been given ≥ 90 days previously prior to study vaccination.
Who cannot join
- Received COVID-19 vaccines other than Moderna and/or Pfizer-BioNTech in the past, inclusive of clinical trial COVID-19 vaccines.
- Participation in research involving receipt of investigational products (drug/biologic/device) within 90 days prior to study vaccination.
- Received influenza vaccination within 14 days prior to study vaccination.
- Received any vaccine ≤ 45 days prior to study vaccination, except for rabies, human papilloma virus (HPV), tetanus-diphtheria (Td), tetanus, diphtheria, and pertussis (TDaP/DTap), hepatitis B virus (HBV), and meningococcal vaccines which may be given as medically indicated.
- Any known allergies to products contained in the investigational product.
- Any history of anaphylaxis to any prior vaccine.
Show all 19Show fewer
- Autoimmune or immunodeficiency disease/condition (iatrogenic or congenital) requiring ongoing immunomodulatory therapy.
- Chronic administration (defined as > 14 continuous days) of immunosuppressant, systemic glucocorticoids, or other immune-modifying drugs within 90 days prior to study vaccination.
- An immunosuppressant dose of glucocorticoid is defined as a systemic dose ≥ 10 mg of prednisone per day or equivalent. The use of topical or intranasal glucocorticoids is permitted. Topical tacrolimus and ocular cyclosporin are permitted.
- Received immunoglobulin, blood-derived products, or immunosuppressant drugs within 90 days prior to study vaccination, except for rabies immunoglobulin which may be given if medically indicated.
- Active cancer (malignancy) on therapy within 3 years prior to study vaccination (with the exception of adequately treated non-melanomatous skin carcinoma or lentigo maligna and uterine cervical carcinoma in situ without evidence of disease, at the discretion of the investigator).
- Participants who are breastfeeding, pregnant, or who plan to become pregnant prior to the end of study.
- Suspected or known history of alcohol abuse or drug addiction within 2 years prior to the study vaccine dose that, in the opinion of the investigator, might interfere with protocol compliance.
- 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 study vaccine or interpretation of study results (including neurologic or psychiatric conditions likely to impair the quality of safety reporting).
- Study team member or immediate family member of any study team member (inclusive of Sponsor, clinical research organization [CRO], and study site personnel involved in the conduct or planning of the study).
- Participants with a history of myocarditis or pericarditis.
- Respiratory symptoms in the past 3 days (ie, cough, sore throat, difficulty breathing).
- Temperature of > 38°C within 24 hours of planned study vaccination (site measured or participant measured).
- Blood pressure of ≥ 160/100 mmHg.
Trial locations and contacts
20 sites in 1 country.
20 sites in 1 country
United States20 sites
Benchmark Research
Austin, Texas, 78705
Velocity Clinical Research
Cincinnati, Ohio, 45246
South Texas Clinical Research
Corpus Christi, Texas, 78404
Alfa Medical Research
Davie, Florida, 33024
DM Clinical Research
Houston, Texas, 77065
Westside Center for Clinical Research
Jacksonville, Florida, 32205
Medical Colleagues of Texas, LLP
Katy, Texas, 77450
Velocity Clinical Research
Lafayette, Louisiana, 70508
Johnson County Clinical Trials
Lenexa, Kansas, 66219
Velocity Clinical Research
Meridian, Idaho, 83642
ITB Research
Miami, Florida, 33173
Clinical Research Associates, Inc
Nashville, Tennessee, 37203
Alliance for Multispecialty Research, LLC (AMR)
Newton, Kansas, 67114
Research Your Health
Plano, Texas, 75093
Mountain View CCT Research
Pleasant View, Utah, 84404
DM Clinical Research - Chicago
River Forest, Illinois, 60305
Tekton Research
San Antonio, Texas, 78244
Tekton Research
Tulsa, Oklahoma, 74137
Velocity Clinical Research
Vestal, New York, 13850
AMR
Wichita, Kansas, 67207
About this study
Official title: A Phase 3, Randomized, Double-Blinded Study to Evaluate the Safety and Immunogenicity of Omicron Subvariant and Bivalent SARS-CoV-2 rS Vaccines in Adolescents Previously Vaccinated With mRNA COVID-19 Vaccines
This study is a large-scale investigation (Phase 3) into a new booster shot designed specifically for teenagers. The booster targets a particular variant of COVID-19, Omicron XBB.1.5. The main focus is on safety: researchers want to see if this new booster is safe for teenagers who have already received two doses of the Pfizer or Moderna mRNA COVID-19 vaccines. To ensure a fair comparison, the study will use a double-blind approach. This means two groups of teenagers will receive booster shots, but neither the teenagers nor the researchers giving the shots will know beforehand which version of the booster each person gets. The study will also assess how well the body fights the virus after the booster shot.
Read the detailed description
This is a Phase 3, randomized, double-blinded study to evaluate the safety and immunogenicity of booster doses of Omicron subvariant severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) recombinant (r) spike (S) protein nanoparticle vaccines (SARS-CoV-2 rS) adjuvanted with Matrix-M™ adjuvant (NVX-CoV2601 [Omicron XBB.1.5]) and bivalent (NVX-CoV2373 [prototype] + NVX CoV2601) in previously vaccinated adolescent participants ≥ 12 to < 18 years of age.
Approximately 400 adolescents who have received a regimen of ≥ 2 doses of the Moderna and/or Pfizer-BioNTech monovalent and/or bivalent COVID-19 vaccines ≥ 90 days previously will be randomized 1:1 to Group A or Group B:
- Group A: 1 dose of NVX-CoV2601 (1 on Day 0)
- Group B: 1 dose of bivalent NVX-CoV2373 + NVX-CoV2601 (1 on Day 0) All participants will remain on study for immunogenicity and safety data collection through Day 180.
- Conditions
- COVID-19
- Being tested
- NVX-CoV2601 co-formulated Omicron XBB.1.5 SARS-CoV-2 rS vaccine, Prototype/XBB.1.5 Bivalent Vaccine (5 µg)
- Medical subject headings
- COVID-19
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
NVX-CoV2601 co-formulated Omicron XBB.1.5 SARS-CoV-2 rS vaccineBiological
Also called NVX-CoV2601
Coformulated Omicron XBB.1.5 SARS-CoV-2 rS vaccine with Matrix-M adjuvant: supplied as a solution for preparation for injection, at a concentration of 10 µg antigen and 100 µg adjuvant per mL. All injections will be administered in a 0.5 mL injection volume at a dose of 5 µg antigen with 50 µg Matrix-M adjuvant.
Prototype/XBB.1.5 Bivalent Vaccine (5 µg)Biological
Also called Omicron XBB.1.5 (sub-variant)SARS-CoV-2 rS /Matrix-M Adjuvant
A site-mixed bivalent vaccine prepared by combining 0.25 mL of NVX-CoV2373 and 0.25 mL NVX-CoV2601. All injections will be administered in a 0.5 mL injection volume at a dose of 5 µg total antigen (2.5 µg prototype antigen + 2.5 µg Omicron XBB.1.5 antigen) with 50 µg Matrix-M adjuvant.
| Study group | Role | What they receive |
|---|---|---|
| Group-A NVX-CoV2601 | Experimental | The Monovalent NVX-CoV2601 of 5 μg of antigen with 50 μg of Matrix-M adjuvant Receives: Biological: NVX-CoV2601 co-formulated Omicron XBB.1.5 SARS-CoV-2 rS vaccine |
| Group-B Bivalent NVX CoV2373 + NVX CoV2601 | Active comparator | The Bivalent NVX CoV2373 + NVX CoV2601 of 5 μg of each antigen with a total of 50 μg of Matrix-M adjuvant Receives: Biological: Prototype/XBB.1.5 Bivalent Vaccine (5 µg) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Participants With Solicited Local and Systemic AEs for 7 Days Following Vaccination
Participants with solicited local and systemic adverse events (AEs) To assess the overall safety of 1 heterologous booster dose of NVX CoV2601 and the bivalent vaccine (NVX CoV2373 + NVX-CoV2601) for 7 days following vaccination
Measured: Day 7
Participants With Unsolicited AEs Through 28 Days After Vaccination
Participants with unsolicited AEs to assess the overall safety of 1 heterologous booster dose of NVX CoV2601 and the bivalent vaccine (NVX CoV2373 + NVX-CoV2601) through 28 days after vaccination.
Measured: Day 28
Participants With (MAAEs) Attributed to Study Vaccine, (AESIs) (PIMMCs), Myocarditis and/or Pericarditis, and Complications Specific to COVID-19), and Serious Adverse Events (SAEs)
Participants with medically attended adverse events (MAAEs) attributed to study vaccine, adverse events of special interest (AESIs) (predefined list including potential immune-mediated medical conditions (PIMMCs), myocarditis and/or pericarditis, and complications specific to COVID-19), and serious adverse events (SAEs) o assess the overall safety of 1 heterologous booster dose of NVX CoV2601 and the bivalent vaccine (NVX CoV2373 + NVX-CoV2601)through day 180 or end of study (EOS).
Measured: Day 180
Immunogenicity Index- Neutralizing Antibody (NAb) Expressed as Geometric Mean Titers (GMTs) to the Omicron XBB.1.5 Strain.
The neutralizing antibody (NAb) response induced by NVX CoV2601 and the bivalent vaccine (NVX CoV2373 + NVX-CoV2601) against the Omicron XBB.1.5 strain assessed at Day 28 following initial study vaccination.
Measured: Day 0 and Day 28
Immunogenicity Index- The Neutralizing Antibody (NAb) Expressed as Geometric Mean Fold Rise (GMFR) to the Omicron XBB.1.5 Strain.
the neutralizing antibody (NAb) response induced by NVX CoV2601 and the bivalent vaccine (NVX CoV2373 + NVX-CoV2601) against the Omicron XBB.1.5 strain, assessed at Day 28
Measured: Day 28
Secondary outcomes (5)
Neutralizing Antibody (NAb) Expressed as Geometric Mean Titers (GMTs) to the Omicron XBB.1.5 Strain.
the neutralizing antibody NAb response induced by NVX CoV2601 and the bivalent vaccine (NVX CoV2373 + NVX-CoV2601) against the Omicron XBB.1.5 strain over time. at relevant time points.
Measured: Day 0 to Day 180
Neutralizing Antibody (NAb) Expressed as Geometric Mean Fold Rise (GMFR) to the Omicron XBB.1.5 Strain.
The neutralizing antibody NAb response induced by NVX CoV2601 and the bivalent vaccine (NVX CoV2373 + NVX-CoV2601) against the Omicron XBB.1.5 strain over time. at relevant time points.
Measured: Day 28 to Day 180
IgG Geometric Mean ELISA (Enzyme-linked Immunosorbent Assay) Units (GMEUs) to the Omicron XBB.1.5 S Protein.
The immunoglobulin G (IgG) antibody levels induced by NVX CoV2601 and the bivalent vaccine (NVX CoV2373 + NVX-CoV2601) against the Omicron XBB.1.5 strain over time.at relevant time points.
Measured: Day 0 to Day 180
NAb(Neutralizing Antibody Titers) Levels Are Measured to the Ancestral (Wuhan) Strain .
The NAb antibody responses induced by NVX CoV2601 and the bivalent vaccine (NVX CoV2373 + NVX-CoV2601) against the ancestral (Wuhan) strain at relevant time points .
Measured: Day 0 to 180
Serum IgG GMEUs Levels Are Measured to the Ancestral (Wuhan) Strain .
The serum IgG antibody responses induced by NVX CoV2601 and the bivalent vaccine (NVX CoV2373 + NVX-CoV2601) against the ancestral (Wuhan) strain at relevant time points.
Measured: Day 0 to Day 180
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted2 Aug 2023
- Study start16 Aug 2023
- Primary completion1 Apr 2024
- Study completion30 Sep 2024
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for COVID-19Studies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 3
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 400 participants (actual)
Sponsor and investigators
- Lead sponsor
- Novavax
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Clinical Development, Study director, Novavax
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05973006
- Sponsor's protocol ID
- 2019nCoV-314
- Acronym
- COVID-19
- Status last verified
- Jun 2025
- First submitted
- 31 Jul 2023
- Last updated
- 15 Jul 2025
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Publications
Zhu M, Massuda E, Patel U, Chau G, Kalkeri R, Cloney-Clark S, Smith K, Neal S, Plested JS, Mallory RM, Bennett C. Detection of Anti-SARS-CoV-2 Mucosal Immunoglobulin A in Clinical Saliva Samples After a Dose of Novavax COVID-19 Vaccine. J Med Virol. 2025 Oct;97(10):e70645. doi: 10.1002/jmv.70645.
PubMed 41117170
Study at a glance
From the registry record, last updated by the sponsor on 15 Jul 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Phase 3, Randomized, Double-Blinded Study to Evaluate the Safety and Immunogenicity of Omicron Subvariant and Bivalent SARS-CoV-2 rS Vaccines in Adolescents Previously Vaccinated With mRNA COVID-19 Vaccines
- ClinicalTrials.gov ID
- NCT05973006
- Acronym / sponsor ID
- COVID-19 / 2019nCoV-314
- Conditions
- COVID-19
- Phase
- Phase 3
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 400 participants (actual)
- Lead sponsor
- NovavaxIndustry (pharma, biotech, devices)
- Study start
- 16 Aug 2023 (actual)
- Primary completion
- 1 Apr 2024 (actual)
- Study completion
- 30 Sep 2024 (actual)
- First posted
- 2 Aug 2023 (actual)
- Results
- Posted 15 Jul 2025
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study is a large-scale investigation (Phase 3) into a new booster shot designed specifically for teenagers. The booster targets a particular variant of COVID-19, Omicron XBB.1.5. The main focus is on safety: researchers want to see if this new booster is safe for teenagers who have already received two doses of the Pfizer or Moderna mRNA COVID-19 vaccines. To ensure a fair comparison, the study will use a double-blind approach. This means two groups of teenagers will receive booster shots, but neither the teenagers nor the researchers giving the shots will know beforehand which version of the booster each person gets. The study will also assess how well the body fights the virus after the booster shot.
Detailed description
This is a Phase 3, randomized, double-blinded study to evaluate the safety and immunogenicity of booster doses of Omicron subvariant severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) recombinant (r) spike (S) protein nanoparticle vaccines (SARS-CoV-2 rS) adjuvanted with Matrix-M™ adjuvant (NVX-CoV2601 [Omicron XBB.1.5]) and bivalent (NVX-CoV2373 [prototype] + NVX CoV2601) in previously vaccinated adolescent participants ≥ 12 to < 18 years of age.
Approximately 400 adolescents who have received a regimen of ≥ 2 doses of the Moderna and/or Pfizer-BioNTech monovalent and/or bivalent COVID-19 vaccines ≥ 90 days previously will be randomized 1:1 to Group A or Group B:
- Group A: 1 dose of NVX-CoV2601 (1 on Day 0)
- Group B: 1 dose of bivalent NVX-CoV2373 + NVX-CoV2601 (1 on Day 0) All participants will remain on study for immunogenicity and safety data collection through Day 180.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, investigator)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Group-A NVX-CoV2601 | Experimental | Biological: NVX-CoV2601 co-formulated Omicron XBB.1.5 SARS-CoV-2 rS vaccineThe Monovalent NVX-CoV2601 of 5 μg of antigen with 50 μg of Matrix-M adjuvant |
| Group-B Bivalent NVX CoV2373 + NVX CoV2601 | Active comparator | Biological: Prototype/XBB.1.5 Bivalent Vaccine (5 µg)The Bivalent NVX CoV2373 + NVX CoV2601 of 5 μg of each antigen with a total of 50 μg of Matrix-M adjuvant |
Who may qualify
- Ages
- 11 to 18 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Child, Adult
Key inclusion criteria (6 listed)
- Adolescents ≥ 12 to < 18 years of age at screening
- Participant and parent(s)/caregiver(s) or legally acceptable representative willing and able to give in-formed consent and assent, as required, prior to study enrollment and to comply with study procedures.
- Participants of childbearing potential (defined as any participant who has experienced menarche and who is NOT surgically sterile [ie, hysterectomy, bilateral tubal ligation, or bilateral oophorectomy] or post-menopausal [defined as amenorrhea ≥ 12 consecutive months]) must agree to be heterosexually inactive from at least 28 days prior to enrollment and through the end of the study OR agree to consistently use a medically acceptable method of contraception listed below from ≥ 28 days prior to enrollment and through the end of the study.
- Is medically stable, as determined by the investigator (based on review of health status, vital signs [to include body temperature], medical history, and targeted physical examination [to include body weight]). Vital signs must be within medically acceptable ranges prior to the vaccination.
- Agrees to not participate in any other SARS-CoV-2 prevention or treatment trials for the duration of the study.
Key exclusion criteria (19 listed)
- Received COVID-19 vaccines other than Moderna and/or Pfizer-BioNTech in the past, inclusive of clinical trial COVID-19 vaccines.
- Participation in research involving receipt of investigational products (drug/biologic/device) within 90 days prior to study vaccination.
- Received influenza vaccination within 14 days prior to study vaccination.
- Received any vaccine ≤ 45 days prior to study vaccination, except for rabies, human papilloma virus (HPV), tetanus-diphtheria (Td), tetanus, diphtheria, and pertussis (TDaP/DTap), hepatitis B virus (HBV), and meningococcal vaccines which may be given as medically indicated.
- Any known allergies to products contained in the investigational product.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| NVX-CoV2601 co-formulated Omicron XBB.1.5 SARS-CoV-2 rS vaccineAlso: NVX-CoV2601Coformulated Omicron XBB.1.5 SARS-CoV-2 rS vaccine with Matrix-M adjuvant: supplied as a solution for preparation for injection, at a concentration of 10 µg antigen and 100 µg adjuvant per mL. All injections will be administered in a 0.5 mL injection volume at a dose of 5 µg antigen with 50 µg Matrix-M adjuvant. | Biological | Group-A NVX-CoV2601 |
| Prototype/XBB.1.5 Bivalent Vaccine (5 µg)Also: Omicron XBB.1.5 (sub-variant)SARS-CoV-2 rS /Matrix-M AdjuvantA site-mixed bivalent vaccine prepared by combining 0.25 mL of NVX-CoV2373 and 0.25 mL NVX-CoV2601. All injections will be administered in a 0.5 mL injection volume at a dose of 5 µg total antigen (2.5 µg prototype antigen + 2.5 µg Omicron XBB.1.5 antigen) with 50 µg Matrix-M adjuvant. | Biological | Group-B Bivalent NVX CoV2373 + NVX CoV2601 |
Primary outcome
Participants With Solicited Local and Systemic AEs for 7 Days Following Vaccination
Time frame: Day 7
Participants with solicited local and systemic adverse events (AEs) To assess the overall safety of 1 heterologous booster dose of NVX CoV2601 and the bivalent vaccine (NVX CoV2373 + NVX-CoV2601) for 7 days following vaccination
Participants With Unsolicited AEs Through 28 Days After Vaccination
Time frame: Day 28
Participants with unsolicited AEs to assess the overall safety of 1 heterologous booster dose of NVX CoV2601 and the bivalent vaccine (NVX CoV2373 + NVX-CoV2601) through 28 days after vaccination.
Participants With (MAAEs) Attributed to Study Vaccine, (AESIs) (PIMMCs), Myocarditis and/or Pericarditis, and Complications Specific to COVID-19), and Serious Adverse Events (SAEs)
Time frame: Day 180
Participants with medically attended adverse events (MAAEs) attributed to study vaccine, adverse events of special interest (AESIs) (predefined list including potential immune-mediated medical conditions (PIMMCs), myocarditis and/or pericarditis, and complications specific to COVID-19), and serious adverse events (SAEs) o assess the overall safety of 1 heterologous booster dose of NVX CoV2601 and the bivalent vaccine (NVX CoV2373 + NVX-CoV2601)through day 180 or end of study (EOS).
Immunogenicity Index- Neutralizing Antibody (NAb) Expressed as Geometric Mean Titers (GMTs) to the Omicron XBB.1.5 Strain.
Time frame: Day 0 and Day 28
The neutralizing antibody (NAb) response induced by NVX CoV2601 and the bivalent vaccine (NVX CoV2373 + NVX-CoV2601) against the Omicron XBB.1.5 strain assessed at Day 28 following initial study vaccination.
Immunogenicity Index- The Neutralizing Antibody (NAb) Expressed as Geometric Mean Fold Rise (GMFR) to the Omicron XBB.1.5 Strain.
Time frame: Day 28
the neutralizing antibody (NAb) response induced by NVX CoV2601 and the bivalent vaccine (NVX CoV2373 + NVX-CoV2601) against the Omicron XBB.1.5 strain, assessed at Day 28
5 secondary outcomes
Neutralizing Antibody (NAb) Expressed as Geometric Mean Titers (GMTs) to the Omicron XBB.1.5 Strain.
Time frame: Day 0 to Day 180
Neutralizing Antibody (NAb) Expressed as Geometric Mean Fold Rise (GMFR) to the Omicron XBB.1.5 Strain.
Time frame: Day 28 to Day 180
IgG Geometric Mean ELISA (Enzyme-linked Immunosorbent Assay) Units (GMEUs) to the Omicron XBB.1.5 S Protein.
Time frame: Day 0 to Day 180
NAb(Neutralizing Antibody Titers) Levels Are Measured to the Ancestral (Wuhan) Strain .
Time frame: Day 0 to 180
Serum IgG GMEUs Levels Are Measured to the Ancestral (Wuhan) Strain .
Time frame: Day 0 to Day 180
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 15 Jul 2025.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Derived from this study: PubMed 41117170Zhu M, Massuda E, Patel U, Chau G, Kalkeri R, Cloney-Clark S, Smith K, Neal S, Plested JS, Mallory RM, Bennett C. Detection of Anti-SARS-CoV-2 Mucosal Immunoglobulin A in Clinical Saliva Samples After a Dose of Novavax COVID-19 Vaccine. J Med Virol. 2025 Oct;97(10):e70645. doi: 10.1002/jmv.70645.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Clinical Development study director
Novavax
20 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 3 study testing NVX-CoV2601 co-formulated Omicron XBB.1.5 SARS-CoV-2 rS vaccine and Prototype/XBB.1.5 Bivalent Vaccine (5 µg) in people with COVID-19, run by Novavax at 20 sites in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 19 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 15 Jul 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 20 sites in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
Yes. Results are posted in the registry (first posted 15 Jul 2025). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Participants With Solicited Local and Systemic AEs for 7 Days Following Vaccination (time frame: Day 7). The study lists 5 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT05973006, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 15 Jul 2025; AzTrials last refreshed its copy on 28 Oct 2026.