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> Record changed: 2026-10-13

# A Study to Evaluate the Immunogenicity and Safety of Two Recombinant Protein COVID-19 Vaccines in Population Aged ≥18 Years as Booster Vaccines

NCT05323461

Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05323461)

Phase

Phase 3

Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05323461)

Recruitment status

Unknown

Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05323461)

Participants

1,800

Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05323461)

Lead sponsor

Sinocelltech Ltd.

Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05323461)

Start date

2022-05-30

Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05323461)

Number of sites

1

Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05323461)

## Title and summary

**Summary**

The study is a randomized, double-blind, and positive-controlled Phase III booster study. It will evaluate the immunogenicity and safety of one dose of SCTV01C or SCTV01E as booster compared with either one dose of Sinopharm inactivated COVID-19 vaccine (Cohort 1) or one dose of Comirnaty (Cohort 2).

Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05323461)

**Short title**

A Study to Evaluate the Immunogenicity and Safety of Two Recombinant Protein COVID-19 Vaccines in Population Aged ≥18 Years as Booster Vaccines

Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05323461)

**Official title**

A Randomized, Double-blind, and Positive-controlled Phase III Clinical Trial to Evaluate the Immunogenicity and Safety of SCTV01C (A Bivalent SARS-CoV-2 Trimeric Spike Protein Vaccine) and SCTV01E (A COVID-19 Alpha/Beta/Delta/Omicron Variants S-Trimer Vaccine) in Population Aged ≥18 Years Previously Vaccinated With Either Inactivated or mRNA COVID-19 Vaccine or Previously Diagnosed With COVID-19

Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05323461)

## Status and phase

**Control arm**

Active comparator

Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05323461)

**Registry reports results**

No

Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05323461)

**Listing at source**

Listed

Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05323461)

**Recruitment status**

Unknown

Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05323461)

**Phase**

Phase 3

Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05323461)

**Study type**

Interventional

Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05323461)

## Dates

**Completion date**

2023-05-01

Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05323461)

**First posted**

2022-04-12

Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05323461)

**Registry last updated**

2023-04-10

Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05323461)

**Primary completion date**

2022-10-28

Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05323461)

**Start date**

2022-05-30

Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05323461)

## Size and sites

**Participants**

1,800

Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05323461)

**Participant count basis**

Estimated

Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05323461)

**Planned participants**

1,800

Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05323461)

**Protocol amendments**

1

Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05323461)

**Number of sites**

1

Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05323461)

## Sponsor and oversight

**Registry sponsor category**

Industry

Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05323461)

**Lead sponsor**

Sinocelltech Ltd.

Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05323461)

**Source registry**

ClinicalTrials.gov

Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05323461)

## Identifiers

**Registry ID**

NCT05323461

Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05323461)

**ClinicalTrials.gov ID**

NCT05323461

Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05323461)

**Registry record**

Open registry record

Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05323461)

## Study design

**Allocation**

Randomised

**Model**

Parallel groups

**Purpose**

Prevention

**Masking**

Quadruple masking

**Masked roles**

Participants, Care providers, Investigators, Outcome assessors

Sources for study design

Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05323461)

## Outcomes

### Primary outcomes

1. GMT of nAb against Delta variant on Day 28  
Timeframe: Day 28 after the study vaccination
2. GMT of nAb against Omicron variant on Day 28  
Timeframe: Day 28 after the study vaccination

### Secondary outcomes

1. GMT of nAb against Delta variant on Day 180  
Timeframe: Day 180 after the study vaccination
2. GMT of nAb against Omicron variant on Day 180  
Timeframe: Day 180 after the study vaccination
3. Number of IFN-γ positive (characterizing Th1) and IL-4 positive (characterizing Th2) T cell subsets on Day 28  
Timeframe: Day 28 after the study vaccination
4. Seroresponse rates of nAb to Delta variant on Day 28.  
Timeframe: Day 28 after the study vaccination  
Seroresponse is defined as a change from below the low limit of quantitation \\\[LLOQ\\\] to equal to or above LLOQ, or a ≥4-fold rise if baseline is equal to or above LLOQ in nAb from Day0
5. Seroresponse rates of nAb to Omicron variant on Day 28.  
Timeframe: Day 28 after the study vaccination  
Seroresponse is defined as a change from below the low limit of quantitation \\\[LLOQ\\\] to equal to or above LLOQ, or a ≥4-fold rise if baseline is equal to or above LLOQ in nAb from Day0
6. Incidence and severity of solicited AEs of SCTV01C from Day 0 to Day 7  
Timeframe: Day 0 to Day 7 after the study vaccination
7. Incidence and severity of all unsolicited AEs of SCTV01C from Day 0 to Day 28  
Timeframe: Day 0 to Day 28 after the study vaccination
8. Incidence and severity of SAEs and AESIs of SCTV01C within 180 days  
Timeframe: Day 0 to Day 180 after the study vaccination
9. Incidence and severity of solicited AEs of SCTV01E from Day 0 to Day 7  
Timeframe: Day 0 to Day 7 after the study vaccination
10. Incidence and severity of all unsolicited AEs of SCTV01E from Day 0 to Day 28  
Timeframe: Day 0 to Day 28 after the study vaccination

Sources for outcomes

Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05323461)

## Eligibility

**Sex**

All

**Age groups**

Adults, Older adults

**Minimum age**

18 Years

**Healthy volunteers**

Yes

### Inclusion criteria

1. Male or female aged ≥18 years old when signing ICF;
2. For Subgroup 1 in Cohort 1: Participants who were previously vaccinated with 2 or 3 doses of Sinopharm inactivated COVID-19 vaccine. The interval between the date of last dose and the date of this study vaccination should be 3 to 24 months.  
For Subgroup 2 in Cohort 1: 1) Participants who were previously vaccinated with 2 or 3 doses of Sinopharm inactivated COVID-19 vaccine, with or without COVID-19 history; or 2) Participants who were previously vaccinated with 1 dose of Sinopharm inactivated COVID-19 vaccine and previously diagnosed with COVID-19\. The interval between the date of last dose/COVID-19 diagnosis and the date of this study vaccination should be 3 to 24 months.  
For Cohort 2: 1) Participants who were previously vaccinated with 2 or 3 doses of mRNA COVID-19 vaccine (Comirnaty or mRNA-1273), with or without COVID-19 history; or 2) Participants who were previously vaccinated with 1 doses of mRNA COVID-19 vaccine (Comirnaty or mRNA-1273) and previously diagnosed with COVID-19; or 3) Participants who were previously not vaccinated with any COVID-19 vaccine and previously diagnosed with COVID-19\. The interval between the date of last dose/COVID-19 diagnosis and the date of this study vaccination should be 3 to 24 months.
3. The participant and/or his legally acceptable representative can sign written ICF, and can fully understand the trial procedure, the risk of participating in the trial, and other interventions that can be selected if they do not participate in the trial;
4. The participant and/or his legally acceptable representative have the ability to read, understand, and fill in record cards;
5. Healthy participants or participants with pre-existing medical conditions who are in stable condition. The "pre-existing medical conditions" include but not limited to hypertension, diabetes, chronic cholecystitis and cholelithiasis, chronic gastritis that meet the described criteria. A stable medical condition is defined as disease not requiring significant change in therapy or no need for hospitalization as a consequence of worsening disease state for at least 3 months prior to enrollment;
6. Fertile men and women of childbearing potential voluntarily agree to take effective contraceptive measures from signing ICF to 6 months after the study vaccination; the pregnancy test results of women of childbearing potential are negative on screening.

### Exclusion criteria

1. For Subgroup 1 in Cohort 1 only: Previously diagnosed with COVID-19.
2. Presence of fever within 3 days before the study vaccination;
3. A history of infection or disease related to severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), or other disease corresponding use of immunosuppressants;
4. A history of allergic reactions to any vaccine or drug, such as allergy, urticaria, severe skin eczema, dyspnea, laryngeal edema, and angioneurotic edema;
5. A medical or family history of seizure, epilepsy, encephalopathy and psychosis;
6. Immunocompromised patients suffering from immunodeficiency diseases, important organ diseases, immune diseases (including Guillain-Barre Syndrome \[GBS\], systemic lupus erythematosus, rheumatoid arthritis, asplenia or splenectomy caused by any circumstances, and other immune diseases that may have an impact on immune response in the investigator's opinion), etc.;
7. Long-term use of immunosuppressant therapy or immunomodulatory drugs for ≥14 days within the first six months prior to enrollment. Whereas short-term (≤14 days) use of oral, inhaled and topical steroids are allowed;
8. Patients on antituberculosis therapy;
9. Presence of severe or uncontrollable cardiovascular diseases, or severe or uncontrollable disorders related to endocrine system, blood and lymphatic system, liver and kidney, respiratory system, metabolic and skeletal systems, or malignancies (skin basal cell carcinoma and carcinoma in-situ of cervix are exceptions and will not be excluded), such as severe heart failure, severe pulmonary heart disease, unstable angina, liver failure, or uremia;
10. Contraindications for intramuscular injection or intravenous blood sampling, including thrombocytopenia and other blood coagulation disorders;
11. Participants who received any immunoglobulin or blood products in the previous 3 months before enrollment, or plan to receive similar products during the study;
12. Participants who received other investigational drugs within 1 month before the study vaccination;
13. Participants who is at the acute state of disease, such as acute onset of chronic heart failure, acute sore throat, hypertensive encephalopathy, acute pneumonia, acute renal insufficiency, acute cholecystitis;
14. Participants received other drugs or vaccines used to prevent COVID-19, but participants previously received Sinopharm inactivated COVID-19 vaccine, Comirnaty or mRNA-1273 will not be excluded;
15. Participants vaccinated with influenza vaccine within 14 days or with other vaccines within 28 days before the study vaccination;
16. Those who donated blood or had blood loss (≥450 mL) within 3 months before the vaccination or plan to donate blood during the study period;
17. Those who are pregnant or breast-feeding or plan to be pregnant during the study period;
18. Those who plan to donate ovum or sperms during the study period;
19. Those who cannot follow the trial procedures, or cannot cooperate to complete the study due to planned relocation or long-term outing;
20. Those unsuitable for participating in the clinical trial as determined by the investigator because of other abnormalities that are likely to confuse the study results, or non-conformance with the maximal benefits of the participants;
21. Those who are tested positive for HIV in terms of serology.

Sources for eligibility

Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05323461)

## Sites

- Al Kuwait Hospital (Al Baraha Hospital)Dubai, United Arab Emirates

Sources for sites

Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05323461)

## References

- PubMed 37731938  
Source: [pubmed.ncbi.nlm.nih.gov](https://pubmed.ncbi.nlm.nih.gov/37731938/)
Related publication
- PubMed 36598621  
Source: [pubmed.ncbi.nlm.nih.gov](https://pubmed.ncbi.nlm.nih.gov/36598621/)
Related publication

Sources for references

Source: [clinicaltrials.gov](https://clinicaltrials.gov/study/NCT05323461)

## Related records

### Drugs (1)

- [Tozinameran](https://trialight.com/data/asset/tozinameran-bb0e4f65-bf06-4152-bd75-c7c1f5505a9d.md)

### Lead sponsors (1)

- [Sinocelltech Ltd.](https://trialight.com/data/company/sinocelltech-ltd-26ae8da6-0626-457a-96bd-70bfdcada535.md)

### Conditions (1)

- [COVID-19](https://trialight.com/data/condition/covid-19-13f0ebf3-c291-557d-bdef-93563d077103.md) Primary condition

---

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