SARS-CoV-2Phase 3NCT05212948
A Study of S-268019 for the Prevention of COVID-19
A Phase 3 study testing S-268019-b in people with SARS-CoV-2, run by Shionogi at 1 site in Vietnam.
Trial summary
The main purpose of this study is to assess the efficacy of S-268019-b for the prevention of COVID-19 in the initial vaccination period prior to crossover in participants without evidence of infection before vaccination as compared to placebo. Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- SARS-CoV-2
- What is being tested?
- S-268019-b
- Type of treatment
- Vaccines, Injection or infusion
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 9,902 participants
- Where
- 1 siteVietnam
- Study dates
- 25 Dec 2021to 19 Jul 2023
- 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 18 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Agree not to participate in any other SARS-CoV-2 prevention trial during the study follow-up.
- Capable of using Diary without difficulties (if applicable, with assistance by caregiver).
Who cannot join
- Current or history of a laboratory-confirmed diagnosis of SARS-CoV-2 infection or COVID-19.
- Unstable current cardiovascular, respiratory, hepatic, renal, gastrointestinal, endocrine, hematological, or neurological disease that, in the opinion of the investigator or subinvestigator, would constitute a safety concern or confound data interpretation.
- Immunosuppression (immunodeficiency, acquired immunodeficiency syndrome [AIDS], use of systemic steroids, use of immunosuppressants within the past 6 months prior to the first dose of study intervention, treatment for malignant tumors, other immunosuppressive therapy).
- Previous vaccination against SARS-CoV-2.
- Any inactivated vaccine received within 14 days prior to the first dose of study intervention.
- Any live vaccine received within 28 days prior to the first dose of study intervention.
- Immunoglobulin preparations, blood products, or a blood transfusion within 3 months prior to the first dose of study intervention.
- Other inclusion and exclusion criteria may apply.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: A Phase 3, Randomized, Observer-Blind, Placebo- Controlled Cross-over Study to Evaluate the Efficacy, Safety, and Immunogenicity of S-268019 for the Prevention of COVID-19
The main purpose of this study is to assess the efficacy of S-268019-b for the prevention of COVID-19 in the initial vaccination period prior to crossover in participants without evidence of infection before vaccination as compared to placebo.
Read the detailed description
Eligible participants will be randomized to receive either S-268019-b or placebo first and then will be crossed over to receive the opposite intervention. The study will consist of two treatment periods, an initial vaccination period (Day 1 to Day 224), and a crossover vaccination period (Day 225 to Day 435).
- Conditions
- SARS-CoV-2
- Being tested
- S-268019-b, Placebo
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
S-268019-bDrug
Solution for IM injection
PlaceboDrug
Saline solution for IM injection
| Study group | Role | What they receive |
|---|---|---|
| S-268019-b, Then Placebo | Experimental | Participants will first receive a dose of S-268019-b via intramuscular (IM) injection on Day 1 and Day 29 during the initial vaccination period. After the initial vaccination period, participants will then receive a placebo IM injection (matching S-268019-b) on Day 225 and Day 253. Receives: Drug: S-268019-b; Drug: Placebo |
| Placebo, Then S-268019-b | Experimental | Participants will first receive a dose of placebo IM injection (matching S-268019-b) on Day 1 and Day 29 during the initial vaccination period. After the initial vaccination period, participants will then receive S-268019-b IM injection on Day 225 and Day 253. Receives: Drug: S-268019-b; Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Number of Participants With First Occurrence of SARS-CoV-2 Reverse Transcription Polymerase Chain Reaction (RT-PCR)-Positive Symptomatic COVID-19 With Onset at Least 14 Days Following Second Vaccination During the Initial Vaccination Period
Participants without evidence of infection before vaccination (that is, seronegative and PCR-negative at baseline) were determined to have symptomatic COVID-19 when at least 1 protocol-specified COVID-19-related symptom and a positive RT-PCR test result were confirmed by the medical monitor within at least 14 days following the second vaccination. RT-PCR testing was based upon nasopharyngeal swab sampling at protocol-specified timepoints.
Measured: From Day 43 (14 days after the second dose administration) to Day 224
Secondary outcomes (16)
Number of Participants With First Occurrence of SARS-CoV-2 RT-PCR-Positive Severe COVID-19 in the Initial Vaccination Period With Onset at Least 14 Days Following Second Vaccination
For participants without evidence of infection before vaccination (that is, seronegative and PCR-negative at baseline) who were confirmed to have symptomatic COVID-19 within at least 14 days following the second vaccination, the investigator evaluated if the maximum intensity during the course of the disease met protocol-specified criteria for severe COVID-19.
Measured: From Day 43 (14 days after the second dose administration) to Day 224
Number of Participants With First Occurrence of SARS-CoV-2 RT-PCR-Positive Symptomatic COVID-19 in the Initial Vaccination Period
Participants without evidence of infection before vaccination (that is, seronegative and PCR-negative at baseline) were determined to have symptomatic COVID-19 when at least 1 protocol-specified COVID-19-related symptom and a positive RT-PCR test result were confirmed by the medical monitor. RT-PCR testing was based upon nasopharyngeal swab sampling at protocol-specified timepoints.
Measured: Up to Day 224
Number of Participants With First Occurrence of SARS-CoV-2 RT-PCR-Positive Severe COVID-19 in the Initial Vaccination Period
For participants without evidence of infection before vaccination (that is, seronegative and PCR-negative at baseline) who were confirmed to have symptomatic COVID-19, the investigator evaluated if the maximum intensity during the course of the disease met the protocol-specified criteria for severe COVID-19.
Measured: Up to Day 224
Number of Participants With First Occurrence of SARS-CoV-2 RT-PCR-Positive Symptomatic COVID-19 in the Initial Vaccination Period Regardless of Serostatus or PCR Status at Baseline With Onset at Least 14 Days Following Second Vaccination
A participant was determined to have symptomatic COVID-19 when at least 1 protocol-specified COVID-19-related symptom and a positive RT-PCR test result were confirmed by the medical monitor within at least 14 days following the second vaccination. RT-PCR testing was based upon nasopharyngeal swab sampling at protocol-specified timepoints.
Measured: From Day 43 (14 days after the second dose administration) to Day 224
Number of Participants With First Occurrence of SARS-CoV-2 RT-PCR-Positive Severe COVID-19 in the Initial Vaccination Period With Onset at Least 14 Days Following Second Vaccination Regardless of Serostatus or PCR Status at Baseline
For participants confirmed to have symptomatic COVID-19 within at least 14 days following the second vaccination, the investigator evaluated if the maximum intensity during the course of the disease met the protocol-specified criteria for severe COVID-19.
Measured: From Day 43 (14 days after the second dose administration) to Day 224
Number of Participants With First Occurrence of SARS-CoV-2 RT-PCR-Positive Symptomatic COVID-19 in the Initial Vaccination Period Regardless of Serostatus or PCR Status at Baseline
A participant was determined to have symptomatic COVID-19 when the participant had at least 1 protocol-specified COVID-19-related symptom and a positive RT-PCR test result confirmed by the medical monitor. RT-PCR testing was based upon nasopharyngeal swab sampling at protocol-specified timepoints.
Measured: Up to Day 224
Number of Participants With First Occurrence of SARS-CoV-2 RT-PCR-Positive Severe COVID-19 in the Initial Vaccination Period Regardless of Serostatus or PCR Status at Baseline
For participants confirmed to have symptomatic COVID-19, the investigator evaluated if the maximum intensity during the course of the disease met the protocol-specified criteria for severe COVID-19.
Measured: Up to Day 224
Number of Participants With First Occurrence of Asymptomatic SARS-CoV-2 Infection in the Initial Vaccination Period
For participants without evidence of infection before vaccination (that is, seronegative and PCR-negative at baseline), asymptomatic SARS-CoV-2 infection was defined as having a positive result of anti-SARS-CoV-2 N-protein antibody test beginning 14 days following the second vaccination and not meeting the protocol-specified criteria of symptomatic COVID-19. Antibodies to SARS-CoV-2 N-protein were used to determine both natural infection and the incidence of asymptomatic infection acquired during the initial vaccination period of the study.
Measured: From Day 43 (14 days after the second dose administration) to Day 224
Percentage of Participants Experiencing Solicited Systemic Adverse Events
An adverse event (AE) was defined as any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. Solicited systemic AEs were defined as the AEs that occurred within the first 7 days after each vaccination and were classified as one of the following: fever, nausea/vomiting, diarrhea, headache, fatigue, and myalgia. A summary of all Serious Adverse Events and Other Adverse Events (nonserious) regardless of causality is located in the 'Reported Adverse Events' Section.
Measured: Up to Day 224
Percentage of Participants Experiencing Solicited Local Adverse Events
An AE was defined as any untoward medical occurrence in a clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. Solicited local AEs were defined as the AEs that occurred within the first 7 days after each vaccination and were classified as one of the following: pain, erythema/redness, induration, and swelling. A summary of all Serious Adverse Events and Other Adverse Events (nonserious) regardless of causality is located in the 'Reported Adverse Events' Section.
Measured: Up to Day 224
Geometric Mean Titer (GMT) of SARS-CoV-2 Neutralizing Antibody
Blood samples for immunogenicity assessments were collected during protocol-specified study visits. The serum neutralizing antibody level against SARS-CoV-2 was measured by a live virus neutralization assay. The GMT was calculated by taking the back transformation of the arithmetic mean of log-transformed titers. The 95% confidence interval was calculated based on the Student's t distribution of the log-transformed values, then back transformed to the original scale.
Measured: Day 57
Geometric Mean Fold Rise (GMFR) of SARS-CoV-2 Neutralizing Antibody
Blood samples for immunogenicity assessments were collected during protocol-specified study visits. The serum neutralizing antibody level against SARS-CoV-2 was measured by a live virus neutralization assay. The GMFR was calculated by taking the back transformation of the arithmetic mean of the change from baseline in log-transformed titers. The 95% confidence interval was calculated based on the Student's t distribution of the change from baseline in the log-transformed values, then back transformed to the original scale.
Measured: Day 57
Seroconversion Rate of SARS-CoV-2 Neutralizing Antibody
Blood samples for immunogenicity assessments were collected during protocol-specified study visits. The serum neutralizing antibody level against SARS-CoV-2 was measured by a live virus neutralization assay. Seroconversion was defined as a 4-times or higher from baseline in SARS-CoV-2 neutralizing antibody titer, where titer values reported as below the lower limit of quantification (LLOQ) were replaced by 0.5*LLOQ. Seroconversion rate was defined as the percentage of participants that underwent seroconversion. The 95% confidence interval was calculated using the Clopper-Pearson method.
Measured: Day 57
GMT of Anti-SARS-CoV-2 S-protein Immunoglobulin G (IgG) Antibody
Blood samples for immunogenicity assessments were collected during protocol-specified study visits. The serum neutralizing antibody level against SARS-CoV-2 (anti-spike protein IgG antibody) was measured by a chemiluminescence immunoassay. The GMT was calculated by taking the back transformation of the arithmetic mean of log- transformed titers. The 95% confidence interval was calculated based on the Student's t distribution of the log-transformed values, then back transformed to the original scale.
Measured: Day 57
GMFR of Anti-SARS-CoV-2 S-protein IgG Antibody
Blood samples for immunogenicity assessments were collected during protocol-specified study visits. The anti-spike protein IgG antibody was measured by a chemiluminescence immunoassay. The GMFR was calculated by taking the back transformation of the arithmetic mean of the change from baseline in log-transformed titers. The 95% confidence interval was calculated based on the Student's t distribution of the change from baseline in the log-transformed values, then back transformed to the original scale.
Measured: Day 57
Seroconversion Rate of Anti-SARS-CoV-2 S-protein IgG Antibody
Blood samples for immunogenicity assessments were collected during protocol-specified study visits. The anti-spike protein IgG antibody was measured by a chemiluminescence immunoassay. Seroconversion was defined as a 4-times or higher from baseline in anti-spike protein IgG antibody titer, where titer values reported as below the LLOQ are replaced by 0.5*LLOQ and titer values reported as above the upper limit of quantification (ULOQ) are imputed at the ULOQ value. Seroconversion rate was defined as the percentage of participants that underwent seroconversion. The 95% confidence interval was calculated using the Clopper-Pearson method.
Measured: Day 57
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted28 Jan 2022
- Study start25 Dec 2021
- Primary completion19 Dec 2022
- Study completion19 Jul 2023
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 SARS-CoV-2Studies of the same condition, open and under way.
- More trials run by ShionogiThe sponsor's other registered studies.
- 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
- Crossover
- Masking
- Triple blind
- Who is masked
- Participant, Care provider, Investigator
- Enrolment
- 9,902 participants (actual)
Sponsor and investigators
- Lead sponsor
- Shionogi
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05212948
- Sponsor's protocol ID
- 2126U0232
- Status last verified
- Nov 2025
- First submitted
- 24 Jan 2022
- Last updated
- 28 Nov 2025
- Results posted
- Yes, on ClinicalTrials.gov
- FDA-regulated drug
- No
- FDA-regulated device
- No
Publications
Dinh Thiem V, Van Anh PT, Van Men C, Hung DT, Pollard AJ, Kamitani A, Tada Y, Fukuyama H, Iwasaki Y, Ariyasu M, Sonoyama T. A SARS-CoV-2 recombinant spike protein vaccine (S-268019-b) for COVID-19 prevention during the Omicron-dominant period: A phase 3, randomised, placebo-controlled clinical trial. Vaccine. 2024 Jun 20;42(17):3699-3709. doi: 10.1016/j.vaccine.2024.04.084. Epub 2024 May 10.
PubMed 38734495
Study at a glance
From the registry record, last updated by the sponsor on 28 Nov 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Phase 3, Randomized, Observer-Blind, Placebo- Controlled Cross-over Study to Evaluate the Efficacy, Safety, and Immunogenicity of S-268019 for the Prevention of COVID-19
- ClinicalTrials.gov ID
- NCT05212948
- Acronym / sponsor ID
- 2126U0232
- Conditions
- SARS-CoV-2
- Phase
- Phase 3
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 9,902 participants (actual)
- Lead sponsor
- ShionogiIndustry (pharma, biotech, devices)
- Study start
- 25 Dec 2021 (actual)
- Primary completion
- 19 Dec 2022 (actual)
- Study completion
- 19 Jul 2023 (actual)
- First posted
- 28 Jan 2022 (actual)
- Results
- Posted 28 Nov 2025
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The main purpose of this study is to assess the efficacy of S-268019-b for the prevention of COVID-19 in the initial vaccination period prior to crossover in participants without evidence of infection before vaccination as compared to placebo.
Detailed description
Eligible participants will be randomized to receive either S-268019-b or placebo first and then will be crossed over to receive the opposite intervention. The study will consist of two treatment periods, an initial vaccination period (Day 1 to Day 224), and a crossover vaccination period (Day 225 to Day 435).
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Triple blind (participant, care provider, investigator)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| S-268019-b, Then Placebo | Experimental | Drug: S-268019-b, Drug: PlaceboParticipants will first receive a dose of S-268019-b via intramuscular (IM) injection on Day 1 and Day 29 during the initial vaccination period. After the initial vaccination period, participants will then receive a placebo IM injection (matching S-268019-b) on Day 225 and Day 253. |
| Placebo, Then S-268019-b | Experimental | Drug: S-268019-b, Drug: PlaceboParticipants will first receive a dose of placebo IM injection (matching S-268019-b) on Day 1 and Day 29 during the initial vaccination period. After the initial vaccination period, participants will then receive S-268019-b IM injection on Day 225 and Day 253. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (2 listed)
- Agree not to participate in any other SARS-CoV-2 prevention trial during the study follow-up.
- Capable of using Diary without difficulties (if applicable, with assistance by caregiver).
Key exclusion criteria (8 listed)
- Current or history of a laboratory-confirmed diagnosis of SARS-CoV-2 infection or COVID-19.
- Unstable current cardiovascular, respiratory, hepatic, renal, gastrointestinal, endocrine, hematological, or neurological disease that, in the opinion of the investigator or subinvestigator, would constitute a safety concern or confound data interpretation.
- Immunosuppression (immunodeficiency, acquired immunodeficiency syndrome [AIDS], use of systemic steroids, use of immunosuppressants within the past 6 months prior to the first dose of study intervention, treatment for malignant tumors, other immunosuppressive therapy).
- Previous vaccination against SARS-CoV-2.
- Any inactivated vaccine received within 14 days prior to the first dose of study intervention.
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 |
|---|---|---|
| S-268019-bSolution for IM injection | Drug | Placebo, Then S-268019-b, S-268019-b, Then Placebo |
| PlaceboSaline solution for IM injection | Drug | Placebo, Then S-268019-b, S-268019-b, Then Placebo |
Primary outcome
Number of Participants With First Occurrence of SARS-CoV-2 Reverse Transcription Polymerase Chain Reaction (RT-PCR)-Positive Symptomatic COVID-19 With Onset at Least 14 Days Following Second Vaccination During the Initial Vaccination Period
Time frame: From Day 43 (14 days after the second dose administration) to Day 224
Participants without evidence of infection before vaccination (that is, seronegative and PCR-negative at baseline) were determined to have symptomatic COVID-19 when at least 1 protocol-specified COVID-19-related symptom and a positive RT-PCR test result were confirmed by the medical monitor within at least 14 days following the second vaccination. RT-PCR testing was based upon nasopharyngeal swab sampling at protocol-specified timepoints.
16 secondary outcomes
Number of Participants With First Occurrence of SARS-CoV-2 RT-PCR-Positive Severe COVID-19 in the Initial Vaccination Period With Onset at Least 14 Days Following Second Vaccination
Time frame: From Day 43 (14 days after the second dose administration) to Day 224
Number of Participants With First Occurrence of SARS-CoV-2 RT-PCR-Positive Symptomatic COVID-19 in the Initial Vaccination Period
Time frame: Up to Day 224
Number of Participants With First Occurrence of SARS-CoV-2 RT-PCR-Positive Severe COVID-19 in the Initial Vaccination Period
Time frame: Up to Day 224
Number of Participants With First Occurrence of SARS-CoV-2 RT-PCR-Positive Symptomatic COVID-19 in the Initial Vaccination Period Regardless of Serostatus or PCR Status at Baseline With Onset at Least 14 Days Following Second Vaccination
Time frame: From Day 43 (14 days after the second dose administration) to Day 224
Number of Participants With First Occurrence of SARS-CoV-2 RT-PCR-Positive Severe COVID-19 in the Initial Vaccination Period With Onset at Least 14 Days Following Second Vaccination Regardless of Serostatus or PCR Status at Baseline
Time frame: From Day 43 (14 days after the second dose administration) to Day 224
Number of Participants With First Occurrence of SARS-CoV-2 RT-PCR-Positive Symptomatic COVID-19 in the Initial Vaccination Period Regardless of Serostatus or PCR Status at Baseline
Time frame: Up to Day 224
Number of Participants With First Occurrence of SARS-CoV-2 RT-PCR-Positive Severe COVID-19 in the Initial Vaccination Period Regardless of Serostatus or PCR Status at Baseline
Time frame: Up to Day 224
Number of Participants With First Occurrence of Asymptomatic SARS-CoV-2 Infection in the Initial Vaccination Period
Time frame: From Day 43 (14 days after the second dose administration) to Day 224
Percentage of Participants Experiencing Solicited Systemic Adverse Events
Time frame: Up to Day 224
Percentage of Participants Experiencing Solicited Local Adverse Events
Time frame: Up to Day 224
Geometric Mean Titer (GMT) of SARS-CoV-2 Neutralizing Antibody
Time frame: Day 57
Geometric Mean Fold Rise (GMFR) of SARS-CoV-2 Neutralizing Antibody
Time frame: Day 57
Seroconversion Rate of SARS-CoV-2 Neutralizing Antibody
Time frame: Day 57
GMT of Anti-SARS-CoV-2 S-protein Immunoglobulin G (IgG) Antibody
Time frame: Day 57
GMFR of Anti-SARS-CoV-2 S-protein IgG Antibody
Time frame: Day 57
Seroconversion Rate of Anti-SARS-CoV-2 S-protein IgG Antibody
Time frame: Day 57
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 28 Nov 2025.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
- Results publication: PubMed 38734495Dinh Thiem V, Van Anh PT, Van Men C, Hung DT, Pollard AJ, Kamitani A, Tada Y, Fukuyama H, Iwasaki Y, Ariyasu M, Sonoyama T. A SARS-CoV-2 recombinant spike protein vaccine (S-268019-b) for COVID-19 prevention during the Omicron-dominant period: A phase 3, randomised, placebo-controlled clinical trial. Vaccine. 2024 Jun 20;42(17):3699-3709. doi: 10.1016/j.vaccine.2024.04.084. Epub 2024 May 10.
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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.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 3 study testing S-268019-b in people with SARS-CoV-2, run by Shionogi at 1 site in Vietnam.
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 2 inclusion and 8 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 28 Nov 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Vietnam. 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 28 Nov 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?
Number of Participants With First Occurrence of SARS-CoV-2 Reverse Transcription Polymerase Chain Reaction (RT-PCR)-Positive Symptomatic COVID-19 With Onset at Least 14 Days Following Second Vaccination During the Initial Vaccination Period (time frame: From Day 43 (14 days after the second dose administration) to Day 224). 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 NCT05212948, 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 28 Nov 2025.