A Phase 3 interventional study of S-268019-b and Placebo in SARS-CoV-2, sponsored by Shionogi. Completed at 1 site in Vietnam. Open to participants aged 18 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2025-11-28.
Sponsored by Shionogi · Phase 3, Interventional, and Prevention
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.
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).
Shionogi is the lead sponsor of 104 studies on the registry; 10 are open to participants now.
Of its 39 completed or terminated interventional studies of FDA-regulated products, 21 (54%) have results posted.
Counted across the registry records on this site, refreshed daily.
Exclusion Criteria:
Other inclusion and exclusion criteria may apply.
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.
Drug: S-268019-b · Drug: Placebo
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.
Drug: S-268019-b · Drug: Placebo
Solution for IM injection
Saline solution for IM injection
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.
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
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.
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
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.
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
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.
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
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.
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
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.
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
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.
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
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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: 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.
Time frame: Day 57
| Milestone | S-268019-b Then Placebo | Placebo Then S-268019-b |
|---|---|---|
| Started | 6600 | 3302 |
| Received at least 1 dose of study drug | 6581 | 3285 |
| Modified intent to treat (mitt) | 5596 | 2805 |
| Immunogenicity subset | 64 | 34 |
| Completed | 5315 | 2602 |
| Not completed | 1285 | 700 |
| Withdrew: Withdrawal by subject | 409 | 199 |
| Withdrew: Suspected pregnancy | 1 | 0 |
| Withdrew: Pregnancy | 20 | 14 |
| Withdrew: Physician decision | 686 | 401 |
| Withdrew: Lost to follow-up | 106 | 42 |
| Withdrew: Death | 23 | 18 |
| Withdrew: Coronavirus disease 2019 (covid-19) | 4 | 3 |
| Withdrew: Adverse event | 36 | 23 |
| Milestone | S-268019-b Then Placebo | Placebo Then S-268019-b |
|---|---|---|
| Started | 5315 | 2602 |
| Received at least 1 dose of study drug | 5150 | 2502 |
| Safety analysis set (sas) | 6581 | 3285 |
| Completed | 5123 | 2503 |
| Not completed | 192 | 99 |
| Withdrew: Withdrawal by subject | 95 | 57 |
| Withdrew: Pregnancy | 6 | 1 |
| Withdrew: Physician decision | 49 | 24 |
| Withdrew: Lost to follow-up | 23 | 8 |
| Withdrew: Death | 10 | 5 |
| Withdrew: Adverse event | 9 | 4 |
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.
| Participants | S-268019-b | Placebo |
|---|---|---|
| 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 | 323 | 239 |
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.
| Participants | S-268019-b | Placebo |
|---|---|---|
| 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 | 0 | 1 |
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.
| Participants | S-268019-b | Placebo |
|---|---|---|
| Number of Participants With First Occurrence of SARS-CoV-2 RT-PCR-Positive Symptomatic COVID-19 in the Initial Vaccination Period | 457 | 313 |
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.
| Participants | S-268019-b | Placebo |
|---|---|---|
| Number of Participants With First Occurrence of SARS-CoV-2 RT-PCR-Positive Severe COVID-19 in the Initial Vaccination Period | 0 | 1 |
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.
| Participants | S-268019-b | Placebo |
|---|---|---|
| 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 | 331 | 242 |
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.
| Participants | S-268019-b | Placebo |
|---|---|---|
| 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 | 0 | 1 |
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.
| Participants | S-268019-b | Placebo |
|---|---|---|
| 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 | 479 | 324 |
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.
| Participants | S-268019-b | Placebo |
|---|---|---|
| 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 | 0 | 1 |
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.
| Participants | S-268019-b | Placebo |
|---|---|---|
| Number of Participants With First Occurrence of Asymptomatic SARS-CoV-2 Infection in the Initial Vaccination Period | 2543 | 1345 |
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.
| Percentage of Participants | S-268019-b | Placebo |
|---|---|---|
| Percentage of Participants Experiencing Solicited Systemic Adverse Events | 32.7 (31.5 to 33.8) | 23.4 (22.0 to 24.9) |
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.
| Percentage of Participants | S-268019-b | Placebo |
|---|---|---|
| Percentage of Participants Experiencing Solicited Local Adverse Events | 37.7 (36.5 to 38.9) | 14.6 (13.4 to 15.8) |
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.
| Titer | S-268019-b | Placebo |
|---|---|---|
| Geometric Mean Titer (GMT) of SARS-CoV-2 Neutralizing Antibody | 34.66 (27.04 to 44.41) | 2.69 (2.31 to 3.14) |
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.
| Fold Rise | S-268019-b | Placebo |
|---|---|---|
| Geometric Mean Fold Rise (GMFR) of SARS-CoV-2 Neutralizing Antibody | 13.86 (10.82 to 17.76) | 1.08 (0.92 to 1.25) |
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.
| Percentage of Participants | S-268019-b | Placebo |
|---|---|---|
| Seroconversion Rate of SARS-CoV-2 Neutralizing Antibody | 93.1 (83.3 to 98.1) | 3.6 (0.1 to 18.3) |
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.
| Titer | S-268019-b | Placebo |
|---|---|---|
| GMT of Anti-SARS-CoV-2 S-protein Immunoglobulin G (IgG) Antibody | 25209.25 (17163.57 to 37026.44) | 6.39 (3.10 to 13.19) |
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.
| Fold Rise | S-268019-b | Placebo |
|---|---|---|
| GMFR of Anti-SARS-CoV-2 S-protein IgG Antibody | 6710.95 (4556.29 to 9884.54) | 1.46 (0.75 to 2.85) |
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.
| Percentage of Participants | S-268019-b | Placebo |
|---|---|---|
| Seroconversion Rate of Anti-SARS-CoV-2 S-protein IgG Antibody | 98.2 (90.6 to 100.0) | 7.1 (0.9 to 23.5) |
Collected over Day 1 (Baseline) through Day 435. Non-serious events are listed at a 5% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| S-268019-b | 29/9,083 (0.3%) | 154/9,083 (1.7%) | 3,647/9,083 (40.2%) |
| Placebo | 29/8,435 (0.3%) | 136/8,435 (1.6%) | 1,548/8,435 (18.4%) |
| Event | S-268019-b | Placebo |
|---|---|---|
| PneumoniaInfections and infestations | 8/9083 | 9/8435 |
| DeathGeneral disorders | 9/9083 | 3/8435 |
| COVID-19Infections and infestations | 8/9083 | 7/8435 |
| Abortion spontaneousPregnancy, puerperium and perinatal conditions | 2/2978 | 2/2781 |
| BronchitisInfections and infestations | 5/9083 | 4/8435 |
| Vestibular disorderEar and labyrinth disorders | 2/9083 | 4/8435 |
| GastritisGastrointestinal disorders | 3/9083 | 4/8435 |
| Multiple injuriesInjury, poisoning and procedural complications | 4/9083 | 4/8435 |
| AppendicitisInfections and infestations | 4/9083 | 2/8435 |
| Angina pectorisCardiac disorders | 4/9083 | 0/8435 |
| Event | S-268019-b | Placebo |
|---|---|---|
| PainGeneral disorders | 1689/9083 | 290/8435 |
| FatigueGeneral disorders | 1405/9083 | 468/8435 |
| HeadacheNervous system disorders | 1235/9083 | 446/8435 |
| MyalgiaMusculoskeletal and connective tissue disorders | 1029/9083 | 255/8435 |
| Injection site painGeneral disorders | 923/9083 | 219/8435 |
| PyrexiaGeneral disorders | 676/9083 | 185/8435 |
Full Analysis Set (FAS): all randomized participants who received at least 1 dose of the study intervention during the Initial Vaccination Period.
| Age, Customized(Participants) | S-268019-b Then Placebo | Placebo Then S-268019-b | Total |
|---|---|---|---|
| <30 years old | 1863 | 954 | 2817 |
| ≥30 to <40 years old | 1559 | 717 | 2276 |
| ≥40 to <50 years old | 1194 | 616 | 1810 |
| ≥50 to <60 years old | 1017 | 521 | 1538 |
| ≥60 to <65 years old | 418 | 215 | 633 |
| ≥65 years old | 530 | 262 | 792 |
| Sex: Female, Male(Participants) | S-268019-b Then Placebo | Placebo Then S-268019-b | Total |
|---|---|---|---|
| Female | 2151 | 1131 | 3282 |
| Male | 4430 | 2154 | 6584 |
| Ethnicity (NIH/OMB)(Participants) | S-268019-b Then Placebo | Placebo Then S-268019-b | Total |
|---|---|---|---|
| Hispanic or Latino | 18 | 5 | 23 |
| Not Hispanic or Latino | 6552 | 3269 | 9821 |
| Unknown or Not Reported | 11 | 11 | 22 |
| Race (NIH/OMB)(Participants) | S-268019-b Then Placebo | Placebo Then S-268019-b | Total |
|---|---|---|---|
| American Indian or Alaska Native | 2 | 0 | 2 |
| Asian | 6569 | 3275 | 9844 |
| Native Hawaiian or Other Pacific Islander | 0 | 0 | 0 |
| Black or African American | 0 | 1 | 1 |
| White | 0 | 0 | 0 |
| More than one race | 0 | 0 | 0 |
| Unknown or Not Reported | 10 | 9 | 19 |
| anti-Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) N-protein Antibody Test(Participants) | S-268019-b Then Placebo | Placebo Then S-268019-b | Total |
|---|---|---|---|
| Positive | 816 | 409 | 1225 |
| Negative | 5719 | 2860 | 8579 |
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