A Phase 3 interventional study of Tozinameran - Standard Dose and Tozinameran - Fractional Dose in COVID-19, sponsored by Murdoch Childrens Research Institute. Completed at 1 site in Mongolia. Open to participants aged 18 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-03-24.
Sponsored by Murdoch Childrens Research Institute · Phase 3, Interventional, and Prevention
This clinical trial is a single-blind, randomised study to determine the reactogenicity and immunogenicity of severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) vaccine (Pfizer-BioNTech) as booster dose in adults, who have previously received either Sinopharm (BBIBP-CorV®), AstraZeneca (ChAdOx1-S, or Vaxzevria®) or Sputnik V (Gam-COVID-Vac®) as their primary doses 6 to 9 months earlier. Both standard and fractional doses will be tested.
Participants are healthy adults aged 18 years or older, with no upper age limit. Procedures will be implemented to ensure participants of all ages (aged 18 and above) are included and that there is an even age distribution (\<50 and ≥50 years) in each group. There will be a total of 6 groups (Sinopharm-standard dose Pfizer, Sinopharm-fractional dose Pfizer, AstraZeneca-standard dose Pfizer, AstraZeneca-fractional dose Pfizer, Sputnik - standard dose Pfizer, Sputnik - fractional dose Pfizer), with 200 participants per group for Sinopharm and 100 for AstraZeneca and Sputnik.
As per brief summary
7,990 studies on the registry are indexed under COVID-19; 466 are open to participants now.
This study's enrollment of 601 is above the median of 102 across 4,364 interventional studies indexed under COVID-19.
Browse COVID-19 studies →Murdoch Childrens Research Institute is the lead sponsor of 99 studies on the registry; 34 are open to participants now.
Of its 5 completed or terminated interventional studies of FDA-regulated products, 3 (60%) have results posted.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Immunosuppression
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Biological/Vaccine: Tozinameran - Standard Dose Other Names: BNT162b2 Comirnaty Pfizer Covid-19 vaccine Tozinameran is a single-stranded, 5'-capped messenger RNA (mRNA) produced using a cellfree in vitro transcription from the corresponding DNA templates, encoding the viral spike (S) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Dose - 30 µg in 0.3 ml. Liquid for injection. Single dose.
Biological: Tozinameran - Standard Dose
Biological/Vaccine: Tozinameran - Standard Dose Other Names: BNT162b2 Comirnaty Pfizer Covid-19 vaccine Tozinameran is a single-stranded, 5'-capped messenger RNA (mRNA) produced using a cellfree in vitro transcription from the corresponding DNA templates, encoding the viral spike (S) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Dose - 15 µg in 0.3 ml. Liquid for injection. Single dose.
Biological: Tozinameran - Fractional Dose
Tozinameran is a single-stranded, 5'-capped messenger RNA (mRNA) produced using a cellfree in vitro transcription from the corresponding DNA templates, encoding the viral spike (S) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Dose - 30 µg in 0.3 ml. Liquid for injection. Single dose.
Also known as: BNT162b2, Comirnaty, Pfizer Covid-19 vaccine
Tozinameran is a single-stranded, 5'-capped messenger RNA (mRNA) produced using a cellfree in vitro transcription from the corresponding DNA templates, encoding the viral spike (S) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Dose - 15 µg in 0.15 ml. Liquid for injection. Single dose.
Also known as: BNT162b2, Comirnaty, Pfizer Covid-19 vaccine
Seroresponse
Serum samples collected at 28-days post booster vaccination from all groups will be evaluated for SARS-CoV-2 specific IgG antibodies using IgG ELISA. The primary endpoint is the seroresponse rate at the Day-28 visit. The seroresponse rate at the individual level is defined as either a ≥4-fold rise in binding antibodies at the Day-28 visit compared to baseline (pre-vaccination) with a titre of \<200 BAU/ml, a ≥2-fold rise among participants with a baseline (pre-vaccination) titre of \>200 BAU/ml, or a ≥4-times the lower limit of detection if baseline levels are lower than the limit of detection.
Time frame: 28-days post booster vaccination
Solicited Grade 3 or 4 Local or Systemic Reaction
Questionnaire to document solicited reactions is developed specifically for this study. Data will be reported as the proportion of participants who report grade 3 or 4 reactions by each intervention arm. Solicited reactions such as pain, tenderness, erythema/redness, induration, swelling, fever, nausea, vomiting, headache, fatigue/malaise, myalgia, arthralgia, diarrhea, enlarged lymph nodes will be collected from the participants 7 days post-vaccination.
Time frame: 7 days post booster vaccination
Seroresponse by Priming Vaccine Strata
Serum samples collected at 28-days post booster vaccination from all groups will be evaluated for SARS-CoV-2 specific IgG antibodies using IgG ELISA. The primary endpoint is the seroresponse rate at the Day-28 visit. The seroresponse rate at the individual level is defined as either a ≥4-fold rise in binding antibodies at the Day-28 visit compared to baseline (pre-vaccination) with a titre of \<200 BAU/ml, a ≥2-fold rise among participants with a baseline (pre-vaccination) titre of \>200 BAU/ml, or a ≥4-times the lower limit of detection if baseline levels are lower than the limit of detection. Priming strata (previously COVID vaccination): AstraZeneca (ChAdOx1-S, or Vaxzevria®); Sinopharm (BBIBP-CorV®); Sputnik V (Gam-COVID-Vac®)
Time frame: 28-days post booster vaccination
SARS-CoV-2 Specific IgG Antibodies at Day-28
Serum samples collected at 28-days post booster vaccination from all groups will be evaluated for SARS-CoV-2 specific IgG antibodies using IgG ELISA.
Time frame: 28-days post booster vaccination
SARS-CoV-2 Specific IgG Antibodies at Day-28 by Priming Vaccine Strata
Serum samples collected at 28-days post booster vaccination from all groups will be evaluated for SARS-CoV-2 specific IgG antibodies using IgG ELISA. Priming strata (previously COVID vaccination): AstraZeneca (ChAdOx1-S, or Vaxzevria®); Sinopharm (BBIBP-CorV®); Sputnik V (Gam-COVID-Vac®)
Time frame: 28-days post booster vaccination
SARS-CoV-2 Specific IgG Antibodies at Baseline (Pre-booster), 28 Days, 6 Months, 12 Months, 18 Months, and 24 Months Post-booster Vaccination.
Serum samples collected at baseline (pre booster), 28 days, 6 months, 12 months, 18 months, and 24 months post booster vaccination from the study arms will be evaluated for SARS-CoV-2 specific IgG antibodies using the commercial Euroimmun S1 IgG ELISA. Data will be reported as binding antibody units (BAU)/mL and presented as geometric mean concentration (GMC) and 95% confidence intervals (CI).
Time frame: Baseline (pre booster), 28 days, 6 months, 12 months, 18 months, and 24 months post-booster vaccination.
SARS-CoV-2 Specific Neutralising Antibodies at Baseline (Pre-booster), 28 Days, 6 Months, 12 Months, 18 Months, and 24 Months Post-booster Vaccination Measured by Surrogate Virus Neutralisation Test (sVNT).
Serum samples collected at baseline (pre booster), 28 days-, 6- and 12-months post booster vaccination from all groups will be evaluated for SARS-CoV-2 specific neutralising antibodies using the GenScript® cPass surrogate virus neutralization test (sVNT) for both wild-type and Omicron variant. Neutralising antibody response will be reported as percentage (%) inhibition of receptor binding domain-angiotensin-converting enzyme 2 (RBD-ACE2) binding relative to a positive control.
Time frame: Baseline (pre-booster), 28 days, 6 months, 12 months, 18 months, and 24 months post-booster vaccination.
SARS-CoV-2 Specific Neutralising Antibodies at Baseline (Pre Booster), 28 Days-, 6- and 12-months Post Booster Vaccination Measured by SARS-CoV-2 Microneutralisation Assay
A subset of samples (20%) from all four timepoints will be assessed using a SARS-CoV-2 microneutralisation assay to both the wild type (vaccine) strain and for two SARS-CoV-2 Variants of concern. Neutralizing antibody will be reported as endpoint titre.
Time frame: Baseline (pre booster), 28 days-, 6- and 12-months post booster vaccination
Interferon Gamma (IFNγ) Concentrations in International Units (IU)/mL
IFN-γ concentrations (IU/mL) as a measure of cellular immunity will be assessed in a subset of participants. IFN-γ production will be stimulated using QuantiFERON Human IFN-γ SARS-CoV-2 (Qiagen) and quantified by ELISA. Results are summarised as geometric mean concentrations (GMCs) with 95% confidence intervals.
Time frame: Baseline (pre booster), 28 days, 6-, 12 -, 18-, and 24-months post booster vaccination
Number of IFNγ Producing Cells/Million PBMCs
Applicable to the subset participants with additional blood collection. IFNγ producing cells as a measurement of cellular immunity will be assessed on a subset of the participants (40%) from each group. IFN-γ Enzyme-Linked ImmunoSpot (Elispot) assay will be performed on isolated peripheral blood mononuclear cells (PBMCs). Data will be reported as number of IFNγ producing cells/million and presented using means and 95% CI.
Time frame: Baseline (pre-booster), 28 days, 6 and 12 months post booster vaccination
Frequency of Cytokine-expressing T Cells
Frequency of wild-type SARS-CoV-2 spike-specific cytokine-expressing T cells will be assessed in a subset of participants (\~40%) using intracellular cytokine staining (ICS) by flow cytometry on PBMC samples. Results are reported as the frequency (%) of cytokine-expressing CD4 and CD8 memory T cells, summarised as geometric mean concentrations (GMCs) with 95% confidence intervals.
Time frame: Baseline (pre-booster), 28 days, 6 and 12 months post-booster vaccination
Cellular Immunity: Multiplex Cytokine Assays - Reported as Cytokine Concentrations in pg/ml and Presented as GMC and 95% CI
Wild-type SARS-CoV-2 spike-specific cytokine concentrations following PBMC stimulation will be assessed in a predefined subset of participants (approximately 40%) using multiplex cytokine assays. Cytokine concentrations will be reported in pg/mL and summarised as geometric mean concentrations (GMCs) with 95% confidence intervals. IFN-γ ELISpot, intracellular cytokine staining (flow cytometry), and multiplex cytokine assays will be performed on isolated peripheral blood mononuclear cells (PBMCs).
Time frame: Baseline (pre booster), 28 days-, 6 and 12 months post booster vaccination
Incidence of Unsolicited Adverse Events (AE)
All unsolicited AE will be collected for 28 days post booster vaccination. Data will be presented as proportion of participants who report unsolicited AE.
Time frame: 28 days-post booster vaccination
Incidence of Medically Attended Adverse Events
All participants with medically attended AE will be collected for 3 months post booster vaccination. Data will be presented as number of participants who report unsolicited AE.
Time frame: 3 months post booster vaccination
Incidence of Serious Adverse Events (SAE)
SAE will be collected throughout the follow-up period of 24 months post booster vaccination. Data will be presented as a proportion of participants who report unsolicited SAE.
Time frame: 24 months post-booster
Incidence of PCR Confirmed COVID-19 Infection
Confirmed SARS-CoV-2 infections will be documented throughout the follow-up period, by clinical severity.
Time frame: Up to 24 months post booster vaccination
Number of IFNγ Producing Cells/Million PBMCs
Applicable to the subset participants with additional blood collection. IFNγ producing cells as a measurement of cellular immunity will be assessed on a subset of the participants (40%) from each group. IFN-γ Enzyme-Linked ImmunoSpot (Elispot) assay will be performed on isolated peripheral blood mononuclear cells (PBMCs). Data will be reported as number of IFNγ producing cells/million and presented using means and 95% CI.
Time frame: At 18 and 24 months post booster vaccination
Frequency of Cytokine-expressing T Cells
Frequency of wild-type SARS-CoV-2 spike-specific cytokine-expressing T cells will be assessed in a subset of participants (\~40%) using intracellular cytokine staining (ICS) by flow cytometry on PBMC samples. Results are reported as the frequency (%) of cytokine-expressing CD4 and CD8 memory T cells, summarised as geometric mean concentrations (GMCs) with 95% confidence intervals.
Time frame: 18 and 24 months post-booster vaccination
Cellular Immunity: Multiplex Cytokine Assays - Reported as Cytokine Concentrations in pg/ml and Presented as GMC and 95% CI
Wild-type SARS-CoV-2 spike-specific cytokine concentrations following PBMC stimulation will be assessed in a predefined subset of participants (approximately 40%) using multiplex cytokine assays. Cytokine concentrations will be reported in pg/mL and summarised as geometric mean concentrations (GMCs) with 95% confidence intervals. IFN-γ ELISpot, intracellular cytokine staining (flow cytometry), and multiplex cytokine assays will be performed on isolated peripheral blood mononuclear cells (PBMCs).
Time frame: 18 and 24 months post booster vaccination
| Milestone | Standard | Fractional |
|---|---|---|
| Started | 300 | 301 |
| Received allocated d dose | 299 | 299 |
| Included in day 28 immunogenicity analysis | 292 | 295 |
| Completed | 282 | 285 |
| Not completed | 18 | 16 |
Serum samples collected at 28-days post booster vaccination from all groups will be evaluated for SARS-CoV-2 specific IgG antibodies using IgG ELISA. The primary endpoint is the seroresponse rate at the Day-28 visit. The seroresponse rate at the individual level is defined as either a ≥4-fold rise in binding antibodies at the Day-28 visit compared to baseline (pre-vaccination) with a titre of \<200 BAU/ml, a ≥2-fold rise among participants with a baseline (pre-vaccination) titre of \>200 BAU/ml, or a ≥4-times the lower limit of detection if baseline levels are lower than the limit of detection.
| Participants | Standard | Fractional |
|---|---|---|
| Seroresponse | 253 | 250 |
Questionnaire to document solicited reactions is developed specifically for this study. Data will be reported as the proportion of participants who report grade 3 or 4 reactions by each intervention arm. Solicited reactions such as pain, tenderness, erythema/redness, induration, swelling, fever, nausea, vomiting, headache, fatigue/malaise, myalgia, arthralgia, diarrhea, enlarged lymph nodes will be collected from the participants 7 days post-vaccination.
| Participants | Standard | Fractional |
|---|---|---|
| Solicited Grade 3 or 4 Local or Systemic Reaction | 6 | 4 |
Serum samples collected at 28-days post booster vaccination from all groups will be evaluated for SARS-CoV-2 specific IgG antibodies using IgG ELISA. The primary endpoint is the seroresponse rate at the Day-28 visit. The seroresponse rate at the individual level is defined as either a ≥4-fold rise in binding antibodies at the Day-28 visit compared to baseline (pre-vaccination) with a titre of \<200 BAU/ml, a ≥2-fold rise among participants with a baseline (pre-vaccination) titre of \>200 BAU/ml, or a ≥4-times the lower limit of detection if baseline levels are lower than the limit of detection. Priming strata (previously COVID vaccination): AstraZeneca (ChAdOx1-S, or Vaxzevria®); Sinopharm (BBIBP-CorV®); Sputnik V (Gam-COVID-Vac®)
| Participants | AstraZeneca (ChAdOx1-S, or Vaxzevria®) - Standard Pfizer-BioNTech Booster Group | AstraZeneca (ChAdOx1-S, or Vaxzevria®) - Fractional Pfizer-BioNTech Booster Group | Sinopharm (BBIBP-CorV®)- Standard Pfizer-BioNTech Booster Group | Sinopharm (BBIBP-CorV®)- Fractional Pfizer-BioNTech Booster Group | Sputnik V (Gam-COVID-Vac®)- Standard Pfizer-BioNTech Booster Group | Sputnik V (Gam-COVID-Vac®)- Fractional Pfizer-BioNTech Booster Group |
|---|---|---|---|---|---|---|
| Seroresponse by Priming Vaccine Strata | 55 | 52 | 170 | 169 | 28 | 29 |
Serum samples collected at 28-days post booster vaccination from all groups will be evaluated for SARS-CoV-2 specific IgG antibodies using IgG ELISA.
| BAU/ml | Standard | Fractional |
|---|---|---|
| SARS-CoV-2 Specific IgG Antibodies at Day-28 | 4946 (4614 to 5302) | 4619 (4292 to 4970) |
Serum samples collected at 28-days post booster vaccination from all groups will be evaluated for SARS-CoV-2 specific IgG antibodies using IgG ELISA. Priming strata (previously COVID vaccination): AstraZeneca (ChAdOx1-S, or Vaxzevria®); Sinopharm (BBIBP-CorV®); Sputnik V (Gam-COVID-Vac®)
| BAU/ml | AstraZeneca (ChAdOx1-S, or Vaxzevria®) - Standard Pfizer-BioNTech Booster Group | AstraZeneca (ChAdOx1-S, or Vaxzevria®) - Fractional Pfizer-BioNTech Booster Group | Sinopharm (BBIBP-CorV®)- Standard Pfizer-BioNTech Booster Group | Sinopharm (BBIBP-CorV®)- Fractional Pfizer-BioNTech Booster Group | Sputnik V (Gam-COVID-Vac®)- Standard Pfizer-BioNTech Booster Group | Sputnik V (Gam-COVID-Vac®)- Fractional Pfizer-BioNTech Booster Group |
|---|---|---|---|---|---|---|
| SARS-CoV-2 Specific IgG Antibodies at Day-28 by Priming Vaccine Strata | 4394 (3863 to 4997) | 4167 (3550 to 4892) | 5109 (4678 to 5580) | 4970 (4541 to 5438) | 5160 (4128 to 6450) | 3662 (3016 to 4447) |
Serum samples collected at baseline (pre booster), 28 days, 6 months, 12 months, 18 months, and 24 months post booster vaccination from the study arms will be evaluated for SARS-CoV-2 specific IgG antibodies using the commercial Euroimmun S1 IgG ELISA. Data will be reported as binding antibody units (BAU)/mL and presented as geometric mean concentration (GMC) and 95% confidence intervals (CI).
| binding antibody units (BAU/mL) | Standard | Fractional |
|---|---|---|
| Baseline anti-spike IgG GMC (95% CI) | 969 (876 to 1072) | 929 (839 to 1029) |
| 28 days anti-spike IgG GMC (95% CI) | 4946 (4614 to 5302) | 4619 (4292 to 4970) |
| 6 months anti-spike IgG GMC (95% CI) | 2085 (1926 to 2256) | 2123 (1964 to 2296) |
| 12 months anti-spike IgG GMC (95% CI) | 2204 (2030 to 2393) | 2208 (2027 to 2404) |
| 18 months anti-spike IgG GMC (95% CI) | 1336 (1231 to 1450) | 1425 (1313 to 1546) |
| 24 months anti-spike IgG GMC (95% CI) | 1051 (973 to 1135) | 1107 (1021 to 1199) |
Serum samples collected at baseline (pre booster), 28 days-, 6- and 12-months post booster vaccination from all groups will be evaluated for SARS-CoV-2 specific neutralising antibodies using the GenScript® cPass surrogate virus neutralization test (sVNT) for both wild-type and Omicron variant. Neutralising antibody response will be reported as percentage (%) inhibition of receptor binding domain-angiotensin-converting enzyme 2 (RBD-ACE2) binding relative to a positive control.
| percentage (%) inhibition | Standard | Fractional |
|---|---|---|
| Baseline Wuhan-Hu-1 SARS-CoV-2 sVNT inhibition | 81 (76 to 85) | 81 (77 to 84) |
| 28 days Wuhan-Hu-1 SARS-CoV-2 sVNT inhibition | 81 (78 to 84) | 81 (78 to 84) |
| 6 months Wuhan-Hu-1 SARS-CoV-2 sVNT inhibition | 89 (88 to 91) | 89 (88 to 91) |
| 12 months Wuhan-Hu-1 SARS-CoV-2 sVNT inhibition | 89 (88 to 90) | 89 (87 to 90) |
| 18 months Wuhan-Hu-1 SARS-CoV-2 sVNT inhibition | 88 (87 to 90) | 88 (86 to 90) |
| 24 months Wuhan-Hu-1 SARS-CoV-2 sVNT inhibition | 88 (86 to 89) | 88 (86 to 90) |
| Baseline Omicron BA.1 SARS-CoV-2 sVNT inhibition | 52 (17 to 77) | 51 (18 to 76) |
| 28 days Omicron BA.1 SARS-CoV-2 sVNT inhibition | 82 (75 to 85) | 81 (75 to 84) |
| 6 months Omicron BA.1 SARS-CoV-2 sVNT inhibition | 74 (46 to 87) | 77 (48 to 87) |
| 12 months Omicron BA.1 SARS-CoV-2 sVNT inhibition | 76 (44 to 87) | 79 (40 to 87) |
| 18 months Omicron BA.1 SARS-CoV-2 sVNT inhibition | 81 (61 to 86) | 81 (64 to 86) |
| 24 months Omicron BA.1 SARS-CoV-2 sVNT inhibition | 84 (71 to 88) | 85 (70 to 88) |
A subset of samples (20%) from all four timepoints will be assessed using a SARS-CoV-2 microneutralisation assay to both the wild type (vaccine) strain and for two SARS-CoV-2 Variants of concern. Neutralizing antibody will be reported as endpoint titre.
Results for this outcome have not been posted.
IFN-γ concentrations (IU/mL) as a measure of cellular immunity will be assessed in a subset of participants. IFN-γ production will be stimulated using QuantiFERON Human IFN-γ SARS-CoV-2 (Qiagen) and quantified by ELISA. Results are summarised as geometric mean concentrations (GMCs) with 95% confidence intervals.
| IU/mL | Standard Pfizer-BioNTech Booster Group | Fractional Pfizer-BioNTech Booster Group |
|---|---|---|
| Baseline IFN-γ Ag1 | 0.26 (0.20 to 0.34) | 0.31 (0.23 to 0.41) |
| 28 day IFN-γ Ag1 | 0.46 (0.37 to 0.58) | 0.60 (0.47 to 0.77) |
| 6 month IFN-γ Ag1 | 0.27 (0.21 to 0.34) | 0.33 (0.26 to 0.42) |
| 12 month IFN-γ Ag1 | 0.28 (0.22 to 0.36) | 0.30 (0.23 to 0.39) |
| 18 month IFN-γ Ag1 | 0.21 (0.15 to 0.28) | 0.28 (0.21 to 0.37) |
| 24 month IFN-γ Ag1 | 0.27 (0.20 to 0.37) | 0.35 (0.28 to 0.46) |
| Baseline IFN-γ Ag2 | 0.32 (0.24 to 0.41) | 0.38 (0.30 to 0.49) |
| 28 day IFN-γ Ag2 | 0.64 (0.51 to 0.79) | 0.75 (0.60 to 0.94) |
| 6 month IFN-γ Ag2 | 0.34 (0.27 to 0.42) | 0.42 (0.33 to 0.54) |
| 12 month IFN-γ Ag2 | 0.44 (0.34 to 0.57) | 0.59 (0.47 to 0.73) |
| 18 month IFN-γ Ag2 | 0.42 (0.32 to 0.55) | 0.49 (0.38 to 0.64) |
| 24 month IFN-γ Ag2 | 0.34 (0.26 to 0.45) | 0.42 (0.33 to 0.54) |
Applicable to the subset participants with additional blood collection. IFNγ producing cells as a measurement of cellular immunity will be assessed on a subset of the participants (40%) from each group. IFN-γ Enzyme-Linked ImmunoSpot (Elispot) assay will be performed on isolated peripheral blood mononuclear cells (PBMCs). Data will be reported as number of IFNγ producing cells/million and presented using means and 95% CI.
| IFN-γ SFU per 10⁶ cells | Standard Pfizer-BioNTech Booster Group | Fractional Pfizer-BioNTech Booster Group |
|---|---|---|
| Baseline | 43 (24 to 77) | 40 (21 to 75) |
| 28 days | 118 (77 to 181) | 127 (87 to 185) |
| 6 months | 88 (50 to 156) | 80 (43 to 147) |
| 12 months | 86 (50 to 147) | 82 (48 to 141) |
Frequency of wild-type SARS-CoV-2 spike-specific cytokine-expressing T cells will be assessed in a subset of participants (\~40%) using intracellular cytokine staining (ICS) by flow cytometry on PBMC samples. Results are reported as the frequency (%) of cytokine-expressing CD4 and CD8 memory T cells, summarised as geometric mean concentrations (GMCs) with 95% confidence intervals.
| % of cytokine-expressing T cells | Standard | Fractional |
|---|---|---|
| Baseline | 0.007 (0.004 to 0.013) | 0.008 (0.005 to 0.015) |
| 28 days | 0.014 (0.008 to 0.026) | 0.015 (0.008 to 0.027) |
| 6 months | 0.010 (0.006 to 0.019) | 0.011 (0.006 to 0.020) |
| 12 months | 0.019 (0.011 to 0.033) | 0.010 (0.006 to 0.019) |
Wild-type SARS-CoV-2 spike-specific cytokine concentrations following PBMC stimulation will be assessed in a predefined subset of participants (approximately 40%) using multiplex cytokine assays. Cytokine concentrations will be reported in pg/mL and summarised as geometric mean concentrations (GMCs) with 95% confidence intervals. IFN-γ ELISpot, intracellular cytokine staining (flow cytometry), and multiplex cytokine assays will be performed on isolated peripheral blood mononuclear cells (PBMCs).
| pg/mL | Standard Pfizer-BioNTech Booster Group | Fractional Pfizer-BioNTech Booster Group |
|---|---|---|
| Baseline | 2.77 (1.54 to 4.98) | 3.64 (2.15 to 6.16) |
| 28 days | 11.71 (7.45 to 18.39) | 14.74 (9.30 to 23.35) |
| 6 months | 4.38 (2.30 to 8.35) | 6.22 (3.43 to 11.29) |
| 12 months | 7.61 (4.40 to 13.16) | 10.71 (6.69 to 17.14) |
All unsolicited AE will be collected for 28 days post booster vaccination. Data will be presented as proportion of participants who report unsolicited AE.
| Participants | Standard Pfizer-BioNTech Booster Group- AstraZeneca | Fractional Pfizer-BioNTech Booster Group- AstraZeneca | Standard Pfizer-BioNTech Booster Group- Sinopharm | Fractional Pfizer-BioNTech Booster Group- Sinopharm | Standard Pfizer-BioNTech Booster Group-Sputnik | Fractional Pfizer-BioNTech Booster Group- Sputnik |
|---|---|---|---|---|---|---|
| Incidence of Unsolicited Adverse Events (AE) | 5 | 9 | 12 | 7 | 5 | 5 |
All participants with medically attended AE will be collected for 3 months post booster vaccination. Data will be presented as number of participants who report unsolicited AE.
| Participants | Standard | Fractional |
|---|---|---|
| Incidence of Medically Attended Adverse Events | 19 | 16 |
SAE will be collected throughout the follow-up period of 24 months post booster vaccination. Data will be presented as a proportion of participants who report unsolicited SAE.
| Participants | Standard Pfizer-BioNTech Booster Group- AstraZeneca | Fractional Pfizer-BioNTech Booster Group- AstraZeneca | Standard Pfizer-BioNTech Booster Group- Sinopharm | Fractional Pfizer-BioNTech Booster Group- Sinopharm | Standard Pfizer-BioNTech Booster Group- Sputnik | Fractional Pfizer-BioNTech Booster Group- Sputnik |
|---|---|---|---|---|---|---|
| Incidence of Serious Adverse Events (SAE) | 6 | 6 | 17 | 17 | 4 | 3 |
Confirmed SARS-CoV-2 infections will be documented throughout the follow-up period, by clinical severity.
| Participants | Standard | Fractional |
|---|---|---|
| Incidence of PCR Confirmed COVID-19 Infection | 14 | 14 |
Applicable to the subset participants with additional blood collection. IFNγ producing cells as a measurement of cellular immunity will be assessed on a subset of the participants (40%) from each group. IFN-γ Enzyme-Linked ImmunoSpot (Elispot) assay will be performed on isolated peripheral blood mononuclear cells (PBMCs). Data will be reported as number of IFNγ producing cells/million and presented using means and 95% CI.
Results for this outcome have not been posted.
Frequency of wild-type SARS-CoV-2 spike-specific cytokine-expressing T cells will be assessed in a subset of participants (\~40%) using intracellular cytokine staining (ICS) by flow cytometry on PBMC samples. Results are reported as the frequency (%) of cytokine-expressing CD4 and CD8 memory T cells, summarised as geometric mean concentrations (GMCs) with 95% confidence intervals.
Results for this outcome have not been posted.
Wild-type SARS-CoV-2 spike-specific cytokine concentrations following PBMC stimulation will be assessed in a predefined subset of participants (approximately 40%) using multiplex cytokine assays. Cytokine concentrations will be reported in pg/mL and summarised as geometric mean concentrations (GMCs) with 95% confidence intervals. IFN-γ ELISpot, intracellular cytokine staining (flow cytometry), and multiplex cytokine assays will be performed on isolated peripheral blood mononuclear cells (PBMCs).
Results for this outcome have not been posted.
Collected over Solicited local and systemic adverse events (AEs) were collected from the participants 7 days post-vaccination Unsolicited AEs up to 28 days following vaccination observed by the Investigator or reported by the participant, whether or not attributed to study medication, were also collected. Serious adverse events (SAE's) will be followed up for the duration of the trial up to 24 months.. Non-serious events are listed at a 0% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| Standard Pfizer-BioNTech Booster Group- AstraZeneca | 0/65 (0%) | 0/65 (0%) | 5/65 (7.7%) |
| Fractional Pfizer-BioNTech Booster Group- AstraZeneca | 0/65 (0%) | 2/65 (3.1%) | 7/65 (10.8%) |
| Standard Pfizer-BioNTech Booster Group- Sinopharm | 0/201 (0%) | 2/201 (1%) | 10/201 (5%) |
| Fractional Pfizer-BioNTech Booster Group- Sinopharm | 0/200 (0%) | 0/200 (0%) | 7/200 (3.5%) |
| Standard Pfizer-BioNTech Booster Group- Sputnik | 0/34 (0%) | 1/34 (2.9%) | 5/34 (14.7%) |
| Fractional Pfizer-BioNTech Booster Group- Sputnik | 0/36 (0%) | 0/36 (0%) | 5/36 (13.9%) |
| Event | Standard Pfizer-BioNTech Booster Group- AstraZeneca | Fractional Pfizer-BioNTech Booster Group- AstraZeneca | Standard Pfizer-BioNTech Booster Group- Sinopharm | Fractional Pfizer-BioNTech Booster Group- Sinopharm | Standard Pfizer-BioNTech Booster Group- Sputnik | Fractional Pfizer-BioNTech Booster Group- Sputnik |
|---|---|---|---|---|---|---|
| HepatobiliaryHepatobiliary disorders | 0/65 | 1/65 | 0/201 | 0/200 | 1/34 | 0/36 |
| GoutMetabolism and nutrition disorders | 0/65 | 1/65 | 0/201 | 0/200 | 0/34 | 0/36 |
| Lower limb fractureInjury, poisoning and procedural complications | 0/65 | 0/65 | 1/201 | 0/200 | 0/34 | 0/36 |
| Diabetes mellitusMetabolism and nutrition disorders | 0/65 | 0/65 | 1/201 | 0/200 | 0/34 | 0/36 |
| Event | Standard Pfizer-BioNTech Booster Group- AstraZeneca | Fractional Pfizer-BioNTech Booster Group- AstraZeneca | Standard Pfizer-BioNTech Booster Group- Sinopharm | Fractional Pfizer-BioNTech Booster Group- Sinopharm | Standard Pfizer-BioNTech Booster Group- Sputnik | Fractional Pfizer-BioNTech Booster Group- Sputnik |
|---|---|---|---|---|---|---|
| HypertensionVascular disorders | 0/65 | 1/65 | 1/201 | 0/200 | 2/34 | 1/36 |
| HeadacheNervous system disorders | 2/65 | 0/65 | 2/201 | 2/200 | 1/34 | 1/36 |
| Acute upper respiratory tract infectionInfections and infestations | 0/65 | 0/65 | 0/201 | 0/200 | 1/34 | 1/36 |
| Natural menopauseSocial circumstances | 0/65 | 0/65 | 0/201 | 0/200 | 1/34 | 0/36 |
| Acute respiratory tract infectionInfections and infestations | 0/65 | 1/65 | 1/201 | 0/200 | 0/34 | 1/36 |
| PalpitationsCardiac disorders | 0/65 | 0/65 | 0/201 | 0/200 | 0/34 | 1/36 |
| Abdominal crampsGastrointestinal disorders | 1/65 | 0/65 | 0/201 | 0/200 | 0/34 | 0/36 |
| AnaemiaBlood and lymphatic system disorders | 0/65 | 1/65 | 0/201 | 0/200 | 0/34 | 0/36 |
| ArthralgiaMusculoskeletal and connective tissue disorders | 1/65 | 0/65 | 0/201 | 1/200 | 0/34 | 0/36 |
| Back painMusculoskeletal and connective tissue disorders | 0/65 | 1/65 | 1/201 | 0/200 | 0/34 | 0/36 |
| Age, Categorical(Participants) | AstraZeneca (ChAdOx1-S, or Vaxzevria®) - Standard Pfizer-BioNTech Booster Group | AstraZeneca (ChAdOx1-S, or Vaxzevria®) - Fractional Pfizer-BioNTech Booster Group | Sinopharm (BBIBP-CorV®)- Standard Pfizer-BioNTech Booster Group | Sinopharm (BBIBP-CorV®)- Fractional Pfizer-BioNTech Booster Group | Sputnik V (Gam-COVID-Vac®)- Standard Pfizer-BioNTech Booster Group | Sputnik V (Gam-COVID-Vac®)- Fractional Pfizer-BioNTech Booster Group | Total |
|---|---|---|---|---|---|---|---|
| <=18 years | 0 | 0 | 3 | 0 | 0 | 0 | 3 |
| Between 18 and 65 years | 65 | 65 | 189 | 186 | 30 | 35 | 570 |
| >=65 years | 0 | 0 | 9 | 14 | 4 | 1 | 28 |
| Age, Continuous(years) | AstraZeneca (ChAdOx1-S, or Vaxzevria®) - Standard Pfizer-BioNTech Booster Group | AstraZeneca (ChAdOx1-S, or Vaxzevria®) - Fractional Pfizer-BioNTech Booster Group | Sinopharm (BBIBP-CorV®)- Standard Pfizer-BioNTech Booster Group | Sinopharm (BBIBP-CorV®)- Fractional Pfizer-BioNTech Booster Group | Sputnik V (Gam-COVID-Vac®)- Standard Pfizer-BioNTech Booster Group | Sputnik V (Gam-COVID-Vac®)- Fractional Pfizer-BioNTech Booster Group | Total |
|---|---|---|---|---|---|---|---|
| Median | 34.5 (32.2 to 45.8) | 40.2 (33.7 to 49.6) | 47.8 (31.4 to 57.7) | 48.8 (32 to 56.9) | 43.1 (32.1 to 52.7) | 41.3 (34.7 to 50.3) | 44 (32.4 to 54.7) |
| Sex: Female, Male(Participants) | AstraZeneca (ChAdOx1-S, or Vaxzevria®) - Standard Pfizer-BioNTech Booster Group | AstraZeneca (ChAdOx1-S, or Vaxzevria®) - Fractional Pfizer-BioNTech Booster Group | Sinopharm (BBIBP-CorV®)- Standard Pfizer-BioNTech Booster Group | Sinopharm (BBIBP-CorV®)- Fractional Pfizer-BioNTech Booster Group | Sputnik V (Gam-COVID-Vac®)- Standard Pfizer-BioNTech Booster Group | Sputnik V (Gam-COVID-Vac®)- Fractional Pfizer-BioNTech Booster Group | Total |
|---|---|---|---|---|---|---|---|
| Female | 33 | 32 | 115 | 114 | 19 | 14 | 327 |
| Male | 32 | 33 | 86 | 86 | 15 | 22 | 274 |
| Race and Ethnicity Not Collected(Participants) | AstraZeneca (ChAdOx1-S, or Vaxzevria®) - Standard Pfizer-BioNTech Booster Group | AstraZeneca (ChAdOx1-S, or Vaxzevria®) - Fractional Pfizer-BioNTech Booster Group | Sinopharm (BBIBP-CorV®)- Standard Pfizer-BioNTech Booster Group | Sinopharm (BBIBP-CorV®)- Fractional Pfizer-BioNTech Booster Group | Sputnik V (Gam-COVID-Vac®)- Standard Pfizer-BioNTech Booster Group | Sputnik V (Gam-COVID-Vac®)- Fractional Pfizer-BioNTech Booster Group | Total |
|---|---|---|---|---|---|---|---|
| Count of participants | — | — | — | — | — | — | 0 |
| Region of Enrollment(participants) | AstraZeneca (ChAdOx1-S, or Vaxzevria®) - Standard Pfizer-BioNTech Booster Group | AstraZeneca (ChAdOx1-S, or Vaxzevria®) - Fractional Pfizer-BioNTech Booster Group | Sinopharm (BBIBP-CorV®)- Standard Pfizer-BioNTech Booster Group | Sinopharm (BBIBP-CorV®)- Fractional Pfizer-BioNTech Booster Group | Sputnik V (Gam-COVID-Vac®)- Standard Pfizer-BioNTech Booster Group | Sputnik V (Gam-COVID-Vac®)- Fractional Pfizer-BioNTech Booster Group | Total |
|---|---|---|---|---|---|---|---|
| Mongolia | 65 | 65 | 201 | 200 | 34 | 36 | 601 |
| BMI(kg/m2) | AstraZeneca (ChAdOx1-S, or Vaxzevria®) - Standard Pfizer-BioNTech Booster Group | AstraZeneca (ChAdOx1-S, or Vaxzevria®) - Fractional Pfizer-BioNTech Booster Group | Sinopharm (BBIBP-CorV®)- Standard Pfizer-BioNTech Booster Group | Sinopharm (BBIBP-CorV®)- Fractional Pfizer-BioNTech Booster Group | Sputnik V (Gam-COVID-Vac®)- Standard Pfizer-BioNTech Booster Group | Sputnik V (Gam-COVID-Vac®)- Fractional Pfizer-BioNTech Booster Group | Total |
|---|---|---|---|---|---|---|---|
| Number | 26.3 | 25.4 | 24.6 | 24.8 | 25.3 | 25.8 | 25.2 |
PDFs hosted by the registry, ClinicalTrials.gov.
Plan to share: Yes — We will share de-identified data to ethically approved studies in cases where participants have indicated on the consent form that they consent to the use of their data and where consistent with terms of collaboration agreements.
Supporting information: Study protocol, Informed consent form
Time frame: Individual participant data (IPD) sharing plans in development
Access criteria: IPD sharing plans in development
Data sharing details ↗ · www.mcri.edu.au
This study is completed, as verified in Mar 2026. You cannot join it, but the record below documents what was studied.
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Studies of the drug tested here: BNT162 Vaccine
Murdoch Childrens Research Institute