ARCT-154 vs Placebo: Number of Participants With a First Occurrence of Severe COVID-19
Calculated by ConductScience from the counts the trial posted to ClinicalTrials.gov.
Measures 6
Calculated by ConductScience from the counts the trial posted to ClinicalTrials.gov.
| Measure | Value | 95% interval, lower | 95% interval, upper | Method | Note | Source |
|---|---|---|---|---|---|---|
| Risk in group 1 | 0.000236 | 0.0000646 | 0.000858 | wilson | ClinicalTrials.gov | |
| Risk in group 2 | 0.00542 | 0.00402 | 0.00729 | wilson | ClinicalTrials.gov | |
| Risk difference, group 1 minus group 2 | -0.00518 | -0.00706 | -0.00365 | newcombe hybrid score | ClinicalTrials.gov | |
| Risk ratio, group 1 over group 2 | 0.0435 | 0.0105 | 0.179 | log | ClinicalTrials.gov | |
| Odds ratio, group 1 over group 2 | 0.0433 | 0.0105 | 0.179 | log | ClinicalTrials.gov | |
| Number needed to treat, for one fewer participant with the outcome on ARCT-154 than on Placebo | 193 | 142 | 274 | from the risk difference interval | ClinicalTrials.gov |
Groups 2
Group 2 names the comparator: placebo.
| Group | Title | Description | With the outcome | Analysed | ClinicalTrials.gov code | Source |
|---|---|---|---|---|---|---|
| Group 1 | ARCT-154 | This study was conducted in 3 phases (Phase 1, 2, 3a, 3b, 3c). Phase 1, 2, 3a, 3b: Participants were randomly assigned to receive up to 2 vaccination series at 28-day intervals: an initial vaccination series with vaccinations on Day 1 and Day 29 and an additional vaccination series on Day 92 and 120. Each participant received a two-dose vaccination series of ARCT-154 at a dose of 5 µg or a two-dose vaccination series of placebo (saline) in the first series. In the second vaccination series, participants in Phase 1 and 3b received a two-dose vaccination series with the opposite vaccine on Day 92 and 120 (Switchover vaccination series). Participants in Phase 2 and 3a who received 2 doses of ARCT-154 vaccine in the first vaccine series were re-randomized to receive either dose 3 of ARCT-154 on Day 92 plus placebo on Day 120 or placebo on Day 92 plus placebo on Day 120. Phase 3c: Participants were randomly assigned to a study group to receive two-dose vaccination series (Day 1 and Day 29) of ARCT-154 at a dose of 5 µg or approved COVID-19 vaccine comparator (Astra Zeneca's COVID-19 vaccine \[ChAdOx1 nCoV-19\]). In Phase 3c, participants received only 2 doses of their assigned treatment (no switchover) on Days 1 and 29. As pre-specified, data are presented pooled per treatment received. Data in this arm are presented pooled for ARCT-154 received in Phases 1, 2, 3a, 3b. | 2 | 8,492 | OG000 | ClinicalTrials.gov |
| Group 2 | Placebo | This study was conducted in 3 phases (Phase 1, 2, 3a, 3b, 3c). Phase 1, 2, 3a, 3b: Participants were randomly assigned to receive up to 2 vaccination series at 28-day intervals: an initial vaccination series with vaccinations on Day 1 and Day 29 and an additional vaccination series on Day 92 and 120. Each participant received a two-dose vaccination series of ARCT-154 at a dose of 5 micrograms (µg) or a two-dose vaccination series of placebo (saline) in the first series. In the second vaccination series, participants in Phase 1 and 3b received a two-dose vaccination series with the opposite vaccine on Day 92 and 120 (Switchover vaccination series). Participants in Phase 2 and 3a who received 2 doses of ARCT-154 vaccine in the first vaccine series were re-randomized to receive either dose 3 of ARCT-154 on Day 92 plus placebo on Day 120 or placebo on Day 92 plus placebo on Day 120. Phase 3c: Participants were randomly assigned to a study group to receive two-dose vaccination series of ARCT-154 at a dose of 5 µg or approved COVID-19 vaccine comparator (Astra Zeneca's COVID-19 vaccine \[ChAdOx1 nCoV-19). In Phase 3c, participants received only 2 doses of their assigned treatment (no switchover) on Days 1 and 29. As pre-specified, data are presented pooled per treatment received. Data in this arm are presented pooled for placebo received in Phases 1, 2, 3a, 3b. | 43 | 7,940 | OG001 | ClinicalTrials.gov |
Outcome 5
| Field | Value | Source |
|---|---|---|
| Type | SECONDARY | ClinicalTrials.gov |
| Title | Number of Participants With a First Occurrence of Severe COVID-19 | ClinicalTrials.gov |
| Description | Number of participants with a first occurrence of severe COVID-19 in participants with no evidence of prior infection. Severe COVID-19 was defined as a positive SARS-CoV-2 test, symptoms per protocol-defined COVID-19 and any of the following: Clinical signs at rest indicative of severe systemic illness: - Respiratory rate ≥30 per minute, - Heart rate ≥125 per minute, - Oxygen saturation (SpO2) ≤93% on room air at sea level or partial pressure of oxygen (PO2)/fraction of inspired oxygen (FiO2) \<300 millimeter of mercury (mm Hg) - Respiratory failure (defined as needing high flow oxygen, noninvasive ventilation, mechanical ventilation or extracorporeal membrane oxygenation \[ECMO\]); Evidence of shock: - Systolic blood pressure (SBP) \<90 mm Hg, or - Diastolic blood pressure (DBP) \<60 mm Hg, or requiring vasopressors, - Significant acute renal, hepatic, or neurologic dysfunction - Admission to an intensive care unit (ICU) - Death | ClinicalTrials.gov |
| Time frame | Day 36 to Day 92 | ClinicalTrials.gov |
| Population | Modified Intent-to-Treat (mITT) Analysis Set (pooled for Phases 1/2/3a/3b), which included all participants who received all protocol-required doses of study vaccine up to the evaluation timepoint concerned, and who had no evidence of SARS-CoV-2 infection on Day 1 or up to 7 days after the 2nd study vaccination. As pre-specified, data are presented pooled per treatment received for participants in Phases 1/2/3a/3b only. | ClinicalTrials.gov |
Trial 8
| Field | Value | Source |
|---|---|---|
| Title | The ARCT-154 Self-Amplifying RNA Vaccine Efficacy Study (ARCT-154-01) | ClinicalTrials.gov |
| NCT number | NCT05012943 | ClinicalTrials.gov |
| Phases | PHASE2, PHASE3 | ClinicalTrials.gov |
| Conditions | COVID-19 Vaccines | ClinicalTrials.gov |
| Interventions | ARCT-154 Self-Amplifying RNA SARS-CoV-2 Vaccine, Placebo (normal saline), Astra Zeneca COVID-19 vaccine | ClinicalTrials.gov |
| Lead sponsor | Vinbiocare Biotechnology Joint Stock Company | ClinicalTrials.gov |
| Results first posted | 2025-11-06 | ClinicalTrials.gov |
| Results on ClinicalTrials.gov | https://clinicaltrials.gov/study/NCT05012943?tab=results | ClinicalTrials.gov |
Source 4
| Field | Value | Source |
|---|---|---|
| Release | trial-comparisons-2026-03-23-0.1.0 | ClinicalTrials.gov |
| Release manifest SHA-256 | f66225897fbf258b57ea10bdacfd0347d3cdfda93f7f5685234b7e06ea36fa57 | ClinicalTrials.gov |
| AACT copy | 2026-03-23 | ClinicalTrials.gov |
| Tables read | outcome_counts.parquet, outcome_measurements.parquet, outcomes.parquet, reported_event_totals.parquet, reported_events.parquet, result_groups.parquet, studies.parquet, ctgov_trial.parquet | ClinicalTrials.gov |
Release trial-comparisons-2026-03-23-0.1.0
ClinicalTrials.gov's posted results, through CTTI's AACT: ClinicalTrials.gov data via Aggregate Analysis of ClinicalTrials.gov (AACT), CTTI. CTTI makes its materials freely available and requests acknowledgement. https://aact.ctti-clinicaltrials.org/documentation/299 ClinicalTrials.gov's data carry an international copyright outside the United States: https://clinicaltrials.gov/about-site/terms-conditions. The measures are ConductScience's calculation from them.
ClinicalTrials.gov: none stated ClinicalTrials.gov's data carry an international copyright outside the United States: https://clinicaltrials.gov/about-site/terms-conditions. The measures are ConductScience's calculation from them.