ARCT-154 vs Placebo: Number of Participants With a First Occurrence of 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 | 0.0277 | 0.0243 | 0.0315 | wilson | ClinicalTrials.gov | |
| Risk in group 2 | 0.0617 | 0.0566 | 0.0671 | wilson | ClinicalTrials.gov | |
| Risk difference, group 1 minus group 2 | -0.034 | -0.0404 | -0.0277 | newcombe hybrid score | ClinicalTrials.gov | |
| Risk ratio, group 1 over group 2 | 0.449 | 0.384 | 0.524 | log | ClinicalTrials.gov | |
| Odds ratio, group 1 over group 2 | 0.433 | 0.369 | 0.509 | log | ClinicalTrials.gov | |
| Number needed to treat, for one fewer participant with the outcome on ARCT-154 than on Placebo | 29.4 | 24.8 | 36.2 | 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 Phase 3b. | 223 | 8,056 | 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 Phase 3b. | 496 | 8,044 | OG001 | ClinicalTrials.gov |
Outcome 5
| Field | Value | Source |
|---|---|---|
| Type | SECONDARY | ClinicalTrials.gov |
| Title | Number of Participants With a First Occurrence of COVID-19 | ClinicalTrials.gov |
| Description | Number of participants with a first occurrence of COVID-19 in participants with no evidence of prior infection. | ClinicalTrials.gov |
| Time frame | Day 1 to Day 92 | ClinicalTrials.gov |
| Population | Intent-to-Treat (ITT) Analysis Set, which included all participants who received any dose of study vaccine. Participants were analyzed according to the vaccine to which the participant was randomly assigned. As pre-specified, data are presented for participants in the Phase 3b ITT. | 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.