New Self-Amplifying RNA vaccine shows promise in massive COVID-19 trial

NCT ID NCT05012943

What the study statuses mean

This study's is highlighted.

Recruitment status, easiest to join first

Recruiting now
This trial is taking on new participants right now.
Not yet recruiting
Registered, but not yet taking participants.
By invitation only
Not open to general applications. Only people the study team invites can take part.
Paused
Paused for now. It may or may not start again.
Ongoing
Running, but no longer taking on new participants.
Completed This study
The trial has finished. Results may not be published yet.
Stopped early
Stopped early, before it reached the end. That can be for many reasons, including safety.
Cancelled
Cancelled before anyone took part.

Expanded access (not trials)

Expanded access
Not a trial. This treatment can be requested outside a study, case by case, for people who qualify.
Expanded access (paused)
Not a trial. The treatment can normally be requested outside a study, but is unavailable right now.
Expanded access (ended)
Not a trial. The treatment could once be requested outside a study, but no longer can.
Approved
The treatment has been approved, so it is available normally rather than through this programme.

When the status isn't known

Details not published
The full record has not been published yet, so there is little to show here.
Status unknown
This status has not been confirmed recently, so it may be out of date.

First seen Jun 27, 2026 · Last updated Jun 27, 2026

Summary

This study tested a new type of COVID-19 vaccine called ARCT-154, which uses self-amplifying RNA technology to potentially provide stronger protection. Nearly 20,000 adults in Vietnam, including those with health conditions, received the vaccine or a placebo. Researchers measured safety, immune responses, and how well the vaccine prevented COVID-19.

This is an AI summary of the original study and may miss details. Read our disclaimer.

Study facts

What this study's own registry entry says, in plain language.

Phase

Phase 2/3

Runs two stages together: whether the treatment works, then large-scale confirmation.

Participants

19,474 people

The number who actually took part.

Started

Aug 2021

Finished

Jan 2023

Lead sponsor

A company

The lead sponsor is a pharmaceutical, biotech, or medical-device company.

Who can take part

This study's own entry requirements. Only the study team can say for certain whether you qualify.

Ages

18 to 100 years

Sex

Anyone

Healthy volunteers

Accepted

You do not need to have the condition being studied to take part.

Show the full entry requirements

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: Individuals who: 1. are able to provide consent 2. agree to comply with all study visits and procedures 3. are of childbearing potential and sexually active must be willing to adhere to contraceptive requirements 4. are male or female ≥18 years of age (or, for Phase 1, 18 to \< 60 years of age) 5. are at higher risk of developing COVID-19 based on where they work or live Exclusion Criteria: Individuals who: 1. Significant infection or other acute illness, including body temperature \>100.4°F (\>38.0°C) on the day prior to or Day 1. Participants meeting this criterion may be rescheduled within the relevant window periods. Afebrile participants with minor illnesses can be enrolled at the discretion of the investigator. 2. Pregnant or breastfeeding. 3. Known history of COVID-19 (asymptomatic SARS-CoV-2 infection and/or nucleocapsid positive test is not exclusionary). 4. Close contact with a person known to be SARS-CoV-2 positive or with a clinical diagnosis of COVID-19 within 7 days prior to enrollment. Participants meeting this criterion who remain asymptomatic for 7 days may be rescheduled for enrollment within the relevant windows. 5. Known history of anaphylaxis, urticaria, or other significant adverse reaction to the vaccine or its excipients. 6. Known history of anaphylaxis to other vaccines. 7. Bleeding disorder considered a contraindication to intramuscular (IM) injection or phlebotomy. 8. Immunosuppressive or immunodeficient state, asplenia, recurrent severe infections, or known to be HIV positive. 9. An underlying clinically significant acute or chronic medical condition or physical examination findings for which, in the opinion of the investigator, participation would not be in the best interest of the participant (eg, compromise the well-being) or that could prevent, limit, or confound the protocol-specified assessments. Prior/Concomitant Therapy 10. Has previously received investigational or approved MERS-CoV, SARS-CoV, SARS-CoV-2 vaccines or who have plans to receive off-study COVID-19 vaccines. 11. Has received a live replicating vaccine within 28 days prior to each study vaccination or a licensed inactivated or non-replicating vaccine within 14 days prior to first study vaccination. 12. Has received treatment with immunosuppressive therapy, including cytotoxic agents or systemic corticosteroids, eg, for cancer or an autoimmune disease, within 6 months prior to Screening, or planned receipt throughout the study. If systemic corticosteroids have been administered short term (\<14 days) for treatment of an acute illness, participants should not be enrolled into the study until corticosteroid therapy has been discontinued for at least 28 days prior to first study vaccine administration. Inhaled/nebulized, intra-articular, intrabursal, or topical (skin or eyes) corticosteroids are permitted. 13. Has received systemic immunoglobulins or blood products within 3 months prior to first study vaccine administration or plans to receive such products during the study. Other Exclusions 14. Demonstrated inability to comply with the study procedures. 15. Investigator site staff members, employees of the Sponsor or the CRO directly involved in the conduct of the study, or site staff members otherwise supervised by the investigator, or immediate family members of any of the previously mentioned individuals. 16. Other restrictions apply to Phase 1 participants to ensure they are healthy. Additional Exclusion Criteria for Phase 3c Participants Only: No contraindications (as specified in the prescribing information) to receiving the ChAdOx1 vaccine.

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Conditions

The condition(s) this trial relates to.

As listed by the trial registrant

The condition terms exactly as the trial's registrant entered them.

Contacts and locations

Locations

  • Hanoi Medical University

    Hanoi, Hanoi, 00000, Vietnam

  • Military Medical University

    Hanoi, Hanoi, 00000, Vietnam

  • Pasteur Institute

    Ho Chi Minh City, Ho Chi Minh, 00000, Vietnam

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