Major trial launches for oxford COVID-19 vaccine
NCT ID NCT04400838
First seen Jun 26, 2026 · Last updated Jun 26, 2026
Summary
This large study tested the Oxford-AstraZeneca COVID-19 vaccine (ChAdOx1 nCoV-19) in over 10,000 healthy UK adults aged 18 and older. The goal was to see if the vaccine safely prevents symptomatic COVID-19. Participants received either the vaccine or a control shot, and researchers tracked cases and side effects.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- ChAdOx1 nCoV-19 (Oxford-AstraZeneca COVID-19 vaccine)
- What this could lead to
- If successful, this vaccine could help protect people from COVID-19, reducing illness and spread of the virus.
- What could go wrong
- This is an early combined phase 2/3 trial, so results may not confirm long-term protection or safety for all populations. Side effects like fever or fatigue are possible.
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
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Phase 2/3
Runs two stages together: whether the treatment works, then large-scale confirmation.
- Participants
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10,811 people
The number who actually took part.
- Started
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May 2020
- Finished
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Feb 2025
- Lead sponsor
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Other sponsor
The registry's catch-all category, for sponsors it does not file as a company, a government agency, or a research network.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
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18 years and older
- Sex
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Anyone
- Healthy volunteers
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Accepted
You do not need to have the condition being studied to take part.
Show the full entry requirements Hide 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: * Adults aged 18 - 55 years (groups 4, 5, 6 and 11) * Adults aged 56-69 years (groups 1, 7, and 9) * Adults aged 70 years and older (groups 2, 8, and 10) * Able and willing (in the Investigator's opinion) to comply with all study requirements. * Willing to allow the investigators to discuss the volunteer's medical history with their General Practitioner and access all medical records when relevant to study procedures. * For females of childbearing potential only, willingness to practice continuous effective contraception (see below) during the study and a negative pregnancy test on the day(s) of screening and vaccination. * Agreement to refrain from blood donation during the course of the study. * Provide written informed consent. Additional Inclusion criteria to Group 12 (HIV sub-study): * HIV positive * Receiving antiretroviral therapy * Undetectable HIV viral load * CD4\>350 cells/mL Exclusion Criteria: • Participation in COVID-19 prophylactic drug trials for the duration of the study. Note: Participation in COVID-19 treatment trials is allowed in the event of hospitalisation due to COVID-19. The COV002 study team should be informed as soon as possible. • Participation in SARS-CoV-2 serological surveys where participants are informed of their serostatus for the duration of the study. Note: Disclosure of serostatus post enrolment may accidently unblind participants to group allocation. Participation in COV002 can only be allowed if volunteers are kept blinded to their serology results from local/national serological surveys * Receipt of any vaccine (licensed or investigational) other than the study intervention within 30 days before and after each study vaccination, with the exception of the licensed seasonal influenza vaccination and the licensed pneumococcal vaccination. Participants will be encouraged to receive these vaccinations at least 7 days before or after their study vaccine. * Prior or planned receipt of an investigational or licensed vaccine or product likely to impact on interpretation of the trial data (e.g. Adenovirus vectored vaccines, any coronavirus vaccines). This exclusion criteria will not apply to group 11, as recruitment will be targeted at those volunteers who previously received a ChAdOx1 vectored vaccine. * Administration of immunoglobulins and/or any blood products within the three months preceding the planned administration of the vaccine candidate. * Any confirmed or suspected immunosuppressive or immunodeficient state (except group 12, where HIV infected participants are allowed); asplenia; recurrent severe infections and use of immunosuppressant medication within the past 6 months, except topical steroids or short-term oral steroids (course lasting ≤14 days) * History of allergic disease or reactions likely to be exacerbated by any component of ChAdOx1 nCoV-19 or MenACWY * Any history of angioedema. * Any history of anaphylaxis. * Pregnancy, lactation or willingness/intention to become pregnant during the study. * Current diagnosis of or treatment for cancer (except basal cell carcinoma of the skin and cervical carcinoma in situ). * History of serious psychiatric condition likely to affect participation in the study. * Bleeding disorder (e.g. factor deficiency, coagulopathy or platelet disorder), or prior history of significant bleeding or bruising following IM injections or venepuncture. * Continuous use of anticoagulants, such as coumarins and related anticoagulants (i.e. warfarin) or novel oral anticoagulants (i.e. apixaban, rivaroxaban, dabigatran and edoxaban) * Suspected or known current alcohol or drug dependency. * Any other significant disease, disorder or finding which may significantly increase the risk to the volunteer because of participation in the study, affect the ability of the volunteer to participate in the study or impair interpretation of the study data. * Severe and/or uncontrolled cardiovascular disease, respiratory disease, gastrointestinal disease, liver disease, renal disease, endocrine disorder and neurological illness (mild/moderate well controlled comorbidities are allowed) * History of laboratory confirmed COVID-19 (except groups 5d, 5e, 5f, 9, 10 and 11). * Seropositivity to SARS-CoV-2 before enrolment (except groups 5d, 5e, 5f, 9, 10 and 11) * NB: volunteers with previous NAAT positive results are also allowed in groups 9, 10 and 11 Additional Exclusion criteria to Groups 4, 6, 9 and 10 * History of allergic disease or reactions likely to be exacerbated by Paracetamol * Note: Caution should be taken when recommending paracetamol to adults who already take paracetamol chronically Re-vaccination exclusion criteria (two-dose groups only) * Anaphylactic reaction following administration of vaccine * Pregnancy. An exception to this will be prior to receipt of a booster dose at extra visit B. If a pregnant woman has discussed vaccination with their usual clinician (e.g. GP) and chooses to receive a COVID-19 vaccination, this may be administered by the trial team as part of extra visit B. (Protocol 19.0) or as part of the provision of treatment to controls. * Any AE that in the opinion of the Investigator may affect the safety of the participant or the interpretation of the study results
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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
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CCVTM, University of Oxford, Churchill Hospital
Oxford, OX3 7LE, United Kingdom
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Castle Hill Hospital
Cottingham, Hull, HU16 5JQ, United Kingdom
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Glasgow University and NHS Greater Glasgow & Clyde, New Lister Building, Glasgow Royal Infirmary & Queen Elizabeth University Hospital
Glasgow, G31 2ER, United Kingdom
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Guy's and St Thomas' NHS Foundation Trust, Department of Infection, St Thomas Hospital
London, SE1 7EH, United Kingdom
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Imperial College Healthcare NHS Trust
London, W12 0HS, United Kingdom
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John Radcliffe Hospital
Oxford, OX3 9DU, United Kingdom
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Liverpool School of Tropical Medicine (LSTM), Accelerator Research Clinic. Clinical Sciences Accelerator
Liverpool, L7 8XZ, United Kingdom
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London North West University Healthcare Trust (LNWUH), Northwick Park Hospital
London, HA1 3UJ, United Kingdom
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NHS Lothian, Western General Hospital
Edinburgh, EH4 2XU, United Kingdom
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NIHR Cambridge Clinical Research Facility
Cambridge, CB2 0QQ, United Kingdom
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North Bristol NHS Trust
Bristol, United Kingdom
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Public Health Wales
Newport, NP18 3XQ, United Kingdom
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Sheffield Teaching Hospitals, Royal Hallamshire Hospital
Sheffield, S10 2RX, United Kingdom
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St Georges University Hospital NHS Foundation Trust
London, Tooting, SW17 0QT, United Kingdom
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The Newcastle upon Tyne Hospitals NHS Foundation Trust, Royal Victoria Infirmary
Newcastle upon Tyne, NE1 4LP, United Kingdom
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University College London Hospitals NHS Foundation Trust
London, NW1 2PG, United Kingdom
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University Hospital Southampton NHS Foundation Trust
Southampton, Hampshire, SO16 6YD, United Kingdom
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University Hospitals Birmingham NHS Foundation Trust
Birmingham, United Kingdom
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University Hospitals Bristol and Weston NHS Foundation Trust
Bristol, BS1 3NU, United Kingdom
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University of Nottingham Health Service, Cripps Health Centre, University Park
Nottingham, NG7 2QW, United Kingdom
More trials for these conditions
Other studies related to the condition(s) this trial covers.
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- Scientists create COVID-19 biobank to unlock disease secrets
- Placenta cells tested as COVID fighter – but trial stopped early
- Plasma from COVID-19 survivors tested as treatment for the critically ill
- Study tracks virus shedding in COVID-19 contacts
- Could a simple breath test replace nasal swabs for COVID-19?