The £7 million study - led by Oxford Uni - will be the first to determine the effects of using different vaccines.
The Government funded study will determine whether using different coronavirus vaccines for the first and second dose is safe and effective.
The study, dubbed Com-Cov, will initially look at mixing doses of the Oxford University/AstraZeneca and Pfizer/BioNTech vaccines, but researchers said more will be added to the list.
The University of Oxford will lead the first trial of the study, testing eight different combinations with dosing regimens that are either 12 weeks or 28 days apart.
Those aged 50 and over are being called on to take part in the research, with over 800 patients expected to be involved.
They will be recruited over the course of February through the NHS Covid-19 Vaccine Research Registry, with initial results expected to become available during the summer.
Matthew Snape, Associate Professor in Paediatrics and Vaccinology at the University of Oxford, and Chief Investigator on the trial said: "If we do show that these vaccines can be used interchangeably in the same schedule this will greatly increase the flexibility of vaccine delivery, and could provide clues as to how to increase the breadth of protection against new virus strains."
Using blood samples collected from the trial volunteers, the study will monitor the impact of the different dosing regimens on participants' immune responses and for any additional adverse reactions to the new combinations of vaccines.
Professor Snape continued: "This is a tremendously exciting study that will provide information vital to the roll out of vaccines in the UK and globally. We call on those aged 50 years and above who have not yet received a COVID-19 vaccine to visit the website to find out more about the study and see if there is a study site near them."
We're pleased to announce a trial to explore alternating different #COVID-19 vaccines, to explore the potential for flexibility in delivery and look for clues as to how to increase the breadth of protection against new virus strains.— University of Oxford (@UniofOxford) February 4, 2021
Find out more>>https://t.co/QT4n6Uz7v2
If the study shows promising results, the MHRA would formally assess the safety and efficacy of any new vaccination regimen before it would be rolled out to patients.
Deputy chief medical officer and senior responsible officer for the study, Professor Jonathan Van-Tam, said: “Given the inevitable challenges of immunising large numbers of the population against Covid-19 and potential global supply constraints, there are definite advantages to having data that could support a more flexible immunisation programme, if needed and if approved by the medicines regulator.
“It is also even possible that by combining vaccines, the immune response could be enhanced giving even higher antibody levels that last longer; unless this is evaluated in a clinical trial we just won’t know.
“This study will give us greater insight into how we can use vaccines to stay on top of this nasty disease.”
The study is being run by the National Immunisation Schedule Evaluation Consortium (NISEC) across eight different sites across England – in the likes of London, Oxford, Southampton, Birmingham, Bristol, Nottingham and Liverpool.