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World's first COVID-19 vaccine alternating dose study launched in Oxford

04/02/2021

This article is from 4 February 2021

The world's first COVID-19 vaccine study researching alternating doses and intervals of approved vaccines, has begun in Oxford.

The study, run at the University of Oxford's Centre for Clinical Vaccinology and Tropical Medicine at the Churchill Hospital, will determine the effects of using a different vaccine for the second dose to the first dose, in addition to two different intervals between doses.

The study, classified as an Urgent Public Health study by the National Institute for Health Research (NIHR), is being undertaken by the National Immunisation Schedule Evaluation Consortium (NISEC) and the Oxford Vaccine Group, and is backed by £7 million of government funding from the Vaccines Taskforce.

Over 800 volunteers aged 50 years old and above, including 100 in Oxford, are expected to take part in the study referred to as the COVID-19 Heterologous Prime Boost study, or 'Com-Cov', across eight NIHR-supported sites across England.

The study will look to gather more evidence on different intervals between the first and second dose for both a mixed-vaccine regimen and for when the same vaccine is used for both doses, as is currently implemented for the national COVID-19 vaccination programme.

The clinical study will monitor the impact of the different dosing regimens on patients' immune responses, and whether this can be a viable route to increase the flexibility of the UK's vaccination programme. It has received ethics approval, as well as approval from the Medicines and Healthcare products Regulatory Agency (MHRA) to commence.

Matthew Snape, Associate Professor in Paediatrics and Vaccinology at the University of Oxford, said:

"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 Com-Cov vaccine trial website to find out more about the study and see if there is a study site near them.

"If we do show that these vaccines can be interchangeable 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."

The study will have eight different arms, testing eight different combinations and interval doses:

  • Oxford/AstraZeneca and Oxford/AstraZeneca - 28 days apart
  • Oxford/AstraZeneca and Oxford/AstraZeneca - 12 weeks apart
  • Pfizer/BioNTech and Pfizer/BioNTech - 28 days apart
  • Pfizer/BioNTech and Pfizer/BioNTech - 12 weeks apart
  • Oxford/AstraZeneca and Pfizer/BioNTech - 28 days apart
  • Oxford/AstraZeneca and Pfizer/BioNTech - 12 weeks apart
  • Pfizer/BioNTech and Oxford/AstraZeneca - 28 days apart
  • Pfizer/BioNTech and Oxford/AstraZeneca - 12 weeks apart

Patients are to be recruited over the course of February 2021 via the NHS COVID-19 Vaccine Research Registry, with vaccinations expected to start towards the middle of the month and initial results to be made available over the summer period.

The study will last for 13 months, and the UK public can volunteer to be contacted about taking part in the study and further COVID-19 vaccine studies by joining the research registry via the Coronavirus vaccine research page on the NHS website, or visiting the Com-Cov vaccine trial website to find out more about the study and see if there is a study site near them. 

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 definitely advantages to having data that could support a more flexible immunisation programme, if ever needed and approved by the medicines regulator.

"This study will be a promising opportunity to gain greater insight into how we can use the vaccines to stay on top of this nasty disease."

Professor Andrew Ustianowski, NIHR Clinical Lead for COVID-19 Vaccination Programme and Joint National Infection Specialty Lead, said:

"This is another exciting step forward in finding a variety of vaccine options for the UK and globally, for which the NIHR is integral to ensuring the participant recruitment for this study and the gaining of robust data on safety and effectiveness. 

"We need people from all backgrounds to take part in this trial, so that we can ensure we have vaccine options suitable for all. Signing up to volunteer for vaccine studies is quick and easy via the NHS Vaccine Research Registry."

The UK public can continue to support the national effort to speed up vaccine research and receive more information about volunteering for future vaccine studies by visiting the Coronavirus vaccine research page on the NHS website.

Image courtesy of John Cairns, University of Oxford.