A new British study will examine whether different vaccines can safely be used for 2-dose regimes in the future.
Patients taking part in a new clinical study launching today will soon receive different COVID-19 vaccines for their first or second dose.
Backed by £7 million of government funding, the study will be the first in the world to determine the effects of using different vaccines for the first and second dose – for example, using Oxford University/AstraZeneca’s vaccine for the first dose, followed by Pfizer/BioNTech’s vaccine for the second.
The study, run by the National Immunisation Schedule Evaluation Consortium (NISEC) across eight National Institute for Health Research (NIHR) supported sites, will also gather immunological evidence on different intervals between the first and second dose for a mixed-vaccine regimen against control groups when the same vaccine is used for both doses.
A same-dose regimen is currently implemented for the national COVID-19 vaccination programme, and there are no current plans for this to change. Anyone who has received either the Pfizer or AstraZeneca vaccination as part of the UK-wide delivery plan will not be affected by this study. They will receive their second dose from the same source and over the same 12-week interval.
The 13-month study will monitor the impact of the different dosing regimens on patients’ immune responses, which have the potential to be higher or lower than from the same dose regimen. Initial findings are expected to be released in the summer. The study has received ethics approval from the Research Ethics Committee, as well as approval from the Medicines and Healthcare products Regulatory Agency (MHRA).
Should the study show promising results, then the government may consider reviewing the vaccine regimen approach if needed, but only if proven to be safe and recommended by the Joint Committee on Vaccination and Immunisation (JCVI).
Minister for COVID-19 Vaccine Deployment, Nadhim Zahawi, said:
Deputy Chief Medical Officer and Senior Responsible Officer for the study, Professor Jonathan Van-Tam, said:
The study will initially have 8 different arms testing 8 different combinations, but more products may be added. The 8 arms include:
- 2 doses of the Oxford/AstraZeneca vaccine at 28 days apart
- 2 doses of the Oxford/AstraZeneca vaccine at 12 weeks apart – as a control group
- 2 doses of the Pfizer/BioNTech vaccine at 28 days apart
- 2 doses of the Pfizer/BioNTech vaccine at 12 weeks apart – as a control group
- the Oxford/AstraZeneca vaccine for the first dose, followed by the Pfizer/BioNTech vaccine for the second, at 28 days apart
- the Oxford/AstraZeneca vaccine for the first dose, followed by the Pfizer/BioNTech vaccine for the second, at 12 weeks apart
- the Pfizer/BioNTech vaccine for the first dose, followed by the Oxford/AstraZeneca vaccine for the second, at 28 days apart
- the Pfizer/BioNTech vaccine for the first dose, followed by the Oxford/AstraZeneca vaccine for the second, at 12 weeks apart
Over 800 patients are expected to take part in the study, referred to as the COVID-19 Heterologous Prime Boost study or ‘Com-Cov’, across 8 different sites across England – including in London, Birmingham and Liverpool.
Patients will be recruited over the course of February 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 UK public can volunteer to be contacted about taking part in the study and further vaccine studies by joining the registry.
The study has been classified as an Urgent Public Health study by the NIHR and is being undertaken by NISEC and the Oxford Vaccine Group, with funding of £7 million from the government through the Vaccines Taskforce.
Chief Investigator Matthew Snape, Associate Professor in Paediatrics and Vaccinology at the University of Oxford, said: