The UK has been at the forefront of the global efforts to vaccinate against Covid-19 and a new £7m study is set to begin at sites across England to examine the efficacy of using different approved vaccines for the two doses.
The NIHR-supported study, which has received its funding direct from the UK Government, will also investigate different dosing intervals.
Referred to as the Covid-19 Heterologous Prime Boost study - or ‘Com-Cov’ - the clinical study will determine whether it is as effective to use a different approved vaccine for the second dose as was given for the first, which if proven safe and suitable would further bolster UK vaccination capabilities and minimise the potential disruption supply chain difficulties could cause.
Over 800 volunteers are expected to be recruited in the study, aged 50 and over.
The clinical study will operate out of eight sites across England, including Oxford, London, Birmingham, Liverpool, Nottingham, Bristol and Southampton.
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 Covid-19 Vaccine Research Registry."
Deputy Chief Medical Officer and Senior Responsible Officer for the study, Professor Jonathan Van-Tam, added: “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.
“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 be a promising opportunity to gain greater insight into how we can use the vaccines to stay on top of this nasty disease.”
Researchers will 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.
Classified as an Urgent Public Health study by the NIHR, it is being undertaken by the National Immunisation Schedule Evaluation Consortium (NISEC) and the Oxford Vaccine Group.