CovBoost: A randomised, phase II UK multi-centre study to determine reactogenicity and immunogenicity of booster vaccination against ancestral and novel variants of SARS-CoV-2
PI: Adrian Palfreeman
The Cov-Boost study, backed by £19.3 million of government funding through the Vaccines Taskforce, is being run in 18 sites across the UK, including the National Institute for Health Research (NIHR) Leicester Clinical Research Facility based at Leicester’s Hospitals. It is the first study in the world to provide vital data on the impact of a third dose on patients’ immune responses.
There are now a number of vaccines that have been approved in the UK to prevent COVID-19 and other vaccines that are still in UK clinical trials. Millions of people have now received their first 2 vaccinations, which we call a “prime-boost” course. There were 2 vaccines used by the NHS to deliver an initial prime-boost during the first part of the NHS immunisation campaign: ChAdOx1-nCov19 (commonly known as the “Oxford vaccine” or ‘AstraZeneca Vaccine’), and BNT162b2 (commonly known as the “Pfizer vaccine”).
Whilst these have been shown to be highly effective at preventing severe disease due to COVID-19, we don’t know how long the immune protection from vaccination will last. In addition, variants of the virus which causes COVID-19 (SARS-CoV-2) have emerged with mutations which might make the immune response from vaccination less effective. It is therefore likely that additional, “booster” vaccinations might be needed for high risk groups after a period of time to provide added protection.
Cov-Boost is trying to find out which vaccines against COVID-19 are effective and safe as a booster vaccination, depending on which vaccine was used to provide the initial prime-boost course. The study will also help to determine whether half doses of some COVID-19 vaccines are sufficient to increase immunity when given as a 3rd dose booster. Being able to give people a half dose means that health services would be able to vaccinate twice as many people with the same amount of vaccine available, so this is another important question. From June 2021 we enrolled 154 men and women 30 years old or over who had received their initial prime-boost course of vaccination against COVID-19. They were then randomised to the Oxford/Astra Zeneca vaccine, Novovax full dose, Novovax half dose or a control vaccine of a Meningitis Booster vaccine.
All participants are being monitored throughout the study for any potential side effects and have bloods taken to measure their immune responses at days 28, 84, 308 and 365, with a small number having additional blood tests at other times. All sites have an electronic diary for all participants that sends alerts to the team in real time if needed and a 24-hour emergency phone to a doctor on the study, who can provide further clinical advice.
The initial findings will help inform decisions by the Joint Committee on Vaccination and Immunisation (JCVI) on any potential booster programme from autumn this year, ensuring the most vulnerable people are given the strongest possible protection over the winter period.
For more information you can visit the study website at www.covboost.org.uk, email firstname.lastname@example.org or call the study team on 0116 2585973.