COV-BOOST Evaluating COVID-19 Vaccine Boosters

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 but which may be approved later in the year. 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”), and BNT1162b2 (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. This study is trying to find out which vaccines against COVID-19 are most effective as a booster vaccination, depending on which vaccine was used to provide the initial prime-boost course. We will be enrolling men and women over the age of 30 who received their initial prime-boost course of vaccination against COVID-19 in December 2020 or January 2021.