A study led by Southampton NHS Foundation Trust will trial the efficacy of seven different Covid-19 vaccines in patients who are given a third dose.

The COV-Boost study will be used to discover whether a third dose of the vaccine could provide added protection against variants of concern, which might make the immune response from vaccination less effective. 

The researchers will also test which vaccine is most effective, in order to establish which jab would be best at protecting the most vulnerable from the virus.

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The trial will be vital for scientists trying to understand how long immune protections lasts, as currently, although we know the Covid-19 vaccines are very effective at preventing severe disease, we do not know how long this protection lasts. 

It is therefore likely that additional, “booster” vaccinations might be needed for high risk groups after a period of time to provide added protection.

The first clinical study in the world to look at the impact of a booster jab

The health secretary, Matt Hancock, said the trial will be the first clinical study in the world to look at the impact of a booster jab. He said: “I’m delighted to be able to announce a new clinical trial, backed by £19 million of taxpayers’ money to look at the use of current Covid vaccines as booster vaccines, and to see...what part they can play in keeping us safe for the long-term.

“I’m very pleased that we’re leading the way with this scientific endeavour, just as we have so many times in this crisis.”

The study will be delivered across a network of trial sites in the UK, beginning in June. Initially, the researchers will be enrolling men and women over the age of 30 who received their first vaccine in December 2020 or January 2021.

However, any adults who are 84 days post second vaccination are able to take part. If you put yourself forward for the trial, you must be willing to tell trial staff your medical history and agree not to donate blood during the trial. Those who are able to become pregnant must also provide a negative pregnancy test on the day of the vaccination.

Which vaccines will be used in the study?

Participants will be allocated at random to receive one dose of the control group vaccine, or one of the seven available vaccines, which are: AstraZeneca, Pfizer, Moderna (which are approved by the MHRA), or Janssen, Novavax, Valneva and CureVac (which are still under review). Novavax, Valneva and CureVac will also be trialled as a half dose to find out whether a smaller dose will still provide the same or similar protection.

Chief Investigator and Director of NIHR Southampton Clinical Research Facility Professor Saul Faust said: "This trial will give the Joint Committee on Vaccination and Immunisation the important data to inform their recommendations of how to protect the population against any future wave.

"It is fantastic that so many people across the country have taken part in vaccine trials up to now so that we can be in a position to study the effects of boosters, and we hope that as many people as possible over the age of 30 who received their first dose early in the NHS programme will be able to take part."

To find out more or to sign up to take part in the trial, please visit the COV-Boost website.