SIX COVID-19 vaccines are safe and boost immunity for people who have had two doses of AstraZeneca or Pfizer-BioNTech, results from a UK-wide COV-BOOST trial reveal.

The study, led by University Hospital Southampton, was key to shaping the UK booster programme and provides evidence for global vaccination efforts.

COV-BOOST looked at the safety, immune responses and side-effects of seven vaccines when used as a third booster jab.

It saw 2,878 people aged 30 or over receive one booster 10 to 12 weeks after their initial two-dose vaccination with either AstraZeneca or Pfizer-BioNTech.

Daily Echo: University Hospital Southampton lead UK-wide Covid booster jab trial University Hospital Southampton lead UK-wide Covid booster jab trial

The results have been described as "really encouraging."

Professor Saul Faust, trial lead and director of the NIHR clinical research facility at University Hospital Southampton NHS Foundation Trust (UHS), said: "It’s really encouraging that a wide range of vaccines, using different technologies, show benefits as a booster dose to either of these vaccines.

"That gives confidence and flexibility in developing booster programmes here and globally, with other factors like supply chain and logistics also in play."

Kate Hedger, 62, a retired radiographer from Fareham, took part in the trial in an effort to continue to support the pandemic response after retiring.

She said: "It’s been a very positive experience. Participating in research comes with a sort of a feel-good factor, it feels like you're doing your bit and I would really encourage other people to do the same.

"I’m so proud to have been a part of the trial and the fact that the results are of such importance internationally is just fantastic."

The seven vaccines trialled were: Oxford-AstraZeneca, Pfizer-BioNTech, Moderna, Novavax, Valneva, Janssen and CureVac.

Half-doses of Pfizer-BioNtech, Novavax and Valneva were also tested.

A control group was given a meningitis vaccine, to account for reactions not specific to the Covid-19 jabs.

Large differences were noted in spike protein antibody levels after 28 days across all of the vaccines.

All seven of the trialled vaccines boosted levels of spike protein antibodies significantly after two doses of AstraZeneca.

However, only six also did so after two doses of Pfizer-BioNTech, with those being AstraZeneca, Pfizer-BioNTech, Moderna, Novavax, Janssen and CureVac.

For those who had received two initial doses of AstraZeneca, the levels ranged from 1.8 times higher to 32.3 times higher with different booster vaccines, while the levels for those who had received Pfizer-BioNTech initially were 1.3 times higher to 11.5 times higher.

Booster results were similar for those aged 30-69 years and those aged 70 years or older.

Professor Faust said: "It’s important to note two things about these results. First, they only relate to these vaccines as boosters to the two primary vaccinations, not how well they work as first and second doses.

"Secondly, the data describe the immune response at 28 days, not vaccine effectiveness. The relationship between that response and long-term protection is still poorly understood.

"We will be looking at the longer-term immune responses in COV-BOOST, conducting further tests at three months and one year after receiving boosters.

"We are also looking at whether a longer period between second and third doses improves response to the two of the booster vaccines. Several studies have shown this effect between first and second doses.

"We’ve done that by giving some of our original control participants the booster at a later point, and we expect those results to be available in the new year."